Kerala is on alert after a 47-year-old man died on Sunday due to West Nile fever in Thrissur district. Health officials said this was the state’s first death caused by the mosquito-borne disease in three years.
West Nile virus is an enveloped, single-stranded RNA virus and member of the Flaviviridae family. The Kerala health department said West Nile fever is spread by the Culex species of mosquitoes. According to the World Health Organization, it can cause a fatal neurological disease in humans but most infected will not show any symptoms. It is mainly transmitted through the bites of infected mosquitoes.
The Centers for Disease Control (CDC) states that WNV is the leading cause of mosquito-borne disease in the continental United States. The WHO says birds are natural hosts of WNV, while the virus is maintained in a cycle involving transmission between birds and mosquitoes. Humans, horses and other mammals can be infected.
While the most common cause of infection in humans is due to the bite of an infected mosquito, these vectors are likely to carry the disease if they feed on infected birds. The WHO says WNV can also be transmitted on contact with other infected animals, their blood, or other tissues.