37 Year 2: Parasitology exam questions on Medical Bacteriology And Parasitology End Year 2024/2025 for medical students. Includes MCQs, answers, explanations an
This MCQ set contains 37 questions on Medical Bacteriology And Parasitology End Year 2024/2025 in the Year 2: Parasitology unit. Each question includes the correct answer and a detailed explanation for active recall and exam preparation.
Correct answer: A – Echinostoma ilocaanum
Fish serve as the second intermediate host for Clonorchis sinensis (Chinese liver fluke). Humans get infected by eating raw or undercooked fish containing the parasite's metacercariae. ---
Correct answer: A – Millipedes
Millipedes have defensive glands that secrete irritating chemicals (benzoquinones, hydrogen cyanide) causing skin burns and discoloration. Centipedes bite rather than secrete defensive substances. ---
Correct answer: A – 2 life stages
Holometabolous insects undergo complete metamorphosis with four stages: egg → larva → pupa → adult. Examples include mosquitoes, flies, and beetles. ---
Correct answer: A – Culex species
Simulium species (blackflies) are the vectors of Onchocerca volvulus, causing river blindness (onchocerciasis). They breed in fast-flowing rivers. ---
Correct answer: A – DDT
Bendiocarb is a carbamate insecticide that inhibits acetylcholinesterase, affecting GABA neurotransmission. DDT and permethrin target sodium channels instead. ---
Correct answer: A – Sleeping sickness
Triatomine bugs (kissing bugs) transmit Trypanosoma cruzi, which causes Chagas disease. They defecate while feeding, and parasites enter through the bite wound or mucous membranes. ---
Correct answer: A – Sleeping sickness
Forested areas harbor sandflies (Phlebotomus/Lutzomyia species) that transmit Leishmania parasites. Forest ecosystems provide ideal habitats for sandfly vectors and animal reservoirs. ---
Correct answer: A – Glossina species
Triatomine bugs are endemic to Latin America where they transmit Chagas disease. Glossina species (tsetse flies) are found only in sub-Saharan Africa. ---
Correct answer: A – Sarcoptes scabiei
Sarcoptes scabiei (scabies mite) burrows into skin causing intense pruritus (itching), especially at night due to mite activity and allergic reaction to mite proteins. ---
Correct answer: A – Crab lice
Pediculus humanus (body lice) live and lay eggs in clothing seams, not on the body. Pediculus capitis (head lice) attach eggs to hair shafts, not clothing. ---
Correct answer: A – Vibrio cholerae
Thelazia species (eye worm) is transmitted by flies (mechanical vectors), while the others are transmitted via fecal-oral route through contaminated water/food. ---
Correct answer: A – Phlebotomus species
Glossina species (tsetse flies) are larviparous - they give birth to live larvae rather than laying eggs. The larva immediately pupates after birth. ---
Correct answer: A – One host
Argasid (soft) ticks are multi-host ticks that feed quickly (minutes to hours) on different hosts throughout their life stages, unlike ixodid ticks. ---
Correct answer: A – One
Ixodid (hard) ticks have a single nymphal stage in their life cycle: egg → larva → nymph → adult. This is standard for hard ticks. ---
Correct answer: A – Black and white colors
Aedes mosquitoes are attracted to contrasting black and white patterns. Ovitraps and BG-Sentinel traps use this color combination for effective Aedes surveillance and control. ---
Correct answer: A – Black and white colors
Tsetse flies (Glossina species) are attracted to black and blue colors. Biconical traps and targets use these colors for effective tsetse fly control. ---
Correct answer: A – Simulium species
Blackwater fever is a severe complication of falciparum malaria (transmitted by Anopheles mosquitoes), characterized by massive intravascular hemolysis causing dark urine. ---
Correct answer: A – Cimex species
Cimex species (bed bugs) have been studied for potential mechanical transmission of Hepatitis B virus, though their role remains controversial and not definitively proven. ---
Correct answer: A – It is routinely available for all citizens of the United States
Newer recombinant protective antigen vaccines have demonstrated good safety and efficacy in trials. The current AVA vaccine requires multiple doses and has tolerability issues. ---
Correct answer: A – Streptococcus species
Lowenstein-Jensen medium is an egg-based selective medium specifically designed for culturing Mycobacterium tuberculosis and other mycobacteria, which grow slowly and require special nutrients. ---
Correct answer: A – It produces an enterotoxin
Clostridioides difficile (not C. perfringens) is the most common cause of antibiotic-associated diarrhea. C. perfringens causes food poisoning and gas gangrene. ---
Correct answer: A – Hanging drop method
Bacterial motility is observed using hanging drop method (direct microscopic visualization) and soft agar method (growth pattern spreading from stab line). Pour plate is for colony counting. ---
Correct answer: A – Actinomyces israelii
The patient is immunocompromised (chemotherapy), has pulmonary infection with brain abscesses, and shows branching gram-positive rods that are partially acid-fast - all classic for Nocardia species, which disseminate to the brain. ---
Correct answer: A – Penicillin G
Trimethoprim-sulfamethoxazole (TMP-SMX) is the first-line treatment for Nocardia infections. Treatment duration is prolonged (6-12 months) due to tendency for relapse. ---
Correct answer: A – Staphylococcus aureus
Staphylococcus aureus produces preformed enterotoxins in food, causing food intoxication (rapid onset 1-6 hours). Salmonella and E. coli cause food infection (longer incubation, bacteria must multiply). ---