Virology: Japanese encephalitis: practice question

A Microbiology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Microbiology · Virology: Japanese encephalitis

Sample item

An outbreak of encephalitis in children occurs in a rice-growing district with extensive pig rearing after the monsoon. Which vector and amplifying host explain the transmission?

AAnopheles mosquito, with monkeys as the reservoirBAedes aegypti, with humans as the main reservoirCIxodid tick, with rodents as the reservoirDCulex mosquito, with pigs and wading birds as amplifying hosts

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

D. Culex mosquito, with pigs and wading birds as amplifying hosts

Japanese encephalitis virus is a flavivirus transmitted by Culex tritaeniorhynchus, which breeds in flooded rice fields. Pigs and ardeid birds develop high viraemia and amplify the virus, whereas humans are dead-end hosts. Vaccination of children in endemic districts is the main control measure, and diagnosis is by IgM capture ELISA in CSF or serum.

Option by option

A. Anopheles mosquito, with monkeys as the reservoir
Anopheles transmits malaria and is not the vector of this virus.
B. Aedes aegypti, with humans as the main reservoir
Aedes aegypti transmits dengue, and humans are not the reservoir for Japanese encephalitis.
C. Ixodid tick, with rodents as the reservoir
Ticks are not the vector of Japanese encephalitis virus.
D. Culex mosquito, with pigs and wading birds as amplifying hosts (correct)
Correct. Culex mosquitoes from rice fields carry virus amplified in pigs and wading birds.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Microbiology question

What is the answer to this Microbiology question?

The best answer is D, Culex mosquito, with pigs and wading birds as amplifying hosts. Japanese encephalitis virus is a flavivirus transmitted by Culex tritaeniorhynchus, which breeds in flooded rice fields.

Why is "Anopheles mosquito, with monkeys as the reservoir" not the answer?

Anopheles transmits malaria and is not the vector of this virus.

Why is "Aedes aegypti, with humans as the main reservoir" not the answer?

Aedes aegypti transmits dengue, and humans are not the reservoir for Japanese encephalitis.

Why is "Ixodid tick, with rodents as the reservoir" not the answer?

Ticks are not the vector of Japanese encephalitis virus.

What concept does this question test?

It tests Virology: Japanese encephalitis in Microbiology. Pigs and ardeid birds develop high viraemia and amplify the virus, whereas humans are dead-end hosts. Vaccination of children in endemic districts is the main control measure, and diagnosis is by IgM capture ELISA in CSF or serum.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Virology: Japanese encephalitis?

Make a one-line identity card for each organism: shape and stain, defining test, toxin, disease and drug. Then use the flashcards and the other Microbiology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.