Medical Entomology Cat Practice – 50 MCQs | Kenya MBChB

50 Year 2: Parasitology exam questions on Medical Entomology Cat Practice for medical students. Includes MCQs, answers, explanations and written questions. Samp

This MCQ set contains 50 questions on Medical Entomology Cat Practice in the Year 2: Parasitology unit. Each question includes the correct answer and a detailed explanation for active recall and exam preparation.

Q1: Question 1 A mosquito species that prefers to feed on humans indoors and rests inside houses after feeding would be classified as

  1. A. Exophagic and exophilic
  2. B. Endophagic and endophilic
  3. C. Anthropophilic and zoophilic
  4. D. Exophagic and endophilic
  5. E.

Correct answer: B – Endophagic and endophilic

Endophagic refers to feeding indoors, while endophilic refers to resting indoors after blood meal digestion. This combination makes a vector particularly dangerous for indoor transmission of diseases like malaria.

Q2: Question 2 Which of the following best describes the strategy of zooprophylaxis in vector control?

  1. A. Using insecticides to kill vectors that feed on animals
  2. B. Diverting vectors to feed on animals instead of humans
  3. C. Vaccinating animals against vector-borne diseases
  4. D. Using animal blood to attract vectors to traps

Correct answer: B – Diverting vectors to feed on animals instead of humans

Zooprophylaxis involves diverting zoophilic vectors away from humans by providing alternative animal hosts, thereby reducing human-vector contact and disease transmission.

Q3: Question 3 The term "hemimetabolous" in reference to tick development means

  1. A. Complete metamorphosis with pupal stage
  2. B. Incomplete metamorphosis without pupal stage
  3. C. Development that occurs inside the host
  4. D. Development that requires multiple hosts
  5. E. This is seen in ticks, bedbugs, and cockroaches.

Correct answer: B – Incomplete metamorphosis without pupal stage

Hemimetabolous development is incomplete metamorphosis proceeding through egg, nymph, and adult stages without a pupal stage. This is seen in ticks, bedbugs, and cockroaches.

Q4: Nidicolous behavior in arthropod vectors refers to

  1. A. Feeding during nighttime only
  2. B. Remaining close to the host's resting place
  3. C. Migrating long distances from breeding sites
  4. D. Feeding on multiple host species
  5. E. Soft ticks (Argasida

Correct answer: B – Remaining close to the host's resting place

Nidicolous behavior means the vector stays near the host's home or resting area. Soft ticks (Argasidae) exhibit this behavior, while hard ticks (Ixodidae) are non-nidicolous and move away from the host's dwelling.

Q5: Question 5 Which characteristic distinguishes diurnal from nocturnal vectors?

  1. A. Feeding preference for human versus animal blood
  2. B. Time of day when they are most active
  3. C. Location of feeding (indoor versus outdoor)
  4. D. Type of disease they transmit
  5. E. g., Aedes aegypti), while nocturnal vectors are active at night (e.g., Anopheles mosquitoes, cockroaches). This affects control strategies and persona

Correct answer: B – Time of day when they are most active

Diurnal vectors are active during the day (e.g., Aedes aegypti), while nocturnal vectors are active at night (e.g., Anopheles mosquitoes, cockroaches). This affects control strategies and personal protection measures.

Q6: Question 6 A "questing behavior" in ticks refers to

  1. A. Searching for water sources
  2. B. Climbing vegetation and extending limbs to attach to passing hosts
  3. C. Migrating to new geographic areas
  4. D. Feeding on multiple hosts sequentially

Correct answer: B – Climbing vegetation and extending limbs to attach to passing hosts

Questing is the characteristic behavior of hard ticks where they climb up vegetation and extend their forelegs to attach to warm-blooded animals that pass by. This is how they locate and attach to potential hosts.

Q7: Question 7 In the context of vector-borne diseases, what does "mechanical transmission" mean?

  1. A. The pathogen multiplies within the vector
  2. B. The pathogen is physically carried by the vector without multiplication
  3. C. The pathogen is transmitted through vector saliva
  4. D. The pathogen requires the vector for part of its life cycle
  5. E. g., legs, mouthparts) without the pathogen undergoing development or multiplication in the vector. Houseflies mechanically transmit many pathogens.

Correct answer: B – The pathogen is physically carried by the vector without multiplication

Mechanical transmission occurs when a vector carries a pathogen on its body parts (e.g., legs, mouthparts) without the pathogen undergoing development or multiplication in the vector. Houseflies mechanically transmit many pathogens.

Q8: Question 8 The term "exophagic" describes a vector that

  1. A. Feeds on blood outdoors
  2. B. Rests outdoors after feeding
  3. C. Feeds on plant nectar
  4. D. Feeds on multiple host species

Correct answer: A – Feeds on blood outdoors

Exophagic means feeding outdoors. This is important for vector control because exophagic vectors are less affected by indoor residual spraying (IRS) compared to endophagic vectors.

Q9: Question 9 Trans-ovarial transmission in vectors refers to

  1. A. Transmission from male to female during mating
  2. B. Transmission from infected female to her offspring through eggs
  3. C. Transmission between different developmental stages
  4. D. Transmission through contaminated surfaces

Correct answer: B – Transmission from infected female to her offspring through eggs

Trans-ovarial (vertical) transmission occurs when an infected female vector passes the pathogen to her eggs, resulting in infected offspring. This is seen in soft ticks transmitting Borrelia (relapsing fever).

Q10: Question 10 Which of the following vectors exhibits incomplete metamorphosis?

  1. A. Mosquitoes
  2. B. Houseflies
  3. C. Cockroaches
  4. D. Butterflies
  5. E. Mosquitoes and houseflies undergo complete metamorphosis (egg → larva → pupa → adult). --- SECTION B: COCKROACHES & BEDBUGS (Questions 11-16)

Correct answer: C – Cockroaches

Cockroaches, ticks, and bedbugs undergo incomplete metamorphosis (egg → nymph → adult) without a pupal stage. Mosquitoes and houseflies undergo complete metamorphosis (egg → larva → pupa → adult). --- SECTION B: COCKROACHES & BEDBUGS (Questions 11-16)

Q11: Question 11 Which cockroach species is commonly known as the German cockroach?

  1. A. Periplaneta americana
  2. B. Blattella germanica
  3. C. Blatta orientalis
  4. D. Supella longipalpa
  5. E. Periplaneta americana is the American cockroach, and Blatta orientalis is the Oriental cockroach.

Correct answer: B – Blattella germanica

Blattella germanica is the German cockroach, one of the most common household pest cockroaches worldwide. Periplaneta americana is the American cockroach, and Blatta orientalis is the Oriental cockroach.

Q12: The primary medical importance of cockroaches includes all of the following EXCEPT

  1. A. Mechanical transmission of
  2. B. coli
  3. C. Causing allergies and asthma through body parts
  4. D. Biological vector of malaria
  5. E. Contaminating food with partially digested material

Correct answer: D – Biological vector of malaria

Cockroaches are NOT biological vectors of malaria. They are mechanical vectors that transmit bacteria like E. coli and cause allergies through inhalation of their body parts and feces. Malaria is transmitted by Anopheles mosquitoes.

Q13: Question 13 What is the rostrum count characteristic of bedbugs?

  1. A. Three-segmented rostrum
  2. B. Five-segmented rostrum
  3. C. Seven-segmented rostrum
  4. D. Single unsegmented rostrum
  5. E. have a five-segmented rostrum (proboscis) used for piercing skin and taking blood meals. This is a key morphological feature for identification.

Correct answer: B – Five-segmented rostrum

Bedbugs (Cimicidae) have a five-segmented rostrum (proboscis) used for piercing skin and taking blood meals. This is a key morphological feature for identification.

Q14: Question 14 Bedbugs are primarily active during

  1. A. Dawn and dusk
  2. B. Daytime
  3. C. Nighttime
  4. D. Throughout the day

Correct answer: C – Nighttime

Bedbugs are nocturnal feeders with an aversion to light. They hide in cracks and crevices during the day and emerge at night to feed on sleeping hosts.

Q15: Question 15 Which disease is mechanically transmitted by bedbugs?

  1. A. Dengue fever
  2. B. Anthrax (Bacillus anthracis)
  3. C. Typhoid fever
  4. D. Cholera
  5. E. and may transmit filarial nematodes.

Correct answer: B – Anthrax (Bacillus anthracis)

Bedbugs can mechanically transmit Bacillus anthracis (anthrax). They are also associated with transmission of Borrelia (Lyme disease) and may transmit filarial nematodes.

Q16: Question 16 Boric acid powder works as a cockroach control agent primarily through

  1. A. Neurotoxicity affecting the nervous system
  2. B. Contact and stomach poison causing dehydration
  3. C. Suffocation by blocking spiracles
  4. D. Repelling cockroaches from treated areas

Correct answer: B – Contact and stomach poison causing dehydration

Boric acid acts as both a contact and stomach poison. It adheres to the cockroach's body, is ingested during grooming, and causes dehydration by damaging the exoskeleton and digestive system. --- SECTION C: FLIES - MUSCIDAE, FANIDAE & TABANIDAE (Questions 17-24)

Q17: Question 17 Which housefly species is known as the "stable fly" and is a painful biter?

  1. A. Musca domestica
  2. B. Muscina stabulans
  3. C. Stomoxys calcitrans
  4. D. Fannia species
  5. E. , which only feeds on liquid organic matter, Stomoxys is a true biter.

Correct answer: C – Stomoxys calcitrans

Stomoxys calcitrans (stable fly) is a biting fly that takes blood meals and causes painful bites. Unlike the common housefly (Musca domestica), which only feeds on liquid organic matter, Stomoxys is a true biter.

Q18: Question 18 Houseflies (Musca domestica) are primarily important as

  1. A. Biological vectors requiring pathogen development
  2. B. Mechanical vectors carrying pathogens on body parts
  3. C. Intermediate hosts for parasites
  4. D. Direct causative agents of disease

Correct answer: B – Mechanical vectors carrying pathogens on body parts

Houseflies are mechanical vectors that carry pathogens (bacteria, viruses, protozoa, helminth eggs) on their body parts, especially legs and mouthparts, contaminating food and surfaces without the pathogen multiplying in the fly.

Q19: Obligate myiasis differs from facultative myiasis in that obligate myiasis

  1. A. Can occur in both living and dead tissue
  2. B. Requires living tissue to complete the larval life cycle
  3. C. Only occurs through accidental ingestion
  4. D. Does not cause any medical problems
  5. E. g., screwworm flies). Facultative myiasis can occur in living or dead tissu

Correct answer: B – Requires living tissue to complete the larval life cycle

Obligate myiasis requires living tissue for larval development (e.g., screwworm flies). Facultative myiasis can occur in living or dead tissue. Accidental myiasis occurs when larvae are ingested by chance.

Q20: Question 20 In maggot therapy using Lucilia sericata, the larvae are used to

  1. A. Stimulate immune response
  2. B. Deliver antibiotics to infected tissue
  3. C. Debride dead and necrotic tissue from wounds
  4. D. Prevent bacterial colonization through competition

Correct answer: C – Debride dead and necrotic tissue from wounds

Sterile maggots of Lucilia sericata selectively feed on dead, necrotic tissue (debridement) while leaving healthy tissue intact. This cleans wounds and promotes healing, a practice called maggot debridement therapy.

Q21: Question 21 Horse flies (Tabanidae) are primarily active during

  1. A. Night time
  2. B. Dawn and dusk
  3. C. Daytime, especially in bright sunlight
  4. D. Cloudy, overcast conditions
  5. E. and prefer bright, sunny conditions. They are persistent biters and are attracted to movement and dark objects, making them particularly troublesome d

Correct answer: C – Daytime, especially in bright sunlight

Horse flies are diurnal (day-active) and prefer bright, sunny conditions. They are persistent biters and are attracted to movement and dark objects, making them particularly troublesome during daytime outdoor activities.

Q22: Question 22 Which genus of horse flies is attracted by smoke?

  1. A. Tabanus
  2. B. Chrysops
  3. C. Haematopota
  4. D. All Tabanidae
  5. E. This is an unusual characteristic that can be important in certain environments.

Correct answer: B – Chrysops

Chrysops (deer flies) are specifically noted to be attracted by smoke, unlike other Tabanidae genera. This is an unusual characteristic that can be important in certain environments.

Q23: Question 23 Horse flies are involved in the mechanical transmission of all EXCEPT

  1. A. Bacillus anthracis (Anthrax)
  2. B. Francisella tularensis (Tularemi
  3. C.
  4. D. Borrelia burgdorferi (Lyme diseas
  5. E.
  6. F. Plasmodium falciparum (Malari
  7. G.

Correct answer: F – Plasmodium falciparum (Malari

Horse flies mechanically transmit anthrax, tularemia, and Lyme disease pathogens. Malaria is biologically transmitted by Anopheles mosquitoes, not mechanically by horse flies.

Q24: UV light traps for housefly control work by

  1. A. Repelling flies away from treated areas
  2. B. Attracting flies with UV light then electrocuting them
  3. C. Sterilizing flies that approach the light
  4. D. Disrupting fly navigation systems
  5. E. When flies approach, they are electrocuted by an electric grid, providing a non-chemical control metho

Correct answer: B – Attracting flies with UV light then electrocuting them

UV light traps (insectocutors) attract flies using ultraviolet light, which flies find attractive. When flies approach, they are electrocuted by an electric grid, providing a non-chemical control method. --- SECTION D: TICKS - IXODIDAE & ARGASIDAE (Questions 25-34)

Q25: Question 25 Hard ticks (Ixodidae) differ from soft ticks (Argasidae) in that hard ticks

  1. A. Have multiple nymphal stages
  2. B. Are nidicolous and stay near host dwellings
  3. C. Remain attached to hosts for longer periods (1-4 weeks)
  4. D. Feed quickly and drop off within hours
  5. E. Soft ticks feed quickly (minutes to hours) and drop off. Hard ticks are non-nidicolous (move away from host's home), while soft ticks are nidicolous.

Correct answer: C – Remain attached to hosts for longer periods (1-4 weeks)

Hard ticks attach to hosts for extended periods (1-4 weeks) to feed. Soft ticks feed quickly (minutes to hours) and drop off. Hard ticks are non-nidicolous (move away from host's home), while soft ticks are nidicolous.

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