Medical Bacteriology and Parasitology End of Year 2024/2025

Question 1

Fish are second intermediate hosts of?

Accepted Answer

Clonorchis sinensis — Fish are the second intermediate host of Clonorchis sinensis (snails are the first). ---

Question 2

Which of the following secretes defensive secretions to cause irritation on human skin?

Accepted Answer

Millipedes — Millipedes secrete defensive fluids that irritate the skin. Centipedes bite. ---

Question 3

Holometabolous insects have?

Accepted Answer

4 life stages — Holometabolous insects pass through four stages: egg, larva, pupa and adult. ---

Question 4

Which of the following transmits parasites for river blindness?

Accepted Answer

Simulium species — Simulium (blackflies) transmit Onchocerca volvulus, the cause of river blindness. ---

Question 5

Presence of triatomine bugs could predispose the population to?

Accepted Answer

Chagas disease — Triatomine bugs transmit Trypanosoma cruzi, which causes Chagas disease. ---

Question 6

Which of the following insects are commonly found in Latin America?

Accepted Answer

Triatomine bugs — Triatomine bugs occur in Latin America. ---

Question 7

Pruritus can be best diagnosed for?

Accepted Answer

Sarcoptes scabiei — Sarcoptes scabiei (scabies) causes intense itching (pruritus). ---

Question 8

If you found lice eggs (nits) in someone's clothing, what species would they most likely be from?

Accepted Answer

Pediculus humanus — Nits in clothing belong to body lice, Pediculus humanus. ---

Question 9

Which of the following is odd one out in terms of transmission?

Accepted Answer

Thelazia species — Thelazia (eye worm) is transmitted by flies. The others spread by the faecal-oral route. ---

Question 10

Which one of the following is larviparous?

Accepted Answer

Glossina gambiense — Glossina (tsetse flies) are larviparous: they give birth to a mature larva. ---

Question 11

Argasid ticks have?

Accepted Answer

Multiple hosts — Argasid (soft) ticks feed on multiple hosts, with several nymphal stages. ---

Question 12

Ixodid ticks have nymphal stages.

Accepted Answer

One — Ixodid (hard) ticks have a single nymphal stage. ---

Question 13

Traps for Glossina species are composed of?

Accepted Answer

Black and blue colors — Blue and black cloth traps attract tsetse flies. ---

Question 14

Hepatitis B virus has been associated with?

Accepted Answer

Cimex species — Bed bugs (Cimex) have been linked with hepatitis B virus. ---

Question 15

Lowenstein Jensen media is used to isolate?

Accepted Answer

Mycobacterium tuberculosis — Lowenstein-Jensen medium is used to grow Mycobacterium tuberculosis. ---

Question 16

All of the following statements regarding Clostridium perfringens are correct EXCEPT

Accepted Answer

It is the most common cause of antibiotic-associated diarrhea — C. difficile, not C. perfringens, is the main cause of antibiotic-associated diarrhoea, so statement D is the incorrect one. ---

Question 17

Motility of the bacteria can be observed by

Accepted Answer

Both "A" and "B" — Motility can be seen by the hanging drop method and by soft agar. ---

Question 18

The drug of choice to treat this patient's infection (Question 23) is

Accepted Answer

Trimethoprim-sulfamethoxazole — Trimethoprim-sulfamethoxazole is the drug of choice for Nocardia. ---

Question 19

can cause food INTOXICATION?

Accepted Answer

Staphylococcus aureus — Staphylococcus aureus enterotoxin causes food intoxication (preformed toxin). ---

Question 20

Helicobacter pylori possesses that helps to neutralize stomach acid (HCl).

Accepted Answer

Urease — H. pylori produces urease, which makes ammonia and neutralises stomach acid. ---

Question 21

The primary mechanism in the pathogenesis of the boy's disease (Question 27) is

Accepted Answer

Inactivation of elongation factor 2 — Diphtheria toxin inactivates elongation factor 2. ---

Question 22

Which of the following aerobic gram-positive bacilli is modified acid-fast positive?

Accepted Answer

Nocardia brasiliensis — Nocardia is the aerobic gram-positive bacillus that is modified acid-fast positive. ---

Question 23

A biochemical reaction that is useful in the identification of the causative agent of the infection in question 30 is

Accepted Answer

Production of H2S — Erysipelothrix produces H2S, which helps identify it. ---

Question 24

Drug of choice for treatment of mycoplasma infection are

Accepted Answer

A and B — Macrolides (erythromycin) and tetracyclines are both used for Mycoplasma. ---

Question 25

Patient with presence of penile chancre should be advised by physician to

Accepted Answer

Perform dark field microscope for treponemes — A penile chancre suggests primary syphilis. Dark-field microscopy shows the motile treponemes.

Medical Bacteriology and Parasitology End of Year 2024/2025

Questions, Answers & Explanations