The Kerala alert

There needs to be greater surveillance across India for the West Nile Virus

  • The death of a child in Kerala’s Malappuram district has drawn attention to the epidemiology of the little-known West Nile Virus in India.
  • Though awareness is low, the virus is endemic to several States.
  • The first documented WNV case in Kerala was in Alappuzha in 2011, with the numbers then growing.
  • However, official records do not reflect this, given the difficulty of diagnosing WNV in its acute phase.
  • More tests apart from ELISA are typically needed to confirm WNV, and while the results appear in journals, they don’t always make it to State surveillance systems.
  • Nevertheless, the alert is a welcome move which means that State health authorities will look harder for the disease.
  • Historically, wherever Indian researchers have looked for the WNV, they have found it.
  • Patient samples were sent to the Manipal Centre for Virus Research, which deployed the Plaque Reduction Neutralisation Test, more specific than ELISA.
  • If more States used such diagnostics, it would help determine just how widespread WNV is in India.
  • There is a good chance the virus is a significant cause of Acute Encephalitis Syndrome, the infamous basket of illnesses with no known aetiology that affect over 10,000 Indians each year.
  • Viruses are known to adapt for both greater virulence and more efficient transmission.
  • Urbanisation and land-use changes are bringing the virus’s zoonotic hosts, such as birds, in more frequent contact with humans.
  • Given increased mobility, viruses can hitch a ride to new regions via infected humans and vectors.
  • India’s best defence is better surveillance, which will help doctors reach patients early to prevent complications.

The Hindu

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