Between early June and 15 August 2024, the Ministry of Health and Family Welfare of the Government of India reported 245 cases of acute encephalitis syndrome (AES) including 82 deaths (CFR 33%). Of these, 64 are confirmed cases of Chandipura virus (CHPV) infection. CHPV is endemic in India, with previous outbreaks occurring regularly, especially during the monsoon season. However, the current outbreak is the largest in the past 20 years.

The Chandipura virus (Vesiculovirus chandipura, CHPV) is a zoonotic arbovirus in the family Rhabdoviridae. The virus is endemic in several regions of India and has been detected in other countries in the South Asian subcontinent. Sporadic cases and limited outbreaks have been reported in India since 1965. The virus has also been detected in animals in some African countries (e.g. Nigeria, Senegal, Tanzania) without reported human cases.

The principal vector of CHPV in India is the sand fly Phlebotomus papatasi, which is also present in several regions of Europe. Other sand fly, mosquito and tick species are also potential vectors of the virus. A broad range of animals are suspected as vertebrate hosts of CHPV; however, little information is available on the natural ecological cycle of the virus.

The incubation period is typically short, ranging from 3 to 6 days.

CHPV infection may manifest in rapid course as a general febrile disease with meningitis and/or encephalitis (Acute Encephalitis Syndrome). Predominantly children below the age of 15 years are affected. The case fatality rate can reach 55–75%. Serological data indicate asymptomatic human infections.

There is no specific treatment or vaccine available.