Kerala sounds warning on West Nile Virus before monsoon; neighbouring states on guard Premium

Kerala’s annual battle with vector-borne diseases has begun early this year, even before the South West monsoon, with West Nile Fever (WNF) being reported from several districts.

Kerala’s annual battle with vector-borne diseases has begun early this year, even before the South West monsoon, with West Nile Fever (WNF) being reported from several districts.

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The first official alert was sounded by the Health Department on May 7 and according to the IDSP report to date, the State has reported 20 suspected cases (only 10 cases confirmed so far) and two deaths are also suspected. Given that Kerala has been endemic for the WN virus for at least two decades and that 80% of cases are asymptomatic, for every officially reported case, there could be several unreported and asymptomatic cases in the community.

In symptomatic cases, patients usually have fever, headache, fatigue, myalgia, nausea and vomiting, and sometimes, swollen lymph glands. As clinical symptoms of most mosquito-borne viral diseases are similar, the possibility of WN or JE is considered only when the patient exhibits symptoms of neuroinvasive diseases like encephalitis or meningitis, collectively known as Acute Encephalitis Syndrome (AES). Thus, because of the diagnostic difficulties in identifying WNF in its acute phase, only a few cases get recorded in the State’s official surveillance mechanisms.

Only 1 in 150 cases affected by the WN virus gets a severe disease, and even fewer get encephalitis. WHO states that while serious illness can occur in people of any age, people over the age of 50 and some immunocompromised persons, like transplant patients, are at the highest risk of falling severely ill when infected with WNV.

Kerala’s Director of Health Services, K. J. Reena, said that WNF has been in the official surveillance records of Kerala every year since 2011 and that cases are being reported from almost all districts now. Districts that have reported WN cases this year include the northern districts of Thrissur, Malappuram, Kozhikode, and Palakkad.

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