Practise Medical Entomology MCQs 2 with organized questions, answers and explanations for focused medical exam revision. Kenya, Africa and global revision.
--- EXAM 1: MEDICAL BACTERIOLOGY AND PARASITOLOGY Unit Code: MBMM 3300 Date: Tuesday, 15th July 2025 Time: 8:00 AM Duration: 2 Hours SECTION A: MCQs (35 Marks) Q1. Fish are second intermediate hosts of? A. Fasciola hepatica B. Hymenolepis nana C. Clonorchis sinensis D. Echinostoma ilocanum E. Fasciolopsis buski Answer: C. Clonorchis sinensis Explanation: Clonorchis sinensis uses snails as first intermediate host and freshwater fish as second intermediate host, where metacercariae encyst. Q2. Which of the following secretes defensive secretions to cause irritation on human skin? A. Centipedes B. Necator americanus C. Millipedes D. Enterobius vermicularis E. All of the above Answer: C. Millipedes Explanation: Millipedes release defensive fluids (e.g., benzoquinones) that irritate skin on contact; centipedes envenomate by biting instead. Q3. Holometabolous insects have? A. 5 life stages B. 1 life stage C. 2 life stages D. 4 life stages E. 3 life stages Answer: D. 4 life stages Explanation: Complete metamorphosis proceeds through egg, larva, pupa, and adult. Q4. Which of the following transmits parasites for river blindness? A. Culex species B. Toxorhynchintinae species C. Simulium species D. Chrysops species E. All of the above Answer: C. Simulium species Explanation: Simulium (blackfly) transmits Onchocerca volvulus, causing river blindness. Q5. Which insecticide targets GABA in its action? A. Bendiocarb B. Permethrin C. Malathion D. DDT E. DEET Answer: No listed option is correct. Explanation: DDT and permethrin act on voltage-gated sodium channels; bendiocarb and malathion inhibit acetylcholinesterase. None of the listed agents is the expected GABA-gated chloride-channel antagonist. Q6. Presence of triatomine bugs could predispose the population to? A. Malaria B. Sleeping sickness C. River blindness D. Chagas disease E. Leishmaniasis Answer: D. Chagas disease Explanation: Triatomine bugs transmit Trypanosoma cruzi, causing Chagas disease. Q7. People living in forested areas like Arabuko Sokoke are at risk of? A. Encephalitis B. Malaria C. Sleeping sickness D. River blindness E. Leishmaniasis Answer: C. Sleeping sickness Explanation: Arabuko Sokoke is a tsetse fly (Glossina) habitat; tsetse transmits Trypanosoma brucei. Q8. Which of the following insects are commonly found in Latin America? A. Chrysops species B. Glossina species C. Cimex species D. Triatomine bugs E. Steam bugs Answer: D. Triatomine bugs Explanation: Vectors of Chagas disease, widely distributed across Latin America. Q9. Pruritis can be best diagnosed for? A. Blattella species B. Leptothrombidium species C. Pediculus species D. Pthirus species E. Sarcoptes scabiei Answer: E. Sarcoptes scabiei Explanation: Scabies causes intense pruritis from hypersensitivity to mites/eggs/feces. Q10. If you found lice eggs (nits) in someone's clothing, what species would they most likely be from? A. Pediculus capitis B. Crab lice C. Pthirus species D. Pediculus humanus E. All of the above Answer: D. Pediculus humanus Explanation: The body louse lays eggs in clothing seams, unlike head or crab lice. Q11. Which of the following is odd one out in terms of transmission? A. Rotavirus B. Entamoeba histolytica C. Thelazia species D. Vibrio cholera E. None of the above Answer: E. None of the above (as marked) — functionally C. Thelazia species is the outlier Explanation: The other three are fecal-oral pathogens; Thelazia is transmitted by flies directly to the eye. Q12. Which one of the following is larviparous? A. Dermacentos species B. Triatomine bugs C. Phlebotomus species D. Glossina gambiense E. Lutzomyia species Answer: D. Glossina gambiense Explanation: Tsetse flies show adenotrophic viviparity, nourishing a single larva internally. Q13. Argasid ticks have? A. Two hosts B. Four hosts C. One host D. Multiple hosts E. Three hosts Answer: D. Multiple hosts Explanation: Soft ticks feed briefly and repeatedly on multiple hosts. Q14. Ixodid ticks have nymphal stage(s). A. Multiple B. Two C. One D. Four E. Three Answer: C. One Explanation: Hard ticks have a single nymphal stage. Q15. Traps for Aedes mosquitoes are composed of? A. White only B. White and blue colors C. Black only D. Black and blue colors E. Black and white colors Answer: D. Black and blue colors Explanation: Aedes are attracted to dark contrasting colors. Q16. Traps for Glossina species are composed of? A. White and blue colors B. Black and blue colors C. Black only D. White only E. Black and white colors Answer: B. Black and blue colors Explanation: Tsetse traps use blue and black cloth panels. Q17. Black water disease is due to presence of in the environment. A. Musca species B. Culicoides species C. Lutzomyia species D. Anopheles species E. Simulium species Answer: E. Simulium species (as marked; note the classic medical definition of blackwater fever links to Anopheles/malaria — flag with your lecturer) Q18. Hepatitis B virus has been associated with? A. Steam bugs B. Tabanids species C. Xenopsy