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

What is West Nile Virus(WNV) ?

  1. The West Nile Virus is a mosquito-borne, single-stranded RNA virus. 
  •  RNA virus is the virus that has single-stranded as well double-stranded RNA as its genetic material. 
  • Noticeable sickness because of RNA virus is (severe acute respiratory syndrome) SARS, influenza, common cold, Hepatitis B and C.
  1. It is a flavivirus associated with the viruses that cause St. Louis encephalitis, Japanese encephalitis, and yellow fever. 
  •  The Flaviviridae are a cluster of positive, single-stranded, enveloped RNA viruses. Members of this cluster belong to a single genus, Flavivirus. 
  • They are observed in arthropods, (mainely ticks and mosquitoes), and can sometimes infect people. 


  1. Culex species of mosquitoes act as the main vectors for transmission. 
  2. It is transmitted by infected mosquitoes among and between people and animals, together with birds, which might be the reservoir host of the virus. 
  •  Mosquitoes emerge as infected once they feed on infected birds, which circulate the virus in their blood for some days. 
  • The virus subsequently gets into the mosquito’s salivary glands. 
  • When mosquitoes bite, the virus can be injected into human beings and animals, in which it could multiply and probably cause illness.
  1. It also can spread through blood transfusion, from an infected mom to her child, or through exposure to the virus in laboratories. 
  2. It isn't always known to spread through contact with infected people or animals. 


  1. The disease is asymptomatic in 80% of the infected people. 
  2. The rest develop what's known as the West Nile fever or severe West Nile disease. For them, the signs and symptoms include: 
  • fever, headache, fatigue, body aches, nausea, rash, and swollen glands. 
  • It usually turns deadly in people with comorbidities and immuno-compromised people (like in transplant patients). 
  1. Severe contamination can result in neuroinvasive disease such as West Nile encephalitis or meningitis or West Nile poliomyelitis or acute flaccid paralysis.
  • Neuroinvasive diseases are capable of infecting the nervous system and particularly the central nervous system. 
  1. WNV-associated Guillain-Barré syndrome and radiculopathy have also been reported. 
  • Guillain-Barre syndrome is an unprecedented ailment in which the immune system of one’s body attacks its own nerves. 
  • Radiculopathy is a mechanical compression of a nerve root usually on the exit foramen or lateral recess

Cases in India :

  • In India, antibodies against WNV were first detected in humans in Mumbai in 1952 and virus activity has since been reported in southern, central, and western India.
  •  WNV has been remoted in India: 
  1. from Culex vishnui mosquitoes in Andhra Pradesh and Tamil Nadu, 
  2. from Culex quinquefasciatus mosquitoes in Maharashtra, and 
  3. from people in Karnataka. 

Precaution against WNV:

  1. Since WNV outbreaks in animals precede human cases, the status quo of an active animal health surveillance system is beneficial in offering early warning. 
  2. The peak for WNV infections usually coincides with the duration when mosquito vectors are most active and the ambient temperature is adequately high for virus multiplication. 
  3. Hence, health agencies and authorities globally advice for personal protective measures to reduce the risk of mosquito bites including 
  • the use of mosquito repellents, and 
  • for public health departments to ensure larval source reduction particularly at breeding and resting sites for the mosquito vectors. Treatment No WNV-specific prophylaxis, remedy or vaccine is available. So, most effective supportive treatments are given to neuroinvasive WNV patients.


  • The best way to avoid WNV is to prevent mosquito bites as well as to keep the surrounding in a neat and mosquito free state
  • There are no specific vaccines or treatments for human WNV disease  in this case scenario , there is a need for collective precautionary measures to be taken by the institutions as well as the individuals to prevent the spread.