What causes the amplification of Japanese Encephalitis disease (Amplifier of JE)?

MP CHO-2020

Applied Microbiology & Infection control

Easy

Appeared in: MP CHO-2020

Explanation

Pigs are the primary amplifying hosts for the Japanese Encephalitis (JE) virus.
An amplifying host is an animal in which the virus multiplies to very high levels (high-titer viremia), making it a potent source of infection for vectors.
Infected pigs often show no signs of illness but have enough virus in their blood to easily infect mosquitoes that bite them.
This role as an amplifier is central to the spread of JE from its natural reservoir (birds) to humans via the mosquito vector.

Option A: Cows can be infected with the JE virus, but they do not develop a high enough level of virus in their blood (viremia) to efficiently transmit it to mosquitoes. Therefore, they are not considered amplifying hosts.
Option B: While some primates can be infected by arboviruses, monkeys are not recognized as the primary amplifying hosts in the established transmission cycle of Japanese Encephalitis.
Option D: Cats are not known to play any significant role in the natural transmission cycle of the Japanese Encephalitis virus.

Clinical Relevance

Nursing practice connection: Knowing Transmission cycle and amplifying host of Japanese Encephalitis (JE) helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Understanding that pigs are amplifying hosts is vital for public health strategies, such as advising communities to locate pig farms away from residential areas to reduce human-vector contact.
Nurses play a key role in educating the public about JE prevention, including mosquito control measures (e.g., eliminating stagnant water, using bed nets) and the importance of the JE vaccine in endemic areas.
What if? If a patient presents with acute encephalitis symptoms in a rural, rice-farming area with many pigsties, the nurse should have a high index of suspicion for JE and ensure prompt diagnostic testing and reporting to public health authorities.

How to Approach the Question

First, identify the keyword 'amplifier' in the question. In epidemiology, an amplifying host is a species that allows a pathogen to replicate to high levels, increasing the number of infectious agents available for transmission.
Next, recall the transmission cycle of Japanese Encephalitis, a well-known mosquito-borne viral disease common in rural and agricultural areas of Asia.
Evaluate the options based on their known roles in zoonotic diseases. Consider the typical environment for JE transmission (proximity to rice paddies and domestic animals).
Eliminate options that are not central to the JE cycle. While other animals might be bitten, the key is which one 'amplifies' the virus to high levels.
Select the pig, which is the classic and most significant amplifying host for the JE virus, bridging the gap between the natural reservoir (birds) and human cases.

Concept Tested & Keywords

Concept Tested: Transmission cycle and amplifying host of Japanese Encephalitis (JE).
Stem keywords: Japanese Encephalitis, JE, amplification, Amplifier
Lead-in keywords: What causes

QFRpqApGtTqYJwi5j49job

E6 Parks TextBook of Preventive & Social Medicine part 1 — Subpart B (pp 202-403 of 604) pp. 148-150, 149-151