Which of the following is the main cause of Japanese encephalitis?

UP CHO - 10 September 2021

Microbiology

Easy

Appeared in: UP CHO - 10 September 2021

Explanation

Japanese encephalitis (JE) is caused by the Japanese encephalitis virus (JEV), a neurotropic RNA virus.
JEV belongs to the family Flaviviridae, which includes other significant human pathogens like Dengue virus, West Nile virus, and Yellow Fever virus.
It is classified as an arbovirus, which stands for arthropod-borne virus, as it is transmitted by the bite of infected mosquitoes.
The primary vector for JE is the Culex mosquito, which thrives in rice paddies and other stagnant water sources common in rural and agricultural areas of Asia.

Option A: Protozoa are single-celled eukaryotic organisms. They are responsible for diseases like malaria (Plasmodium), amoebiasis (Entamoeba histolytica), and toxoplasmosis (Toxoplasma gondii), not viral encephalitis.
Option B: Blue-green algae, or cyanobacteria, are photosynthetic bacteria. While some species can produce toxins (cyanotoxins) that are harmful to humans and animals if ingested in contaminated water, they do not cause infectious diseases like encephalitis.
Option D: Bacteria are prokaryotic microorganisms that cause a wide array of diseases. While some bacteria can cause inflammation of the brain (bacterial meningitis), Japanese encephalitis is specifically a viral infection.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Causative agent of Japanese encephalitis as background academic context rather than a clinical decision trigger.
Understanding that JE is a viral disease is critical for nurses, as it dictates that treatment is supportive rather than curative with antibiotics.
Nursing care focuses on managing fever, preventing seizures, maintaining hydration and nutrition, and monitoring for signs of increased intracranial pressure.
The most effective method of prevention is vaccination. Nurses play a key role in educating communities in endemic areas about the importance of the JE vaccine, which is part of India's Universal Immunization Program in affected districts.

How to Approach the Question

First, identify the core of the question, which is asking for the causative agent of a specific disease: Japanese encephalitis.
This is a factual recall question based on knowledge of microbiology and community health nursing.
Consider the name of the disease itself: 'Japanese encephalitis'. The term 'encephalitis' refers to inflammation of the brain, which is very commonly caused by viruses.
Evaluate the options provided: Protozoa, Blue-green algae, Virus, and Bacteria are all different classes of microorganisms.
Eliminate the incorrect options based on general knowledge. Protozoa cause diseases like malaria. Bacteria cause infections like meningitis but JE is distinct. Algae are not typical infectious agents for encephalitis.
Conclude that 'Virus' is the correct category for the pathogen causing Japanese encephalitis.

Concept Tested & Keywords

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