Medical Entomology MCQs 2

--- ### **Section A: Cockroaches** **1.** Which of the following best describes the role of cockroaches in disease transmission?A. Biological vectorsB. Mechanical vectorsC. Definitive hostsD. Intermediate hosts**Correct answer:** B. Mechanical vectors**Explanation:** Cockroaches mechanically transmit pathogens through contamination of food, utensils, and surfaces. **2.** Which species of cockroach is most commonly found in hospitals and food establishments?A. Periplaneta americanaB. Blatta orientalisC. Blattella germanicaD. Blaberus giganteus**Correct answer:** C. Blattella germanica**Explanation:** The German cockroach is the most common domestic species, especially in warm indoor environments. **3.** Cockroaches are important in medical entomology mainly because:A. They bite humans causing lesionsB. They act as intermediate hosts for PlasmodiumC. They mechanically carry pathogens on their bodiesD. They inject toxins through bites**Correct answer:** C. They mechanically carry pathogens on their bodies**Explanation:** Their legs and body surfaces can carry bacteria, fungi, and parasites from contaminated areas. **4.** The ootheca of cockroaches refers to:A. Larval stageB. Egg caseC. Adult exoskeletonD. Feeding organ**Correct answer:** B. Egg case**Explanation:** Female cockroaches produce oothecae that contain multiple eggs, protecting them until hatching. **5.** A notable feature of cockroaches relevant to control is:A. Their short life cycle makes control easyB. They live only outdoorsC. They hide in cracks and crevices making control difficultD. They depend on a single food source**Correct answer:** C. They hide in cracks and crevices making control difficult**Explanation:** Their nocturnal and cryptic behavior complicates elimination efforts. --- ### **Section B: Non-Biting and Myiasis-Producing Flies** **6.** Which genus is commonly associated with facultative myiasis in humans?A. GlossinaB. MuscaC. CalliphoraD. Culex**Correct answer:** C. Calliphora**Explanation:** Blowflies such as Calliphora can cause facultative myiasis in neglected wounds. **7.** Musca domestica is medically important because:A. It transmits malariaB. It serves as an intermediate host for filarial wormsC. It mechanically transmits pathogensD. It produces larval toxins**Correct answer:** C. It mechanically transmits pathogens**Explanation:** The common housefly carries pathogens on its body and regurgitates contaminated material. **8.** The term “accidental myiasis” refers to:A. Larval infestation occurring in tissues intentionallyB. Larvae accidentally ingested or entering orificesC. Obligatory infestation by larvaeD. Vector transmission by flies**Correct answer:** B. Larvae accidentally ingested or entering orifices**Explanation:** It occurs when fly eggs or larvae enter tissues or cavities unintentionally. **9.** The screwworm fly (Cochliomyia hominivorax) causes:A. Facultative myiasis only in animalsB. Obligatory myiasis in living tissuesC. Mechanical transmission of bacteriaD. Malaria**Correct answer:** B. Obligatory myiasis in living tissues**Explanation:** Its larvae actively invade healthy tissues, causing severe lesions. **10.** The housefly transmits pathogens mainly through:A. SalivaB. Regurgitation and fecal contaminationC. Blood feedingD. Vertical transmission**Correct answer:** B. Regurgitation and fecal contamination**Explanation:** Flies vomit and defecate on food, contaminating it with microbes. **11.** Which fly species is known as the “tumbu fly” in Africa?A. Dermatobia hominisB. Cordylobia anthropophagaC. Stomoxys calcitransD. Musca domestica**Correct answer:** B. Cordylobia anthropophaga**Explanation:** This species causes cutaneous myiasis in humans and animals in tropical Africa. **12.** Cordylobia anthropophaga infestation typically presents as:A. Painless ulcersB. Boil-like lesions with central breathing poresC. Severe systemic illnessD. Diffuse rashes**Correct answer:** B. Boil-like lesions with central breathing pores**Explanation:** Larvae develop under the skin causing furuncular lesions with visible openings. **13.** Dermatobia hominis transmits its larvae to humans through:A. Direct oviposition on skinB. Using other insects as carriersC. Mechanical contamination of foodD. Blood meals**Correct answer:** B. Using other insects as carriers**Explanation:** Eggs are attached to blood-sucking insects; larvae enter skin when the insect feeds. **14.** Myiasis can be prevented by:A. Allowing flies to access woundsB. Wearing open clothesC. Covering wounds and maintaining hygieneD. Avoiding bathing**Correct answer:** C. Covering wounds and maintaining hygiene**Explanation:** Good personal and wound hygiene prevents fly oviposition. **15.** Facultative myiasis occurs when:A. Flies obligatorily invade living tissueB. Flies lay eggs in necrotic tissue but can survive without itC. Flies act as biological vectorsD. Larvae are ingested accidentally**Correct answer:** B. Flies lay eggs in