Q: Which equation best represents the time before onset of botulism symptoms ($$t) as a $$function of dose size ($$d$$), given that onset ranges from 12 to 72 hours?

$$t = 12 + (72 - 12) \times \frac{1}{d}$$

Question 1

Which of the following statements about the normal biota of the nervous system is correct?

Accepted Answer

There is no normal biota in either the central or peripheral nervous system.

Question 2

A patient presents with headache, stiff neck, fever, and photophobia. A lumbar puncture reveals bacteria in the cerebrospinal fluid. Which of the following pathogens is most likely responsible for the most serious form of acute meningitis?

Accepted Answer

Neisseria meningitidis

Question 3

Which virulence factor of Neisseria meningitidis is primarily responsible for vascular collapse and petechiae?

Accepted Answer

Endotoxin

Question 4

Aseptic meningitis is most commonly caused by which group of viruses?

Accepted Answer

Enteroviruses

Question 5

Which of the following is a key difference between bacterial and viral meningitis?

Accepted Answer

Viral meningitis is generally milder and often resolves without treatment.

Question 6

Which of the following equations best represents the probability of transmission of Neisseria meningitidis in a college dormitory, given a carriage rate of $$p$$ and $$n$$ susceptible individuals?

Accepted Answer

$$P = p 	imes n$$

Question 7

Which form of poliomyelitis is characterized by invasion of motor neurons and results in flaccid paralysis?

Accepted Answer

Paralytic disease

Question 8

Why is the oral poliovirus vaccine (OPV) not used in the United States?

Accepted Answer

It contains an attenuated virus that can revert to a neurovirulent strain.

Question 9

Amoeba Naegleria fowleri causes primary amoebic meningoencephalitis (PAM). Which activity is most likely to lead to infection?

Accepted Answer

Swimming in warm, natural bodies of fresh water

Question 10

Which of the following best describes the pathogenesis of arbovirus-induced encephalitis?

Accepted Answer

Virus enters through an arthropod bite, replicates in tissues, and establishes infection in the brain.

Question 11

A pregnant woman is exposed to Toxoplasma gondii. Which of the following outcomes is most likely if infection occurs during the first or second trimester?

Accepted Answer

Blindness, hydrocephalus, or stillbirth in the fetus

Question 12

Which of the following is the primary reservoir for Toxoplasma gondii?

Accepted Answer

Feline family (cats)

Question 13

A patient is bitten by a wild animal and presents with symptoms of rabies. Which of the following is the most appropriate initial treatment?

Accepted Answer

Infuse the wound with human rabies immune globulin and begin a full course of rabies vaccine.

Question 14

Which neurotoxin is responsible for the symptoms of tetanus, including muscle contraction and respiratory arrest?

Accepted Answer

Tetanospasmin

Question 15

Clostridium botulinum causes botulism by releasing an exotoxin that prevents the release of which neurotransmitter?

Accepted Answer

Acetylcholine

Question 16

Which equation best represents the time before onset of botulism symptoms ($$t) as a $$function of dose size ($$d$$), given that onset ranges from 12 to 72 hours?

Accepted Answer

$$t = 12 + (72 - 12) 	imes \frac{1}{d}$$

Question 17

Which of the following is NOT a recommended prevention strategy for Toxoplasma gondii infection?

Accepted Answer

Avoiding contact with mosquitoes

Question 18

Which of the following is a common sign of meningococcemia caused by Neisseria meningitidis?

Accepted Answer

Petechiae on the trunk and appendages

Question 19

Which of the following best explains why supportive care is the main treatment for acute encephalitis caused by arboviruses?

Accepted Answer

No satisfactory antiviral treatment exists for most arboviruses.

Question 20

Which of the following scenarios is most likely to result in tetanus infection?

Accepted Answer

Accidental puncture wound with a rusty nail

Infectious Diseases Affecting the Nervous System: Microbiology Study Notes

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