Question 1

Which of the following best describes the function of the blood-brain barrier in the nervous system?

Accepted Answer

It restricts the passage of certain substances from the blood into the CNS, but can be compromised during inflammation.

Question 2

A patient presents with fever, headache, stiff neck, and a non-fading purple rash. Gram stain of CSF reveals Gram-negative diplococci. Which organism is most likely responsible?

Accepted Answer

Neisseria meningitidis

Question 3

Which of the following is a key reason why bacterial meningitis is more severe than viral meningitis?

Accepted Answer

Bacterial meningitis often involves endotoxin or cell wall release, causing shock and inflammation.

Question 4

Which test is used to identify the presence of a bacterial capsule in Haemophilus influenzae meningitis?

Accepted Answer

Quellung reaction

Question 5

A 3-year-old child develops meningitis. The causative agent is a Gram-negative aerobic rod requiring X and V factors for growth. Which vaccine could have prevented this infection?

Accepted Answer

HiB vaccine

Question 6

Which of the following statements about Listeria monocytogenes is TRUE?

Accepted Answer

It can cross the placenta and cause stillbirth.

Question 7

A patient with a deep puncture wound develops muscle spasms and lockjaw. Which of the following best explains the pathogenesis?

Accepted Answer

The neurotoxin blocks the relaxation pathway in muscles.

Question 8

Which food is most commonly associated with infant botulism?

Accepted Answer

Honey

Question 9

Which of the following is the most effective method for preventing botulism in home-canned foods?

Accepted Answer

Adding nitrites to prevent endospore germination

Question 10

Which of the following statements about leprosy is correct?

Accepted Answer

It can be noncontagious with sulfone drug treatment.

Question 11

A patient presents with loss of sensation in skin areas and a positive lepromin test. Which form of leprosy is this?

Accepted Answer

Tuberculoid (neural) form

Question 12

Which of the following best describes the mechanism of action of botulinum toxin?

Accepted Answer

It blocks the release of acetylcholine at the neuromuscular junction.

Question 13

Which of the following is a distinguishing feature of viral meningitis compared to bacterial meningitis?

Accepted Answer

Viral meningitis is usually milder and harder to treat.

Question 14

Which of the following vaccines is a live attenuated vaccine that provides lifelong immunity against poliomyelitis?

Accepted Answer

Sabin vaccine

Question 15

A patient is bitten by a wild animal and later develops hydrophobia and agitation. What is the most appropriate post-exposure treatment?

Accepted Answer

Rabies immune globulin (RIG) and HDCV vaccine

Question 16

Which of the following is a common route of transmission for arboviral encephalitis?

Accepted Answer

Mosquito bites

Question 17

A pregnant woman contracts Zika virus. What is the most significant risk to her fetus?

Accepted Answer

Microcephaly

Question 18

Which of the following is the most effective way to prevent prion diseases in surgical settings?

Accepted Answer

Sterilization with NaOH and extended autoclaving at $$134^\circC$$

Question 19

A patient presents with chronic headaches, fever, and progressive CNS deterioration. Blood smear reveals flagellated protozoa. What is the most likely diagnosis?

Accepted Answer

African trypanosomiasis

Question 20

Which of the following statements about prion diseases is correct?

Accepted Answer

They are caused by abnormally folded proteins and are very difficult to destroy.

Microbial Diseases of the Nervous System: Bacterial, Viral, Fungal, Protozoan, and Prion Infections

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