From UPSC perspective, the following things are important :
Prelims level : West Nile Virus
Mains level : Vector borne diseases
The Kerala health department is on alert after the death occurred due to the West Nile Virus.
West Nile Virus
- The West Nile Virus is a mosquito-borne, single-stranded RNA virus.
- According to the WHO, it is a member of the flavivirus genus and belongs to the Japanese Encephalitis antigenic complex of the family Flaviviridae.
How does it spread?
- Culex species of mosquitoes act as the principal vectors for transmission.
- It is transmitted by infected mosquitoes between and among humans and animals, including birds, which are the reservoir host of the virus.
- 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.
- It is not known to spread by contact with infected humans or animals.
Symptoms of WNV infection
- The disease is asymptomatic in 80% of the infected people.
- The rest develop what is called the West Nile fever or severe West Nile disease.
- In these 20% cases, the symptoms include fever, headache, fatigue, body aches, nausea, rash, and swollen glands.
- Severe infection can lead to encephalitis, meningitis, paralysis, and even death.
- It is estimated that approximately 1 in 150 persons infected with the West Nile Virus will develop a more severe form of the disease.
- Recovery from severe illness might take several weeks or months.
- It usually turns fatal in persons with co-morbidities and immuno-compromised persons (such as transplant patients).