MODULE 22: MEDICAL ENTOMOLOGY i
1. Module Code: BLS8451 School: Health Sciences
2. Module Title: Medical Entomology I
3. Year: 2 Semester: 2 Credits: 10
4. First year of presentation:
Administering School: Health Sciences
5. a. Core module (Yes or No): Yes
5. b. Elective module (Yes or No): No
5. c. Pre-requisite module(s): NA
5. d. Co-requisite module(s): NA
5. e. Prohibited combinations: NA
1. Team of Instructors: Dr Wossenseged Lemma; Valence; FELIX Tel: 0792626387, Email: wossensegedlemma@yahoo.com
2. NDAHIMANA Felix, Tel: 0782024085, email: ndahifel@gmail.com
3. MUHOZI Valens, Tel: 0788694416, email: muhozival@gmail.com
6. Allocation of study and teaching hours
|
Description |
Student's hours |
Lecturer's hours |
|
Lectures |
30 |
30 |
|
Seminars/workshops |
10 |
10 |
|
Practical classes/laboratory |
15 |
15 |
|
Structured exercises |
5 |
1 |
|
Set reading etc. |
5 |
1 |
|
Self-directed study |
20 |
0 |
|
Assignments – preparation and writing |
10 |
2 |
|
Examination – revision and attendance |
5 |
4 |
|
Total hours |
100 |
63 |
7. Brief description of aims and content
The aim of this module is to help students identify arthropods disease vectors, understand their habitat (ecology), the diseases they transmit and how they should be controlled.
8.Graduate Attributes & Learning Outcomes
A. Knowledge and Understanding
Having successfully completed this module, students should be able to demonstrate knowledge and understanding of:
1. Definition of the concept of medical entomology
2. Identification methods of the major parasite vectors and/or intermediate hosts
3. Classification of the phylum Arthropoda into their various classes
4. Description of ecological niches of arthropods of medical importance
5. Explanation of the relationship between pathogens and arthropods
6. Explanation of the methods used to prevent and control the vectors
B. Cognitive/Intellectual skills/Application of Knowledge
Having successfully completed this module, students should be able to:
1. Articulate methods for controlling arthropod vectors (of pathogens);
2. Appraise present methods of vector control
3. Interpret life histories of selected vectors
A. Communication/ICT/Numeracy/Analytic Techniques/Practical Skills/Information Literacy
Having successfully completed this module, students should be able to:
1. Identify microscopically arthropod vectors of diseases.
2. Determine infectivity of vectors using traditional and molecular methods
3. Describe vector control techniques
4. Communicate the findings in clear and elaborate form
B. General Transferable Skills
Personal, Intellectual, and Professional Autonomy
Having successfully completed this module, students should be able to:
1. Critically read a published paper/book chapter
2. Discuss the different types of vectors and their control methods
Employability and career development
3. Having successfully completed this module, students should be able to:
4. Work in various services and organizations using knowledge learned in this module
Global citizenship
5. Having successfully completed this module, students should be able to:
6. Serve his country/nation with professionalism and patriotism and contribute to solve world
Lifelong learning
7. Having successfully completed this module, students should be able to:
8. Adapt new knowledge to cope with the socioeconomic challenges arising in the changing world
Collaboration, Teamwork and Leadership
9. Having successfully completed this module, students should be able to:
10. Work in a team and independently effectively
Research, Creativity and Innovation, Scholarship and Enquiry
11. Having successfully completed this module, students should be able to:
12. Critically report a situation in entomology setting
13. Design a research question to solve a problem and formulate a clear solution
Ethical, Social and Professional Understanding
14. Having successfully completed this module, students should be able to:
15. Work with ethics and professionalism in vector control activities
Financial Literacy
16. Having successfully completed this module, students should be able to:
17. Determine the cost implications of the vector borne diseases
9.Indicative Content
Unit 1. Introduction to Medical Entomology
1.1. Scope of Medical Entomology
1.2. History of Medical Entomology
1.3. Mechanisms of vector borne disease transmissions
1.4. Medical importance of Arthropods and Mollusks
1.5. Classification of Arthropods and Mollusks
1.6. Insect morphology, Anatomy, Reproduction and Nutrition.
Unit 2. Medical important Arachnids (Acarids)
· External morphology
· Life cycle
· Adult behaviour
· Medical Importance
· Control
Unit 3. Medical important Nematocerans (Mosquitoes, Black flies, Sand flies and Biting midges)
· External morphology
· Life cycle
· Adult behaviour
· Medical Importance
· Control
Unit 4. Medical Important Brachycera(Horse flies) and Cyclorrhapha(tsetse and other flies)
· External morphology
· Life cycle
· Adult behaviour
· Medical Importance
· Control
Unit 5. Medical important Flea, and Lice
· External morphology
· Life cycle
· Adult behaviour
· Medical Importance
· Control
Unit 6. Medical important cockroaches and bugs
· External morphology
· Life cycle
· Adult behaviour
· Medical Importance
· Control
Unit 7. Medical important crustaceans and mollusks
· External morphology
· Life cycle
· Adult behaviour
· Medical Importance
· Control
10. Learning and Teaching Strategy
A variety of teaching and learning strategies will be adopted in this module including lectures, self-directed learning, discussions and student presentations, group work and presentations, discussion of case studies, demonstrations and practical exercise (tutorials). A seminar on entomology research findings will be held
11. Assessment Strategy
- Written examination (test) to assess the student’s knowledge and understanding of Medical Entomology
- Practical examination to assess the student’s practical skills in Medical Entomology
- Oral presentation of case studies, the purpose of which is to help students understand and communicate the knowledge acquired
12. Assessment Pattern
|
Component |
Weighting (%) |
Graduate Attributes & Learning outcomes to be covered |
|
In-course assessment: |
50 |
A1-,A2,C1,C3,D1,B2 D1 |
|
Final assessment: |
50 |
A2,A3,A4.B1,B2,B3,C1,D2 |
13. Strategy for feedback and student support during module
- 10 minutes dedicated to questions, comments and reaction from students at the end of each session
- Office hours’ availability for individual students’ issues
- Class feedback after marking of continuous assessments
14. Teaching/Technical Assistance
The module leader will require a laptop computer, an LCD projector, and a flip chart or black board.
15. Indicative Resources
Core Text Service M.W. 2012. Medical Entomology for Students 5th Edition. CambridgeUniversity Press, New York.b (https://archive.org/details/Medical_Entomology_for_Students_by_Mike_Service)
Background Texts
Rozendaal, J. (1997). Vector Control Methods for use by individuals and communities. Geneva. WHO. (http://www.who.int/whopes/resources/vector_rozendaal/en/)
Gillies M. T. and Coetzee M. (1987)A Supplement to the Anophelinae of Africa South of the Sahara (Afrotropical Region). South African Institute for Medical Research, Johannesburg South Africa (http://mosquito-taxonomic-inventory.info/supplement-anophelinae-africa-south-sahara-afrotropical-region)
Journals
Journal of Medical Entomology
Annual Review of Entomology
Trends in Parasitology (formerly Parasitology today)
American Society of Tropical Medicine and Hygiene
Others: N/A
Please add anything else you think is important: None
16. Module Team
Dr. Emmanuel Hakizimana
17. Unit approval
Deans and Heads of all Departments contributing to the programme to confirm agreement
|
Centres/Schools/Department |
Director/Dean/HOD |
Date |
|
Head of department |
Signature:
|
|
|
|
Print Name: Thaddée NSHIMIYIMANA |
|
|
Dean, School of Health Sciences |
Signature |
|
|
Print Name: Assoc. Prof. Nadine RUJENI |
Seen and agreed
|
Library |
Signature
|
|
|
Print Name: Mr Alphonse NGABONZIZA |
||
|
ICT |
Signature
|
|
|
Print Name: Mrs Sylvie UWAMAHORO |
||
|
Centre for Teaching and Learning Enhancement |
Signature
|
|
|
Print Name: Mr John MUGARURA |
|
MODULE 22: MEDICAL ENTOMOLOGY i
Module Code: BLS8451 School: Health Sciences
Module Title: Medical Entomology I Year: 2 Semester: 2 Credits: 10
First year of presentation:
Administering School: Health Sciences
a. Core module (Yes or No): Yes
b. Elective module (Yes or No): No
c. Pre-requisite module(s): NA
d. Co-requisite module(s): NA
e. Prohibited combinations: NA
Team of Instructors: Dr Wossenseged Lemma; Valence; FELIX Tel: 0792626387, Email: wossensegedlemma@yahoo.com
NDAHIMANA Felix, Tel: 0782024085, email: ndahifel@gmail.com
MUHOZI Valens, Tel: 0788694416, email: muhozival@gmail.com
6. Allocation of study and teaching hours
|
Description |
Student's hours |
Lecturer's hours |
|
Lectures |
30 |
30 |
|
Seminars/workshops |
10 |
10 |
|
Practical classes/laboratory |
15 |
15 |
|
Structured exercises |
5 |
1 |
|
Set reading etc. |
5 |
1 |
|
Self-directed study |
20 |
0 |
|
Assignments – preparation and writing |
10 |
2 |
|
Examination – revision and attendance |
5 |
4 |
|
Total hours |
100 |
63 |
7. Brief description of aims and content
The aim of this module is to help students identify arthropods disease vectors, understand their habitat (ecology), the diseases they transmit and how they should be controlled.
8.Grauate Attributes & Learning Outcomes
A. Knowledge and Understanding
Having successfully completed this module, students should be able to demonstrate knowledge and understanding of:
1. Definition of the concept of medical entomology
2. Identification methods of the major parasite vectors and/or intermediate hosts
3. Classification of the phylum Arthropoda into their various classes
4. Description of ecological niches of arthropods of medical importance
5. Explanation of the relationship between pathogens and arthropods
6. Explanation of the methods used to prevent and control the vectors
B. Cognitive/Intellectual skills/Application of Knowledge
Having successfully completed this module, students should be able to:
1. Articulate methods for controlling arthropod vectors (of pathogens);
2. Appraise present methods of vector control
3. Interpret life histories of selected vectors
A. Communication/ICT/Numeracy/Analytic Techniques/Practical Skills/Information Literacy
Having successfully completed this module, students should be able to:
1. Identify microscopically arthropod vectors of diseases.
2. Determine infectivity of vectors using traditional and molecular methods
3. Describe vector control techniques
4. Communicate the findings in clear and elaborate form
B. General Transferable Skills
Personal, Intellectual, and Professional Autonomy
Having successfully completed this module, students should be able to:
1. Critically read a published paper/book chapter
2. Discuss the different types of vectors and their control methods
Employability and career development
3. Having successfully completed this module, students should be able to:
4. Work in various services and organizations using knowledge learned in this module
Global citizenship
5. Having successfully completed this module, students should be able to:
6. Serve his country/nation with professionalism and patriotism and contribute to solve world
Lifelong learning
7. Having successfully completed this module, students should be able to:
8. Adapt new knowledge to cope with the socioeconomic challenges arising in the changing world
Collaboration, Teamwork and Leadership
9. Having successfully completed this module, students should be able to:
10. Work in a team and independently effectively
Research, Creativity and Innovation, Scholarship and Enquiry
11. Having successfully completed this module, students should be able to:
12. Critically report a situation in entomology setting
13. Design a research question to solve a problem and formulate a clear solution
Ethical, Social and Professional Understanding
14. Having successfully completed this module, students should be able to:
15. Work with ethics and professionalism in vector control activities
Financial Literacy
16. Having successfully completed this module, students should be able to:
17. Determine the cost implications of the vector borne diseases
9.Indicative Content
Unit 1. Introduction to Medical Entomology
1.1. Scope of Medical Entomology
1.2. History of Medical Entomology
1.3. Mechanisms of vector borne disease transmissions
1.4. Medical importance of Arthropods and Mollusks
1.5. Classification of Arthropods and Mollusks
1.6. Insect morphology, Anatomy, Reproduction and Nutrition.
Unit 2. Medical important Arachnids (Acarids)
· External morphology
· Life cycle
· Adult behaviour
· Medical Importance
· Control
Unit 3. Medical important Nematocerans (Mosquitoes, Black flies, Sand flies and Biting midges)
· External morphology
· Life cycle
· Adult behaviour
· Medical Importance
· Control
Unit 4. Medical Important Brachycera(Horse flies) and Cyclorrhapha(tsetse and other flies)
· External morphology
· Life cycle
· Adult behaviour
· Medical Importance
· Control
Unit 5. Medical important Flea, and Lice
· External morphology
· Life cycle
· Adult behaviour
· Medical Importance
· Control
Unit 6. Medical important cockroaches and bugs
· External morphology
· Life cycle
· Adult behaviour
· Medical Importance
· Control
Unit 7. Medical important crustaceans and mollusks
· External morphology
· Life cycle
· Adult behaviour
· Medical Importance
· Control
10. Learning and Teaching Strategy
A variety of teaching and learning strategies will be adopted in this module including lectures, self-directed learning, discussions and student presentations, group work and presentations, discussion of case studies, demonstrations and practical exercise (tutorials). A seminar on entomology research findings will be held
11. Assessment Strategy
- Written examination (test) to assess the student’s knowledge and understanding of Medical Entomology
- Practical examination to assess the student’s practical skills in Medical Entomology
- Oral presentation of case studies, the purpose of which is to help students understand and communicate the knowledge acquired
12. Assessment Pattern
|
Component |
Weighting (%) |
Graduate Attributes & Learning outcomes to be covered |
|
In-course assessment: |
50 |
A1-,A2,C1,C3,D1,B2 D1 |
|
Final assessment: |
50 |
A2,A3,A4.B1,B2,B3,C1,D2 |
13. Strategy for feedback and student support during module
- 10 minutes dedicated to questions, comments and reaction from students at the end of each session
- Office hours’ availability for individual students’ issues
- Class feedback after marking of continuous assessments
14. Teaching/Technical Assistance
The module leader will require a laptop computer, an LCD projector, and a flip chart or black board.
15. Indicative Resources
Core Text Service M.W. 2012. Medical Entomology for Students 5th Edition. CambridgeUniversity Press, New York.b (https://archive.org/details/Medical_Entomology_for_Students_by_Mike_Service)
Background Texts
Rozendaal, J. (1997). Vector Control Methods for use by individuals and communities. Geneva. WHO. (http://www.who.int/whopes/resources/vector_rozendaal/en/)
Gillies M. T. and Coetzee M. (1987)A Supplement to the Anophelinae of Africa South of the Sahara (Afrotropical Region). South African Institute for Medical Research, Johannesburg South Africa (http://mosquito-taxonomic-inventory.info/supplement-anophelinae-africa-south-sahara-afrotropical-region)
Journals
Journal of Medical Entomology
Annual Review of Entomology
Trends in Parasitology (formerly Parasitology today)
American Society of Tropical Medicine and Hygiene
Others: N/A
Please add anything else you think is important: None
16. Module Team
Dr. Emmanuel Hakizimana
17. Unit approval
Deans and Heads of all Departments contributing to the programme to confirm agreement
|
Centres/Schools/Department |
Director/Dean/HOD |
Date |
|
Head of department |
Signature:
|
|
|
|
Print Name: Thaddée NSHIMIYIMANA |
|
|
Dean, School of Health Sciences |
Signature |
|
|
Print Name: Assoc. Prof. Nadine RUJENI |
Seen and agreed
|
Library |
Signature
|
|
|
Print Name: Mr Alphonse NGABONZIZA |
||
|
ICT |
Signature
|
|
|
Print Name: Mrs Sylvie UWAMAHORO |
||
|
Centre for Teaching and Learning Enhancement |
Signature
|
|
|
Print Name: Mr John MUGARURA |
|
Unit 1. Introduction to Medical Entomology I (BLS 8451)
Welcome to Medical Entomology I.
Over this semester, you will go into the world of arthropods and Molluscs with their profound impact on human health in the course of Medical Entomology I which prepares the students for Medical Entomology II.
Course Description
In this first part of Medical Entomology I (Unit 1), We will overview its scope, the reason why we study this course, the mechanisms of vector borne disease transmission and history of medical Entomology. Finally, we will cover some basic aspects of classification, morphology, Physiology, behavior and reproduction of medically important Arthropods and Mollusks. Such brief introduction makes the students easily understand the later units. The other units (Unit 2- 6) deal about medical important Arthropods and mollusks which describe the vector-borne diseases, transmission mechanisms, vector identification, morphology/physiology, life cycles, and public health significance.
Key topics include:
- The study areas in Medical Entomology, significance of Arthropods and Mollusks in human health.
- The historical milestones in medical entomology.
- The fundamental principles of disease transmission, including mechanical, biological, propagative, and transovarian mechanisms.
- The classification of medically important arthropods and mollusks,
- The detailed morphology, anatomy, physiology, and behavior of insects, including the integument, alimentary, circulatory, and reproductive systems in addition to Insect development, metamorphosis (complete and incomplete), and endocrine control of growth.
- The strategies and adaptations for haematophagy (blood-feeding), including host location, mouthpart structure, and the role of salivary components.
Learning Outcomes
Upon successful completion of Unit 1, students will be able to:
- Define the scope of medical entomology and explain the medical, economic, and public health importance of arthropods and mollusks.
- Distinguish between mechanical and biological vectors and describe the different mechanisms of pathogen transmission (e.g., propagative, developmental, transovarian, salivarian, stercorarian).
- Identify the major classes, orders, and families of medically important arthropods (e.g., Diptera, Siphonaptera, Anoplura, Ixodidae) and snails, using basic morphological characteristics and taxonomic keys.
- Describe the fundamental anatomy and physiology of insects, including the integument, alimentary canal, circulatory system (hemolymph), tracheal system, nervous system, and reproductive organs.
- Explain the processes of insect growth, development, and metamorphosis (ametabolous, incomplete/paurometabolous, and complete/holometabolous) and the role of endocrine hormones like ecdysone.
- Analyze the behavioral and physiological adaptations of haematophagous arthropods for locating hosts, feeding (e.g., piercing-sucking mouthparts), and overcoming host defenses (e.g., anticoagulants in saliva).
- Correlate the biology, behavior (e.g., endophagic vs. exophagic, endophilic vs. exophilic), and vector competence of arthropods with the epidemiology and ecology of the diseases they transmit.
- Discuss the historical discoveries and key scientific figures that have shaped the field of medical entomology.
Evaluation
Multiple choice questions.
1. Medical entomology primary focuses on__________ ?
A. the role of insects on the economic loss and environment pollution of a nation
B. the role of arthropods and mollusks in affecting human health directly or indirectly. C. the parasites that are found in the guts of vectors and intermediate hosts D. bacteria and viruses transmitted from one animals to another
2. Which of the following is true about insect vectors and snail intermediate hosts?
A. Sexual reproduction always occurs in both vectors and intermediate hosts
B. Sandflies are examples of vectors while Copepods are examples of intermediate hosts
C. Vectors are always definitive host while intermediate hosts are always not a definitive host
D. Sexual reproduction always takes place in vectors while asexual reproduction always occurs in intermediate host
3. Arthropods are the most successful animals on terrestrial environment due to the evolution of ______. A. modified appendages performing different activities B. blood for circulation of nutrients and gases to and away from the cells C. outer cuticular exo-skeleton resistance to dehydration. D. tracheal system for gas exchange
4. Which of the following disease is not transmitted by Aedes aegypti ?
A. Dengue fever
B. Yellow fever
C. Malaria
D. Chikungunya
5. Why Medical Entomology and Epidemiology of vector borne diseases are said to be “two faces of the same coin”. A. Because Entomology provides all aspects of the vectors that affect disease transmission while epidemiology provides the patterns of the disease transmission dynamics
B. Because Entomology explains outbreak timing, higher risk areas or population while Epidemiology provides evidences about Vector density, infection rate, and biting rate C. Because Entomology provides the specific pathogen that causes the disease while epidemiology provides the method that control the disease D. Because Medical Entomology provides appropriate therapy while epidemiology gives the appropriate vector control program.
6. Which of the following is an example of a disease transmitted by aquatic snails?
A. Onchocerciasis
B. Schistosomiasis (bilharziasis)
C. Lymphatic filariasis
D. Leishmaniasis
7. The condition characterized by an unusually severe psychological fear of arthropods is called:
A. Delusional parasitosis
B. Entomophobia
C. Anaphylaxis
D. Myiasis
8. The medical importance of arthropods is not related to _____? A. Invading human tissues
B. Contaminating food
C. sexual intercourse
D. Envenomation and allergic reactions
9. Mechanical (contaminative) transmission of pathogens by flies is exemplified by:
A. Plasmodium in mosquitoes
B. Cholera and amoeba carried by flies
C. Plague bacilli in fleas
D. Onchocerca in black flies
10. The development of Leishmania parasites in the sand fly is an example of _____? A. Propagative transmission
B. Developmental transmission
C. Cyclopropagative transmission
D. Transovarian transmission
11. Transovarian (hereditary) transmission is particularly common in which arthropod group?
A. Mosquitoes
B. Ticks
C. Sandflies
D. Lice
12. Which type of transmission involves an infected tick passing infection to a non-infected tick feeding nearby on the same host?
A. Venereal transmission
B. Co-feeding
C. Salivarian transmission
D. Regurgitation
13. The complete developmental changes of Plasmodium parasites in Anopheles mosquito was first demonstrated by __________ ?
A. Ronald Ross B. Giovani Grassi C. Patrick Manson D. Watson and Christophers
14. The role of the tsetse fly Glossina palpalis as vector of African trypanosomiasis was discovered by:
A. Patrick Manson
B. David Bruce C. Theobald Smith
D. Carlos Chagas
15. ________is the father of Medical Entomology who discovered the first mosquito vector for filarial worms
A. Ronald Ross
B. Patrick Manson C. Graham
D. Blalock
16. Which class of arthropods is characterized by two body regions (cephalothorax and abdomen), lack of antennae, and four pairs of legs?
A. Insecta
B. Crustacea
C. Arachnida (Chelicerata)
D. Chilopoda
17. Insects that have never had wings during their evolutionary history belong to which subclass?
A. Pterygota
B. Endopterygota
C. Exopterygota
D. Apterygota
18. Complete metamorphosis (holometabolous development) is characteristic of which insect group?
A. Grasshoppers and crickets (Orthoptera)
B. True bugs (Hemiptera)
C. True flies (Diptera) and fleas (Siphonaptera)
D. Lice (Anoplura)
19. The peritrophic membrane (peritrophic matrix) in the insect midgut functions to:
A. Produce digestive enzymes
B. Protect midgut epithelial cells from abrasion and parasitic invasion
C. Store food
D. Excrete nitrogenous waste
20. Which of the following is true about open circulation of Insects?
A. Transport of oxygen to tissues
B. remove co2 from tissues
C. Transport of digested nutrients
D. regulate body temperature
21`. In the female insect, spermatozoa are stored in the:
A. Ovariole
B. Calyx
C. Spermatheca
D. Vagina
22. Insects that undergo simple metamorphosis (egg → nymph → adult) with wings developing externally are called:
A. Endopterygotes
B. Apterygotes
C. Exopterygotes
D. Ametabolous
23. The molting hormone that initiates insect growth and development is:
A. Juvenile hormone
B. Ecdysone (prothoracic gland hormone)
C. Acetylcholine
D. Melatonin
24. Which of the following is a key adaptation of hematophagous (blood-feeding) arthropods?
A. Mandibulate chewing mouthparts
B. Saliva containing anticoagulants and vasodilators
C. Lack of chemoreceptors
D. Incomplete digestive system
25. Host location by tsetse flies and tabanids from long distances is primarily by:
A. Heat change only
B. Odor cues (CO₂, water vapor, lactic acid) and sight
C. Mechanoreceptors only
D. Nest-dwelling adaptation
26. Insects that live near bird or animal nests to have hosts readily available for blood meal are described as:
A. Endophilic
B. Exophagic
C. Nidiculous
D. Zoophilic
27. The excretory organ in insects that opens into the hindgut and removes nitrogenous waste is the:
A. Malpighian tubule
B. Nephridium
C. Proventriculus
D. Crop
28. Which of the following is a correct match between the vector and the disease it transmits?
A. Black flies – Lyme disease
B. Triatomine bugs – Chagas disease
C. Fleas – Onchocerciasis
D. Ticks – Leishmaniasis
29. A major disadvantage of morphological identification keys for insects is:
A. They require expensive technology
B. They cannot identify sibling/cryptic species within a species complex
C. They are not based on any traits
D. They can only identify larvae, not adults
30. Which of the following techniques best identifies members of cryptic species in complexes?
A. PCR (studies of nucleic acids)
B. Electron microscopy only
C. Behavioral observation only
D. Blood meal analysis only
Unit -2. Medical Important Acarids (Mites and Ticks).
Welcome to Unit 2
Welcome to Mites and Ticks. Due to their microscopic size, mites are not familiar like most other arthropods including ticks which we encounter them during our day-to-day activities. But mites are among the most significant arthropods affecting human health—from the relentless itching of scabies affecting over 300 million people annually, to the potentially life-threatening scrub typhus transmitted by chiggers. On the other hand, Ticks are common ecto-parasites of animals and human which transmit different diseases.
Description of the unit 2.
This unit provides a comprehensive overview of medically important acarids (mites and ticks). Students will explore the biology, morphology, life cycles, and clinical significance of key Acarids, including scabies mites (Sarcoptes scabiei), dust mites (Dermatophagoides), follicle mites (Demodex), chigger mites (Trombiculidae), and both hard (Ixodidae) and soft (Argasidae) ticks. The unit emphasizes the direct pathologies caused by these organisms (e.g., scabies, dermatitis, mange) and their role as vectors of serious infectious diseases such as scrub typhus, Lyme disease, tick-borne relapsing fever, Q-fever and so on. Students will also learn evidence-based strategies for diagnosis, personal protection, environmental control, and treatment.
Learning Objectives
Upon successful completion of this course, students will be able to:
- Identify major mite and tick genera of medical importance based on key morphological features (e.g., setal patterns, mouthparts, leg count, body segmentation).
- Differentiate the life cycles and transmission modes of Sarcoptes, Demodex, Trombiculid mites, Ixodid (hard) ticks, and Argasid (soft) ticks.
- Describe the clinical manifestations of acariasis, including scabies (papular, nodular, crusted forms), demodicosis, chigger dermatitis (trombiculiasis), and tick paralysis.
- Explain the vector-pathogen relationship for acarid-borne diseases, specifically scrub typhus (Orientia tsutsugamushi), Lyme disease (Borrelia burgdorferi), and relapsing fever (Borrelia spp.).
- Apply appropriate diagnostic techniques (e.g., mineral oil skin scraping for scabies, microscopic examination of follicular material for Demodex).
- Recommend evidence-based prevention and control measures, including environmental sanitation, personal protective behaviors, and the use of acaricides/repellents (e.g., DEET, permethrin, benzyl benzoate).
Evaluation
Unit 2: Medically Important Acarids — 30 Questions (Correct Answer in Bold)
1. What is the key morphological distinction between adult acarids (mites/ticks) and adult insects?
A. Acarids have antennae; insects do not.
B. Acarids have 6 legs; insects have 8 legs.
C. Acarids have 8 legs; insects have 6 legs.
D. Acarids have wings; insects lack wings.
2. Which morphological feature is used to distinguish ticks from mites?
A. Presence of a scutum (dorsal shield)
B. Presence of a toothed hypostome
C. Presence of setae (bristles) on legs
D. Presence of pedicels (suckers) on legs
3. Which clinical form of scabies is characterized by hyperkeratotic crusts containing millions of mites and minimal itching, typically occurring in immunocompromised patients?
A. Papular scabies
B. Nodular scabies
C. Bullous scabies
D. Crusted (Norwegian) scabies
4. A patient presents with intense pruritus, worse at night, with burrows noted in the interdigital spaces and wrists. What is the most appropriate first-line treatment?
A. Oral ivermectin single dose
B. Permethrin 5% cream (wash off after 8–14 hours)
C. Malathion 0.5% lotion for 24 hours
D. Crotamiton applied once daily
5. House-dust mites (Dermatophagoides spp.) do not bite humans. Their medical importance is primarily due to:
A. Transmitting Rickettsia tsutsugamushi
B. Causing direct skin burrows and mange
C. Inhaled fecal pellets and shed exoskeletons causing allergic disease
D. Injecting a neurotoxin that causes ascending paralysis
6. A 65-year-old patient presents with rosacea and blepharitis. Microscopic examination of epilated eyelashes reveals elongated, worm-like mites with four pairs of stubby legs. What is the most likely genus?
A. Sarcoptes
B. Dermatophagoides
C. Demodex
D. Leptotrombidium
7. Which two Demodex species are commonly found on humans, and what are their primary habitats?
A. D. canis (hair follicles) and D. cati (sebaceous glands)
B. D. folliculorum (hair follicles) and D. brevis (sebaceous glands)
C. D. pteronyssinus (hair follicles) and D. farinae (sebaceous glands)
D. D. hominis (eyelashes) and D. caprae (scalp)
8. Which stage of trombiculid (chigger) mites is parasitic on humans?
A. Egg
B. Larva (first instar)
C. Deutonymph
D. Adult
9. How many pairs of legs does a parasitic chigger larva possess?
A. 2 pairs
B. 3 pairs
C. 4 pairs
D. 5 pairs
10. A soldier returns from Southeast Asia with fever, lymphadenopathy, and an eschar (dark necrotic scab) on his ankle. What is the most likely diagnosis?
A. Lyme disease
B. Scrub typhus (tsutsugamushi disease)
C. Tick-borne relapsing fever
D. Crusted scabies
11. Which of the following correctly describes the feeding duration for soft ticks (Argasidae) compared to hard ticks (Ixodidae)?
A. Soft ticks feed for days to weeks; hard ticks feed for minutes.
B. Soft ticks feed for minutes (20–35 min); hard ticks feed for days to weeks.
C. Both feed for similar durations (24–48 hours).
D. Only adult soft ticks feed; larvae and nymphs do not feed.
12. Soft ticks (Argasidae) are primarily nidicolous, meaning they:
A. Live in open vegetation and quest for hosts.
B. Live in the host's home (burrows, huts, cracks).
C. Feed only on birds and reptiles.
D. Have a single nymphal stage.
13. Which structural feature is present in hard ticks (Ixodidae) but absent in soft ticks (Argasidae)?
A. Coxal organs
B. Ventrally located capitulum (mouthparts)
C. Scutum (dorsal shield)
D. Leg-like palps
14. A child develops ascending flaccid paralysis after a tick is found attached to the scalp. The tick is removed and the child recovers within 48 hours. This condition is most likely:
A. Lyme disease
B. Tick paralysis (neurotoxin from hard tick saliva)
C. Scrub typhus meningitis
D. Relapsing fever neuroborreliosis
15. Which of the following Arthropods are microscopic in size? A. Mites
B. Hard Ticks C. Soft Ticks
D. Mollusks
16. Worldwide distribution and high incidence of scabies is related to _____________ A. its transmission by air
B. contact is the major means of transmission C. its adaptation to the coldest part of the world D. many reservoir animal hosts caring the scabies mites
17. Which of the following is not recommended to treatment scabies?
A. Oral ivermectin for 24 hours
B. Benzyl benzoate (25% emulsion) applied for 24 hours
C. any topical lesion twice daily
D. Oral antihistamines
18. Dust mites are commonly found in all of the following EXCEPT:
A. Beds and mattresses
B. Carpets
C. House dust
D. Human hair follicles
19. What do dust mites feed on?
A. Human blood
B. Skin scales and organic debris
C. Plant pollen
D. Fungal spores
20. Dust mites are associated with all of the following allergic conditions EXCEPT:
A. Asthma
B. Perennial rhinitis
C. Scabies
D. Atopic dermatitis
21. Dust mite allergies can be diagnosed using ____?
A. Microscopic examination of skin scrapings
B. Serological tests of serum
C. searching allergens in the environment D. Burrow ink test
22. Dust mites have mouthparts described as:
A. Piercing‑sucking stylets
B. Pincer chelicerae
C. Chewing mandibles
D. Sponging labellum
23. The body shape of Demodex folliculorum is described as:
A. Round and sack‑like
B. Worm‑like with an annulated abdomen
C. Oval with feather‑like hairs
D. Flattened and leathery
24. Which of the following is a common clinical feature associated with Demodex?
A. Scabies burrows
B. Blackheads (comedowns)
C. Eschar formation
D. Erythema migrans rash
25. Which of the following are the two main groups of ticks?
A. Ixodidae and Argasidae
B. Sarcoptidae and Trombiculidae
C. Demodicidae and Dermanyssidae
D. Metastigmata and Mesostigmata
26. Soft ticks (Argasidae) primarily locate hosts by using which stimuli?
A. Only visual cues
B. CO₂, heat, and movements
C. Only humidity gradients
D. Auditory signals
27. Which bacterium causes Lyme disease?
A. Borrelia duttoni
B. Borrelia burgdorferi
C. Rickettsia tsutsugamushi
D. Francisella tularensis
28. Which protozoan disease transmitted by hard ticks is mentioned?
A. Leishmaniasis
B. Babesiosis (Babesia microti)
C. Malaria
D. Toxoplasmosis
29. Tularemia (rabbit fever) is caused by:
A. Coxiella burnetii
B. Francisella tularensis
C. Borrelia recurrentis
D. Orientia tsutsugamushi
30. Early removal of hard ticks and wearing protective clothing are recommended for control of:
A. Scabies
B. Hard tick‑borne diseases
C. Dust mite allergies
D. Demodicosis
Unit 3. Medically Important Nematocerans
Welcome
Welcome to Unit 3! In this unit, you will explore the fascinating and medically critical group of flies known as Nematocerans – the "thread-horned" flies. While many insects are a nuisance, certain members of this suborder are responsible for transmitting some of the world's most devastating diseases. From malaria and dengue to river blindness and leishmaniasis, these tiny insects have shaped human history and continue to pose major public health challenges globally. This unit will equip you with the essential knowledge to identify, understand, and combat these important disease vectors.
Unit Description
Unit 3 provides a comprehensive overview of the four main families of Nematoceran flies of medical and veterinary importance: Culicidae (mosquitoes) , Simuliidae (black flies) , Psychodidae (sand flies) , and Ceratopogonidae (biting midges). For each family, we will examine their external morphology, life cycles, blood-feeding behaviors, and their specific roles as vectors of pathogens. Special emphasis is placed on the major diseases they transmit, including malaria, filariasis, dengue, onchocerciasis (river blindness), leishmaniasis, sandfly fever, and bartonellosis. The unit concludes with an overview of integrated vector control strategies.
Unit Goals & Learning Objectives
By the end of this unit, you will be able to:
- Distinguish the key morphological features of Nematocerans from other fly suborders (Brachycera).
- Identify the four families of Nematocerans of medical importance and their distinguishing characteristics.
- Describe the complete life cycles of mosquitoes, black flies, sand flies, and biting midges.
- Explain the mechanisms by which each vector transmits pathogens to humans.
- Compare and contrast the major diseases caused by these vectors, including their etiological agents, clinical features, and epidemiology.
- Differentiate between anopheline and culicine mosquitoes at egg, larval, pupal, and adult stages.
- List and describe the main control methods (physical, chemical, biological, genetic, and environmental) used against Nematoceran vectors.
Unit 3 Contents
3.1 Introduction to Nematocera
3.2 Mosquitoes (Family Culicidae)
3.3 Black Flies (Family Simuliidae)
3.4 Sand Flies (Family Psychodidae, Subfamily Phlebotominae)
3.5 Biting Midges (Family Ceratopogonidae)
Evaluation
Multiple choice Questions.
1. Which of the following is a characteristic feature of the suborder Nematocera?
A. Short, 3‑segment antennae with arista
B. Larval head reduced and often retracted
C. Long antennae with 6 or more segments
D. Pupation inside a puparium (Cyclorrhapha)
2. Which family of Nematocerans does NOT suck blood?
A. Culicidae
B. Simuliidae
C. Toxorhynchitinae
D. Ceratopogonidae
3. The slender body of a mosquito is covered with:
A. Scales and hairs
B. Only hairs
C. A hard exoskeleton without scales
D. Mucous glands
4. In mosquitoes, the two hind wings are modified into:
A. Halteres
B. Claspers
C. Spiracles
D. Palps
5. Which subfamily of Culicidae has a smoothly rounded scutellum and palps as long as the proboscis in females?
A. Culicinae
B. Anophelinae
C. Toxorhynchitinae
D. Simuliinae
6. During a mosquito bite, which mouthpart curves backward while the rest penetrate the skin?
A. Labrum
B. Hypopharynx
C. Mandible
D. Labella of the labium
7. A mosquito that requires a blood meal to develop eggs is called:
A. Autogenous
B. Anautogenous
C. Parous
D. Nulliparous
8. Which term describes a mosquito that has laid eggs at least once?
A. Nulliparous
B. Parous
C. Gravid
D. Anautogenous
9. Which of the following is NOT one of the four main families of blood‑feeding Nematocerans?
A. Culicidae
B. Tabanidae
C. Simuliidae
D. Psychodidae
10. Toxorhynchites mosquitoes are unusual because:
A. Only females suck blood
B. They transmit dengue
C. Neither sex sucks blood
D. They have a short proboscis
11. A floating “egg raft” is characteristic of which genus?
A. Anopheles
B. Aedes
C. Culex
D. Toxorhynchites
12. Mansonia species attach their eggs to:
A. The water surface singly
B. Submerged clusters
C. The undersides of floating plants
D. Dry soil above water
13. Anopheline larvae can be distinguished from culicine larvae by:
A. Presence of a long siphon
B. Absence of a siphon and presence of palmate hairs
C. Bottom‑feeding behavior
D. Having spiracles on segment 8
14. Culicine larvae typically:
A. Hang upside down from the water surface using a siphon
B. Lie parallel to the water surface without a siphon
C. Bury themselves in mud
D. Swim actively with their prolegs
15. Turgal plates are found on the larvae of:
A. Culex
B. Aedes
C. Anopheles
D. Culiseta
16. The siphon of Culex larvae is described as:
A. Short and barrel‑shaped with one pair of tufts
B. Long and narrow with more than one pair of subventral tufts
C. comma shaped barrel
D. Curved like a hook
17. Mosquito pupae are of which type?
A. Coarctate
B. Obtect (appendages visible, not fused in a puparium)
C. Puparium (Cyclorrhapha)
D. Exarate without movement
18. In malaria transmission, the definitive host is:
A. Human
B. Anopheles C. Culex D. Bird
19. Approximately how many sporozoites can accumulate in the salivary glands of an infected Anopheles mosquito?
A. 1,000 – 2,000
B. 10,000 – 15,000
C. 60,000 – 70,000
D. 500,000 – 1 million
20. Bancroftian filariasis is caused by:
A. Brugia malayi
B. Onchocerca volvulus
C. Wuchereria bancrofti
D. Mansonella perstans
21. After a mosquito ingests microfilariae, where do they develop into third‑stage infective larvae?
A. Midgut epithelium
B. Malpighian tubules
C. Thoracic muscles
D. Salivary glands
22. Dengue virus is primarily transmitted by:
A. Anopheles gambiae
B. Culex pipiens
C. Aedes aegypti
D. Mansonia uniformis
23. In the malaria life cycle, the sporozoites are found in the mosquito’s:
A. Hemocoel and salivary glands
B. Midgut epithelium
C. Fat body
D. Ovarioles
24. Once an Anopheles mosquito becomes infective with malaria:
A. It remains infective for only one week
B. It remains infective throughout its life
C. It loses infectivity after laying eggs
D. It needs another blood meal to activate sporozoites
25. Black flies (Simuliidae) are vectors of:
A. Leishmaniasis
B. Onchocerciasis (river blindness)
C. Dengue
D. Bartonellosis
26. The rasp‑like mouthparts of black flies are adapted for:
A. Piercing deep blood vessels
B. Rupturing fine blood capillaries
C. Lapping surface fluids
D. Scraping skin scales
27. Black fly eggs are typically laid:
A. Singly on dry soil
B. In floating rafts
C. On partially submerged objects in flowing water
D. Inside the human skin
28. In the life cycle of Onchocerca volvulus, the infective third‑stage larvae are found in which part of the black fly?
A. Midgut
B. Hemocoel
C. Head and mouthparts
D. Anal papillae
29. Which genus of sand fly is known to transmit Leishmania in the Old World?
A. Lutzomyia
B. Sergentomyia
C. Phlebotomus
D. Culicoides
30. Sand flies belong to the family:
A. Simuliidae
B. Psychodidae
C. Ceratopogonidae
D. Culicidae
31. A key identifying feature of phlebotomine sand flies is:
A. Wings folded like scissors at rest
B. Second wing vein branched twice
C. Long siphon on larvae
D. Humeral pits on thorax
32. Sandfly fever (Papatasi fever) is caused by a:
A. Bacterium
B. Protozoan
C. Virus
D. Filarial worm
33. Carrion’s disease (bartonellosis) is transmitted by sand flies of the genus:
A. Phlebotomus
B. Sergentomyia
C. Lutzomyia
D. Leptoconops
34. Biting midges of medical importance belong mainly to the genus:
A. Forcipomyia
B. Culicoides
C. Austroconops
D. Leptoconops
35. The sterile male technique is an example of:
A. Chemical control
B. Genetic control
C. Mechanical control
D. Biological control using Bti
36. Long‑lasting insecticide‑treated bed nets (LLINs) are a form of control against:
A. Larvae
B. Adult mosquitoes
C. Black fly eggs
D. Sand fly pupae
37. The most commonly used synthetic repellent in the world is:
A. Permethrin
B. Bti
C. DEET (N,N‑Diethyl‑m‑toluamide)
D. Temephos
38. The WHO Onchocerciasis Control Programme (OCP) in West Africa used massive aerial larviciding with:
A. DDT
B. Bti only
C. Temephos
D. Ivermectin alone
40. Which chemical is used in mass drug administration to kill microfilariae in onchocerciasis?
A. DEET
B. Permethrin
C. Ivermectin
D. Temephos
Unit 4. Medical Important Brachycera and Cyclorrhapha
Welcome to Unit 4
Welcome, students! In this unit, we explore the fascinating and medically important world of Brachycera and Cyclorrhapha—the short-horned flies and their most advanced relatives. From the painful bites of horse flies and stable flies to the transmission of deadly diseases like sleeping sickness by tsetse flies, and from myiasis-causing bot flies to the ubiquitous house fly that contaminates our food, this unit covers the flies that directly impact human and animal health. Understanding their morphology, life cycles, behavior, and medical significance is essential for anyone pursuing careers in public health, parasitology, entomology, or clinical medicine.
Unit 4 Description
This unit provides a comprehensive overview of medically important flies within the suborders Brachycera and Cyclorrhapha. Key topics include:
- General characteristics of Brachycera and Cyclorrhapha, including larval morphology
- Tabanidae (horse flies and deer flies) – morphology, life cycle, behavior, and their role as mechanical vectors of anthrax, Lyme disease, trypanosomes, and biological vectors of Loa loa
- Glossinidae (tsetse flies) – classification into three groups (fusca, palpalis, morsitans), morphology, life cycle, behavior, and their role in transmitting African trypanosomiasis (Gambian and Rhodesian sleeping sickness)
- Muscidae – house flies (Musca domestica), stable flies (Stomoxys calcitrans), and lesser house flies (Fannia spp.) – morphology, life cycles, medical importance as mechanical vectors of numerous pathogens, and control strategies
- Myiasis – definitions (accidental, facultative, obligatory), clinical presentations (cutaneous, wound, intestinal), and the fly families involved (Calliphoridae, Sarcophagidae, Oestridae, Cuterebridae, Gasterophilidae)
- Prevention and control – environmental sanitation, insecticides, sterile male technique, traps, and personal protective measures
Unit 4 Learning Objectives (Goals/Outcomes)
By the end of this unit, you should be able to:
- Differentiate between Brachycera and Cyclorrhapha based on adult and larval characteristics.
- Identify the major families of medically important Brachycera and Cyclorrhapha and their common names.
- Describe the external morphology of Tabanidae, Glossinidae, and Muscidae, including key identifying features (antennae, wing venation, mouthparts).
- Explain the life cycles of horse flies, tsetse flies, house flies, and stable flies, including larval habitats and developmental stages.
- Discuss the medical importance of each group, including diseases transmitted (e.g., loiasis, trypanosomiasis, anthrax, Lyme disease) and mechanisms (mechanical vs. biological vectors).
- Define myiasis and distinguish between accidental, facultative, and obligatory myiasis with examples.
- Identify the fly families and species responsible for myiasis in humans and animals (e.g., screwworm, bot fly, tumbu fly).
- Compare control strategies for different fly groups, including environmental management, traps, insecticides, and the sterile insect technique.
- Apply knowledge of fly behavior (feeding preferences, resting sites, breeding habitats) to design effective prevention measures.
Unit 4 Evaluation: 50 Multiple Choice Questions
1. Which of the following is a characteristic of adult Brachycera?
A) Long, multi-segmented antennae
B) Stout bodies with short antennae
C) Larvae with a well-developed head capsule
D) Wings held horizontally at rest
2. Which family includes the horse flies and deer flies?
A) Glossinidae
B) Muscidae
C) Tabanidae
D) Calliphoridae
3. The tsetse fly belongs to which genus?
A) Tabanus
B) Musca
C) Glossina
D) Chrysops
4. Which of the following is a medically important parasite transmitted by Chrysops (deer flies)?
A) Trypanosoma brucei gambiense
B) Loa loa
C) Bacillus anthracis
D) Borrelia burgdorferi
5. The wing venation feature used to identify tsetse flies is a:
A) Closed discal cell in the center of the wing
B) Hatchet cell (chopper) between veins 4 and 5
C) Two submarginal cells and five posterior cells
D) Banded or mottled wing pattern
6. At rest, tsetse flies hold their wings:
A) Spread flat horizontally
B) Over the abdomen like closed scissors
C) Vertically above the body
D) Folded in a Z-shape
7. Which tsetse fly group is primarily associated with riverine vegetation and is a vector of Gambian sleeping sickness?
A) fusca group
B) morsitans group
C) palpalis group
D) haemorrhoidalis group
8. All of the following are medically important Tabanidae genera EXCEPT:
A) Tabanus
B) Haematopota
C) Glossina
D) Chrysops
9. The interrupted feeding behavior of tabanids (stopping and restarting feeding on the same or different hosts) increases their role as:
A) Biological vectors
B) Mechanical vectors
C) Obligatory parasites
D) Predators
10. Which disease is caused by Trypanosoma brucei rhodesiense and transmitted by the morsitans group of tsetse flies?
A) Chagas disease
B) Gambian sleeping sickness
C) Rhodesian sleeping sickness
D) Loiasis
11. The antennae of tabanids lack which structure that is present in Muscidae, Glossinidae, and Calliphoridae?
A) Scape
B) Pedicel
C) Arista
D) Flagellum
12. Larvae of Tabanidae are characterized by:
A) A well-developed head capsule with chewing mouthparts
B) Pseudopods on segments 4–10 and a Graber's organ
C) Three pairs of true legs on the thorax
D) A long breathing tube (siphon) for atmospheric oxygen
13. Which tsetse fly group is NOT a vector of sleeping sickness?
A) palpalis group
B) morsitans group
C) fusca group
D) All groups are vectors
14. The stable fly (Stomoxys calcitrans) differs from the house fly in that it has:
A) A non-biting proboscis
B) A rigid, forward-projecting proboscis for biting
C) Hairy arista on the third antennal segment
D) Four dorsal thoracic stripes
15. Which of the following Muscidae is known for transmitting polio, cholera, typhoid, and shigellosis?
A) Stomoxys calcitrans
B) Musca domestica
C) Fannia canicularis
D) Glossina palpalis
16. The sterile insect technique (SIT) has been successfully used to eradicate:
A) Glossina morsitans from East Africa
B) Cochliomyia hominivorax from the southern USA and Mexico
C) Musca domestica from urban areas
D) Chrysops from West Africa
17. Myiasis caused by larvae that normally are free-living but occasionally infest living tissue is called:
A) Accidental myiasis
B) Facultative myiasis
C) Obligatory myiasis
D) Primary myiasis
18. The human bot fly (Dermatobia hominis) belongs to which family?
A) Calliphoridae
B) Sarcophagidae
C) Oestridae (Cuterebridae)
D) Gasterophilidae
19. Larviparous flies (e.g., some flesh flies) deposit:
A) Eggs on fresh wounds
B) Larvae directly onto the host
C) Pupae in soil
D) Eggs on aquatic plants
20. The "Discal cell" in the wing is a diagnostic feature for:
A) Tabanidae
B) Glossinidae
C) Muscidae
D) Calliphoridae
21. Which of the following is an example of obligatory myiasis?
A) House fly larvae ingested in contaminated food
B) Screwworm larvae developing in an open wound
C) Bot fly larvae always requiring a living host
D) Flesh fly larvae found in carrion
22. Female tabanids locate hosts primarily by:
A) Smell and heat
B) Sight (attracted to dark or colored objects)
C) Sound
D) Chemical pheromones
23. The tsetse fly is unique among the flies discussed because:
A) Only females take blood meals
B) Both sexes take blood meals
C) Neither sex takes blood meals
D) Only males take blood meals
24. Which of the following pathogens is biologically transmitted by Tabanidae?
A) Trypanosoma brucei
B) Loa loa
C) Bacillus anthracis (anthrax)
D) Wuchereria bancrofti
25. The pupal stage of tsetse flies occurs:
A) In water
B) Inside a barrel-shaped puparium in the soil
C) Within the female's uterus
D) On the host's skin
26. Which of the following statements about house flies (Musca domestica) is TRUE?
A) They have biting mouthparts
B) They frequently regurgitate and defecate on food
C) They cannot fly more than 100 meters from breeding sites
D) They are active only at night
27. Intestinal myiasis is typically classified as:
A) Obligatory myiasis
B) Facultative myiasis
C) Accidental myiasis
D) Cutaneous myiasis
28. The lesser house fly (Fannia canicularis) can be distinguished from the house fly by:
A) Four dark thoracic stripes
B) no hairy arista
C) Forward-projecting proboscis
D) Hatchet cell in the wing
29. The morsitans group of tsetse flies inhabits:
A) Equatorial forests
B) Riverine vegetation
C) Savannah regions
D) High-altitude grasslands
30. Which of the following is a control method specifically targeting tsetse flies?
A) Draining marshes and swamps
B) Blue cloth screens/traps impregnated with insecticides
C) Removing decaying organic matter
D) Using mosquito nets
31. Larvae of Tabanidae that are predacious or cannibalistic belong to which genera?
A) Chrysops
B) Tabanus and Haematopota
C) Glossina
D) Musca
32. Which myiasis-causing fly deposits eggs on sand, soil, or clothing, and larvae infect unbroken skin?
A) Cochliomyia hominivorax
B) Cordylobia anthropophaga (tumbu fly)
C) Dermatobia hominis
D) Gasterophilus intestinalis
33. The family Sarcophagidae (flesh flies) is medically important because they cause:
A) Loiasis
B) Wound myiasis
C) African trypanosomiasis
D) Anthrax
34. The preferred resting sites for tsetse flies are:
A) On animal fur
B) On vegetation (<4 meters high)
C) Inside human dwellings
D) In water
35. The anterior spiracles of house fly larvae are described as:
A) D-shaped
B) Pyriform
C) Button-shaped
D) Tubular
36. The condition where fly larvae infest living human or animal tissue is called:
A) Helminthiasis
B) Myiasis
C) Trypanosomiasis
D) Loiasis
37. Which of the following is a key morphological difference between stable flies (Stomoxys calcitrans) and tsetse flies?
A) Stable flies lack a hatchet cell in the wing
B) Stable flies have feathery arista
C) Tsetse flies have four thoracic stripes
D) Stable flies fold wings like scissors at rest
38. To extract a bot fly larva from the skin, one can cover the swelling with liquid paraffin. This works because:
A) It kills the larva instantly
B) It prevents the larva from breathing through its posterior spiracles, forcing it to emerge
C) It dissolves the larval cuticle
D) It numbs the host's skin
39. The fusca group of tsetse flies is primarily found in:
A) Savannah regions
B) Equatorial forests
C) Riverine vegetation
D) Desert margins
40. Which of the following families is known for causing obligatory myiasis in the form of bot flies, warble flies, and horse bot flies?
A) Calliphoridae
B) Sarcophagidae
C) Oestridae (including Cuterebridae and Gasterophilidae)
D) Muscidae
Unit 5: Medically Important Fleas and Lice.
Welcome Message
Welcome to Unit 5: Medically Important Fleas and Lice. In this unit, we will explore two orders of obligate ectoparasites: Siphonaptera (fleas) and Phthiraptera (lice). Despite their small size, these arthropods are of immense public health importance due to their blood-feeding habits and their ability to transmit bacterial, viral, and protozoal diseases. From the bubonic plague to epidemic typhus, these tiny creatures have shaped human history. Let's begin this fascinating journey into the world of fleas and lice.
Course Description
This unit provides a comprehensive overview of fleas and lice as medically significant ectoparasites. Students will learn to classify major species, describe their external morphology and life cycles, and identify the specific diseases they transmit, including plague, endemic typhus, epidemic typhus, and relapsing fever. The unit also covers the clinical presentations of these diseases and emphasizes evidence-based public health measures for their control and prevention.
Learning Objectives (Goals)
By the end of this unit, students will be able to:
- Classify medically important fleas and lice into their respective orders and genera.
- Describe the key morphological features and complete life cycles of fleas and lice.
- Identify the major diseases transmitted by each group and their respective pathogens.
- Differentiate the clinical presentations of flea-borne diseases (e.g., bubonic plague) from louse-borne diseases (e.g., epidemic typhus).
- Apply appropriate public health control measures to manage and prevent flea and louse infestations and their associated diseases.
Contents
5.1. Medically Important Fleas
5.2. Medically Important Lice
1. Fleas belong to which order?
A. Phthiraptera
B. Anoplura
C. Siphonaptera
D. Diptera
2. Which of the following is the primary vector of Yersinia pestis, the bacterium that causes plague?
A. Ctenocephalides felis
B. Pulex irritans
C. Xenopsylla cheopis
D. Tunga penetrans
3. The chigoe or jigger flea, which burrows into the skin of humans, is scientifically known as:
A. Xenopsylla cheopis
B. Ctenocephalides canis
C. Pulex irritans
D. Tunga penetrans
4. The most common clinical form of plague, characterized by swollen, inflamed lymph nodes called buboes, is:
A. Septicemic plague
B. Pneumonic plague
C. Bubonic plague
D. Enteric plague
5. Which form of plague is transmissible via airborne droplets from person to person?
A. Bubonic plague
B. Septicemic plague
C. Pneumonic plague
D. Sylvatic plague
6. The presence of a meral rod and the absence of both genal and pronotal combs are diagnostic morphological features of which flea genus?
A. Ctenocephalides
B. Xenopsylla
C. Tunga
D. Pulex
7. Which flea genus possesses both genal and pronotal combs (ctenidia) as well as a meral rod?
A. Xenopsylla
B. Tunga
C. Ctenocephalides
D. Pulex
8. The sensilium or pygidium, found on a flea's 8th abdominal segment, is primarily a__________.
A. Reproductive organ
B. Jumping apparatus
C. Sensory structure
D. Blood-sucking mouthpart
9. Flea larvae primarily feed on:
A. Host blood directly
B. Only plant matter
C. Organic debris, including dried blood and feces
D. Other insect larvae
10. Rickettsia typhi, the agent of flea-borne endemic typhus, is transmitted to humans via:
A. The flea's bite saliva
B. Infective flea eggs
C. Infected flea feces rubbed into abrasions
D. Inhalation of flea pupae
11. For effective flea control, insecticidal treatments should be repeated every 2 weeks for about 6 months primarily because:
A. Adult fleas live for 2 years
B. Flea eggs are laid every day
C. Flea cocoons are resistant to insecticides and larvae/pupae continue to emerge
D. Fleas become resistant to insecticides in 2 weeks
12. Lice of medical importance belong to which order?
A. Siphonaptera
B. Phthiraptera (formerly Anoplura)
C. Diptera
D. Hemiptera
13. Which of the following is NOT a louse species that parasitizes humans?
A. Pediculus humanus (body louse)
B. Pediculus capitis (head louse)
C. Pthirus pubis (pubic or crab louse)
D. Pulex irritans (human flea)
14. The body louse and head louse are now considered:
A. Two distinct genera
B. Two species of the same genus Pediculus
C. The same species with different ecological niches
D. Two different orders
15. The tough, pigmented skin condition associated with chronic body louse infestation is known as:
A. Pediculosis
B. Vagabond's disease (morbus errorum)
C. Scabies
D. Dermatitis herpetiformis
16. Rickettsia prowazekii, the agent of louse-borne epidemic typhus, multiplies in the louse's stomach and is transmitted to humans via:
A. The louse's bite
B. Infected louse feces rubbed into scratches or mucous membranes
C. Inhaling the louse's saliva
D. The louse's eggs
17. The spirochete Borrelia recurrentis, which causes louse-borne epidemic relapsing fever, is transmitted when:
A. The louse defecates near a wound
B. An infected louse is crushed and its hemolymph enters broken skin or mucous membranes
C. The louse bites and salivates
D. A person ingests contaminated food
18. The pubic or crab louse, Pthirus pubis, is mologically distinguished from Pediculus by its:
A. Long, narrow body
B. Almost round body with massive morphclaws on middle and hind legs
C. Presence of compound eyes
D. Two prominent cerci
19. Which louse species has been proven to be a vector of rickettsiae or spirochetes?
A. Pediculus humanus
B. Pediculus capitis
C. Pthirus pubis
D. Tunga penetrans
20. The life cycle of a louse includes all of the following stages EXCEPT:
A. Egg (nit)
B. Nymph (three instars)
C. Pupa
D. Adult
21. Louse eggs (nits) are firmly cemented to:
A. The host's skin
B. The host's hair or clothing fibers (depending on louse species)
C. The walls of the nest/burrow
D. The floor
22. In the classic plague transmission experiment by Simond and Verjbitskj, the pathogen moved from:
A. Sick rat → flea → healthy rat
B. Sick human → louse → healthy human
C. Sick rat → louse → healthy rat
D. Sick human → flea → healthy human
23. Which of the following statements is TRUE regarding Tunga penetrans?
A. The male burrows into human skin permanently
B. The female burrows into human skin C. It is the primary vector of plague
D. It transmits Rickettsia typhi
24. All of the following are key pathogens transmitted by fleas EXCEPT:
A. Yersinia pestis
B. Rickettsia typhi
C. Borrelia recurrentis
D. Dipylidium caninum (as an intermediate host)
25. The proventriculus is the site of blockage in the flea's gut that leads to regurgitation of Yersinia pestis during feeding. This occurs because the bacteria:
A. Kill the flea's stomach cells
B. Multiply and form a biofilm that blocks the proventriculus
C. Produce a toxin that causes muscle spasms
D. Destroy the flea's immune system
26. A patient presents with fever, severe headache, and dark red spots on their trunk. They are homeless and have body lice. The most likely diagnosis is:
A. Bubonic plague
B. Endemic typhus
C. Epidemic typhus
D. Relapsing fever
27. A wildlife biologist in Arizona dies after performing a necropsy on a mountain lion without proper protection. The cause was confirmed to be Yersinia pestis. This indicates the biologist likely had which form of plague?
A. Bubonic from a flea bite
B. Septicemic from a cut
C. Pneumonic from inhaling infectious droplets/aerosols during necropsy
D. Enteric from eating contaminated meat
28. Which of the following measures is MOST effective for controlling body lice?
A. Shaving all body hair
B. Washing clothing in water hotter than 60°C (140°F) followed by ironing
C. Applying insecticidal powders to the skin only
D. Isolating the patient for 2 weeks
29. A child presents with anal itching, and the parents note small rice-like segments in the child's stool. The child also has a dog and a cat pet with fleas. The most likely parasite is:
A. Hymenolepis nana
B. Taenia solium
C. Dipylidium caninum
D. Ascaris lumbricoides
30. Crab lice are most commonly transmitted via:
A. Sharing hats and combs
B. Sexual intercourse
C. Sitting on public toilet seats
D. Flea bites
Unit 6 Medically Important Cockroaches and Bugs
Welcome
Most people see a cockroach or a bed bug and feel only disgust. But as future public health professionals, you will learn to see something else: a complex organism capable of spreading disease, triggering asthma, and challenging our control efforts. Have you ever wondered why the cockroach is the most successful pest in human housing? How does a kissing bug transmit a parasite that can cause lifelong cardiac disease? Why are bed bugs making a global resurgence? By the end of this unit, you will not only identify these species under a microscope but also design rational control programs based on their biology.
Description:
This unit provides an in-depth examination of two major groups of arthropods—cockroaches (Order: Blattodea) and hemipteran bugs (Order: Hemiptera)—that directly impact human health. Students will explore the morphology, life cycles, behavior, and ecology of domestic and peridomestic cockroach species (e.g., Periplaneta americana, Blattella germanica) and true bugs such as bed bugs (Cimex lectularius) and triatomine bugs (kissing bugs). Emphasis is placed on their role as mechanical vectors of pathogens, sources of potent allergens, and direct biological vectors of Trypanosoma cruzi (Chagas disease). The unit concludes with evidence-based strategies for surveillance, integrated pest management (IPM), and public health intervention.
Learning Objectives (Goals)
By the end of this unit, students will be able to:
- Identify the major medically important species of cockroaches and bugs using taxonomic keys and morphological features.
- Compare the life cycles, habitats, and feeding behaviors of domestic cockroaches, bed bugs, and triatomine bugs.
- Explain the three primary medical impacts of cockroaches: mechanical vectoring of bacteria, production of allergic allergens, and psychological nuisance.
- Analyze the vector-pathogen relationship between triatomine bugs and Trypanosoma cruzi, including the mechanism of transmission (contamination vs. inoculation).
- Describe the clinical manifestations of Chagas disease (acute and chronic phases) and the dermatological/psychological effects of bed bug bites.
- Evaluate the limitations of common control methods (sprays, baits, foggers) and justify the use of Integrated Pest Management (IPM) for cockroach and bed bug infestations.
- Design a basic surveillance and control plan for a simulated infestation (e.g., in a low-income apartment complex).
Evaluation-Choice Questions
Instructions: Choose the best answer for each question based on the provided unit material.
1. Which order do medically important cockroaches belong to?
A) Hemiptera
B) Diptera
C) Blattodea
D) Coleoptera
2. Which of the following is a hematophagous heteropteran?
A) Seed bug
B) Aphid
C) Kissing bug (triatomine)
D) Leaf-footed bug
3. Kissing bugs (triatomines) are vectors for which disease?
A) Lyme disease
B) Malaria
C) Chagas disease (American Trypanosomiasis)
D) Dengue fever
4. The parasite transmitted by kissing bugs is:
A) Plasmodium falciparum
B) Trypanosoma brucei
C) Trypanosoma cruzi
D) Leishmania major
5. The mode of transmission for Trypanosoma cruzi by kissing bugs is termed:
A) Inoculative (via bite)
B) Stercorarian (via contaminated feces)
C) Transovarial (via eggs)
D) Aerosolized
6. Where does Trypanosoma cruzi become infective (metacyclic trypomastigotes) within the kissing bug?
A) Salivary glands
B) Midgut
C) Hindgut and rectum
D) Proventriculus
7. After being deposited on the skin near the bite, how do infective T. cruzi typically enter the human host?
A) Directly through the bite wound
B) Through mucous membranes or being rubbed into the bite wound
C) By penetrating intact skin
D) By being inhaled
8. Bed bugs belong to which family?
A) Reduviidae
B) Cimicidae
C) Blattidae
D) Culicidae
9. The scientific name for the common bed bug is:
A) Periplaneta americana
B) Blattella germanica
C) Triatoma infestans
D) Cimex lectularius
10. Bed bugs are described as being dorsoventrally flattened. This adaptation is primarily for:
A) Faster running
B) Hiding in narrow cracks and crevices
C) Improved flight
D) Camouflage
11. How do bed bugs obtain a blood meal?
A) They chew through the skin.
B) They pierce the skin with stylet-like mouthparts.
C) They secrete an enzyme that dissolves skin.
D) They scrape the skin surface.
12. The primary medical importance of bed bugs includes:
A) Vectoring T. cruzi
B) Causing asthma
C) Dermatological reactions (pruritic skin reactions) and psychological nuisance
D) Transmitting bacteria like Salmonella
13. Which statement about cockroach allergens is true?
A) They are only found in cockroach saliva.
B) Sensitization to cockroach allergens is a common trigger for asthma, especially in atopic patients.
C) Cockroach allergens only cause skin rashes.
D) Allergens are not found in their feces.
14. Cockroaches are considered mechanical vectors because they:
A) Allow a parasite to reproduce inside them
B) Transmit pathogens on their bodies and in their feces without the pathogen replicating inside them
C) Inject pathogens directly through a bite
D) Only transmit viruses
15. The egg case produced by cockroaches is called a:
A) Ootheca
B) Cocoon
C) Nymph pod
D) Sporangium
16. Which of the following is NOT a primary medical impact of cockroaches?
A) Mechanical vectoring of bacteria
B) Production of potent allergens
C) Direct transmission of Trypanosoma cruzi
D) Psychological nuisance
17. Which of the following is a common habitat for triatomine bugs?
A) Clean, modern apartments
B) Mud-walled housing and woodpiles
C) Inside sealed plastic containers
D) Fast-flowing rivers
18. What is a key limitation of using only insecticide sprays for cockroach control?
A) They are always too expensive
B) Cockroaches can develop resistance and sprays may not reach harborage areas
C) Sprays are ineffective against any cockroach species
D) Sprays only kill adult cockroaches
19. Bed bug resurgence in recent decades is thought to be due to all of the following EXCEPT:
A) Increased international travel
B) Resistance to common insecticides
C) Changes in pest control practices (e.g., less residual spraying)
D) Widespread use of anti-malarial drugs
20. The saliva of bed bugs contains anticoagulants and anesthetics. This results in:
A) Immediate sharp pain and rapid bleeding
B) The host often being unaware of the bite initially, followed by delayed pruritic reactions
C) Complete paralysis of the host
D) Transmission of T. cruzi
21. Which of the following is an example of a non-repellent insecticide used in baits against cockroaches mentioned in the text?
A) DDT
B) Hydramethylnon, fipronil, or imidacloprid
C) Pyrethrin spray
D) Bleach solution
21. What is a primary method for preventing Chagas disease transmission in endemic areas?
A) Mass vaccination campaigns
B) Improvements in housing (e.g., plastering walls) and health education
C) Widespread bed net distribution for daytime sleeping
D) Antibiotic treatment for all residents
22. The nymphs of bed bugs, compared to adults, are:
A) Larger and have fully developed wings
B) Smaller, wingless, and require a blood meal to molt
C) Herbivorous and do not feed on blood
D) Aquatic in their early stages
23. Which statement best describes the adult kissing bug's defecation habit related to T. cruzi transmission?
A) It never defecates near its host.
B) It defecates on or near the biting site, often while still feeding.
C) It only defecates after flying away from the host.
D) It defecates into the host's bloodstream directly.
24. What is a basic sanitation practice for cockroach control?
A) Leaving pet food out overnight
B) Storing food in insect-proof containers and removing debris
C) Piling wood against the house
D) Maintaining high humidity indoors
25. Why are foggers (total release aerosols) often ineffective against bed bugs?
A) They kill only eggs, not live bugs
B) The fog does not penetrate deep into cracks and crevices where bed bugs hide
C) They are too expensive for most people
D) They are repellent to bed bugs
26. Which of the following is a morphological feature of kissing bugs?
A) A rounded pronotum and short, club-like antennae
B) A triangular pronotum and stylet-like mouthparts
C) Two long cerci and no wings
D) A hard, shell-like elytra
27. Atopic patients are particularly susceptible to which medical impact of cockroaches?
A) Bacterial infection
B) Allergic sensitization and asthma
C) Direct tissue damage from bites
D) Viral hepatitis
28. What is the role of the promastigote/sphaeromastigote form of T. cruzi?
A) Infective stage found in the bug's saliva
B) Reproductive stage found in the midgut of the bug
C) Stage found only in the human heart
D) Cyst stage found in the environment
29. Control of Chagas disease primarily focuses on:
A) Vaccinating all children
B) Eliminating the triatomine bug vector and improving housing
C) Culling all wild mammals that act as reservoirs
D) Distributing mosquito nets treated with repellent
30. A public health plan for a low-income apartment complex with a severe cockroach problem should prioritize:
A) Monthly application of highly repellent foggers in all units
B) Sanitation education, sealing cracks, and targeted application of non-repellent baits and gels (IPM)
C) Evicting all residents with pets
D) Spraying the entire building with bleach daily
Unit 7. Medical important Crustaceans and Mollusks
Welcome
Welcome to the Medically Important Crustaceans and Mollusks which are most important intermediate hosts of Schistosomiasis, Fascioliasis, paragonimiasis, Dracunculiasis and so on. This section is covered in a parasitology, medical zoology, or general medicine course to for comprehensive understanding the role of crustaceans’ and mollusks’ in disease transmission. This unit focuses primarily on their roles as vectors (intermediate hosts) for human parasites, as well as direct causes of disease (e.g., toxins, allergens).
Course Description
Crustaceans are primarily aquatic arthropods. Their medical importance is almost entirely indirect—they act as intermediate hosts for helminths (parasitic worms). They do not typically bite or sting humans. Mollusks (snails, clams, mussels, slugs), on the other hand, have direct (toxins, trauma) and indirect (as intermediate hosts for trematodes) medical importance. Paragonimus westermani (lung fluke), Dracunculus medinensis (guinea worm), and Diphyllobothrium latum (fish tapeworm) are examples of parasites which use Crustaceans as primary or secondary intermediate hosts for their transmission. Similarly, Snails are Intermediate Hosts for Trematodes (Flukes). Different species of snails such as Biomphalaria spp.(Int. host of Schistosoma mansoni), Bulinus species (int. host of Schistosoma haematobium), Semisulcospira species ( Paragonimus westermani) , Parafossarulus, Oncomelania species ( Schistosoma japonicum), Lymnaea species ( Fasciola hepatica or liver fluke), Tricula / Neotricula spp. (Schistosoma mekongi) & other snails(Clonorchis sinensis ) are intermediate hosts of different fluke species
Multiple-Choice Questions for Evaluation
- The medical importance of crustaceans is almost entirely:
A) Direct, through venomous bites
B) Direct, through causing allergic reactions
C) Indirect, as intermediate hosts for helminths
D) Indirect, as definitive hosts for tapeworms - Which parasite is transmitted to humans by eating raw or undercooked freshwater crab meat containing metacercariae?
A) Dracunculus medinensis
B) Schistosoma mansoni
C) Paragonimus westermani
D) Diphyllobothrium latum - Dracunculiasis (guinea worm disease) is acquired by drinking water containing infected:
A) Freshwater shrimp
B) Copepods (e.g., Cyclops)
C) Crayfish
D) Biomphalaria snails - The lung fluke Paragonimus westermani uses all of the following as intermediate hosts EXCEPT:
A) Freshwater crabs
B) Crayfish
C) Freshwater shrimp/prawns
D) Copepods - Which snail genus is the primary intermediate host for Schistosoma mansoni, the cause of intestinal schistosomiasis?
A) Bulinus
B) Oncomelania
C) Biomphalaria
D) Lymnaea - Urinary schistosomiasis, caused by Schistosoma haematobium, is transmitted by snails of the genus:
A) Biomphalaria
B) Bulinus
C) Oncomelania
D) Parafossarulus - Oncomelania snails are the specific intermediate host for which schistosome species?
A) Schistosoma mansoni
B) Schistosoma haematobium
C) Schistosoma japonicum
D) Schistosoma mekongi - Fascioliasis (liver fluke infection) is transmitted by snails of the genus:
A) Bulinus
B) Oncomelania
C) Biomphalaria
D) Lymnaea - Which of the following is a direct (non-parasitic) medical effect caused by mollusks?
A) Transmitting Clonorchis sinensis
B) Causing trauma from sharp shells
C) Injecting venom through a stinger
D) Acting as a definitive host for tapeworms - The primary transmission route for Diphyllobothrium latum (fish tapeworm) involving copepods is:
A) Drinking water containing infected copepods (rare direct route)
B) Inhalation of copepod eggs
C) Skin penetration by copepod larvae
D) Bite of an infected copepod - Which snail family includes the genera Biomphalaria, Bulinus, and Planorbis, known for being pulmonate (air-breathing) freshwater snails?
A) Lymnaeidae
B) Planorbidae
C) Ancylidae
D) Physidae - The shell of a snail from the genus Biomphalaria is best described as:
A) Turreted (tower-shaped)
B) Cap or shield-shaped
C) Disc-shaped, with whorls in the same plane
D) Ovate and higher than wide - A turreted (tower-shaped) shell with a left-handed opening (when the spire is up) is characteristic of which snail genus?
A) Biomphalaria
B) Lymnaea
C) Bulinus
D) Oncomelania - All African freshwater snails possess:
A) Gills for breathing
B) A shell
C) A radula only in the larval stage
D) Separate sexes (dioecious) - The tongue-like, rasping structure found in the mouth of mollusks is called the:
A) Operculum
B) Mantle
C) Radula
D) Foot - Regarding reproduction, most freshwater snails of medical importance (e.g., Biomphalaria) are:
A) Dioecious (separate sexes)
B) Hermaphroditic and can self-fertilize
C) Asexual, reproducing by budding
D) Parthenogenetic (females produce eggs without mating) - The eggs of Bulinus snails are typically:
A) Circular and attached to flat surfaces
B) Elongated and wrapped around curved plant stems
C) Laid in long, gelatinous strings in open water
D) Deposited inside the tissue of fish - Snail habitats are best described as:
A) Limited to fast-flowing, cold streams
B) Only deep, large lakes
C) Almost all types of water bodies, especially those with decaying organic matter
D) Exclusively temporary rainwater pools - Which Biomphalaria species is noted as the most dominant intermediate host for S. mansoni in Rwanda?
A) B. sudanica
B) B. barthi
C) B. pfeifferi
D) B. alexandrina - Which chemical molluscicide has been used specifically to control Oncomelania snails (intermediate host of S. japonicum) in Jiangsu province, China?
A) Bleach
B) Copper sulfate
C) Niclosamide
D) Formalin - An example of biological control for Biomphalaria snails is:
A) Spraying riverbanks with niclosamide
B) Using carnivorous snails or competitor snails
C) Draining marshy areas
D) Mass drug administration with praziquantel - Which group within the genus Bulinus is noted as containing species that act as hosts in Iran, Egypt, Sudan, and Madagascar?
A) The pfeifferi group
B) The sudanica group
C) The truncatus/forskali/reticulatus group
D) The choanomphala group - The snail host for S. mansoni in the great lakes of Africa (e.g., Lake Victoria) belongs to which group of Biomphalaria?
A) The pfeifferi group
B) The sudanica group
C) The choanomphala group
D) The alexandrina group - Which of the following is an ecological method for snail control?
A) Mass chemotherapy with praziquantel
B) Spraying niclosamide on riverbanks
C) Introducing carnivorous snails
D) Removing aquatic vegetation that serves as snail food and shelter - The shell of snails from the family Ancylidae is best described as:
A) Turreted
B) Disc-shaped
C) Cap- or shield-shaped with faint coiling
D) Ovate with a large aperture - Which morphological feature is used to distinguish Bulinus snails from Biomphalaria?
A) Presence of a radula
B) Hermaphroditic reproductive system
C) Turreted shell versus disc-shaped shell
D) Ability to breathe atmospheric oxygen - Snails of the genera Lymnaea, Bulinus, and Physa share what common shell characteristic?
A) A disc-shaped shell
B) A cap-shaped shell
C) An ovate shell, higher than wide, with a large aperture
D) A shell with no visible whorls - Which of the following is NOT a primary prevention or control strategy mentioned for schistosomiasis?
A) Avoiding water contact with cercariae-infested water
B) Mass chemotherapy in high-prevalence areas (>50% infection in children)
C) Vaccination of all at-risk populations
D) Chemical control using molluscicides - Why do most aquatic snail species die during the dry season?
A) They are all eaten by predators
B) They cannot withstand desiccation (drying out)
C) They complete their life cycle and die naturally
D) They are killed by viruses that flourish in dry conditions - Which of the following correctly matches the snail genus with the disease?
a) Oncomelania - Fascioliasis
b) Lymnaea - Paragonimiasis
c) Bulinus - Urinary schistosomiasis
d) Biomphalaria - Clonorchiasis
AIMS OF THE MODULE
The aim of this module is to introduce the student to the concepts of clinical chemistry tests and their relevance to clinical diagnostics. Students will develop knowledge and an understanding of biochemical changes in different disease conditions and learn different practical techniques in clinical chemistry.