West Nile Virus

In News: The Kerala health department is on alert after the death of a 47-year-old from Thrissur due to the West Nile Virus.

• Earlier in 2019, a six-year-old boy in Malappuram district had died of the same infection.
• The virus was first reported in the state in Alappuzha in 2006 and then in Ernakulam in 2011.

West Nile Virus

• The West Nile Virus is a mosquito-borne, single-stranded RNA virus
• It is a member of the flavivirus genus and belongs to the Japanese encephalitis antigenic complex of the family Flaviviridae.
• WNV is commonly found in Africa, Europe, the Middle East, North America and West Asia

Detection of WNV:

• WNV was first isolated in a woman in the West Nile district of Uganda in 1937.
• It was identified in birds in the Nile delta region in 1953. Before 1997, WNV was not considered pathogenic for birds.
• WNV outbreak sites are found along major bird migratory routes.
• Human infections attributable to WNV have been reported in many countries for over 50 years.

Transmission:

• WNV is an infectious disease spread by infected mosquitoes.
• It spreads from birds to humans with the bite of an infected Culex mosquito. It can lead to a fatal neurological disease in humans.
• Mosquitoes become infected when they feed on infected birds, which circulate the virus in their blood for a few days. The virus eventually gets into the mosquito’s salivary glands. During later blood meals (when mosquitoes bite), the virus may be injected into humans and animals, where it can multiply and possibly cause illness
• WNV can also spread through blood transfusion, from an infected mother to her child, or through exposure to the virus in laboratories.
• To date, no human-to-human transmission of WNV through casual contact has been documented

Symptoms:

• The disease is asymptomatic in 80% of the infected people
• The symptoms include a fever, headache, body aches, skin rash, and swollen lymph glands. They can last a few days to several weeks, and usually go away on their own.
• If West Nile virus enters the brain, it can be life-threatening.
• It may cause inflammation of the brain, called encephalitis, or inflammation of the tissue that surrounds the brain and spinal cord, called meningitis.

Treatment:

• There are no specific vaccines or treatments for human WNV disease.
• The best way to avoid WNV is to prevent mosquito bites.

Previous Year Questions (PYQs)

Q.1) Consider the following statements:

1. In tropical regions, Zika virus disease is transmitted by ‘the same mosquito that transmits dengue.
2. Sexual transmission of Zika virus disease is possible.

Which of the statements given above is/are correct?

1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2

Source: Indian Express