Between early June to August 15, the Indian health ministry reported 245 encephalitis cases, including 64 confirmed Chandipura virus infections and 82 deaths
India is currently facing the largest outbreak of Chandipura virus (CHPV) infection in two decades, according to the World Health Organization (WHO). Between early June and August 15, there have been 245 reported cases of acute encephalitis syndrome (AES) and 82 related deaths, of which 64 were confirmed as CHPV infections.
The CHPV is an encephalitis-causing virus, which means the infection leads to an inflammation or swelling of the brain tissue. According to a 2004 article ‘Chandipura virus: an emerging human pathogen?’ published in The Lancet, the virus first was isolated in 1965, from the blood of two adults with a febrile illness in a village in Nagpur, Maharashtra. The virus is believed to be vectored by insects that are prevalent in the early monsoon period.
WHO reports the CHPV is endemic in India, with previous outbreaks occurring regularly.
“However, the current outbreak is the largest in the past 20 years,” WHO says.
A total of 43 districts in India are currently reporting AES cases. Cases are sporadically present across various districts as in previous outbreaks. Notably, there is a rise in CHPV outbreaks every four to five years in Gujarat.
CHPV is known to cause sporadic cases and outbreaks of AES in western, central and southern parts of India, especially during the monsoon season.
“It is transmitted by vectors such as sandflies, mosquitoes and ticks. The case-fatality ratio from CHPV infection is high (56-75%), and there is no specific treatment or vaccine available,” WHO reports. “Survival can be increased with early access to care and intensive supportive care of patients.”
The world health body has recommended vector control, and protection against bites of sandflies, mosquitos, and ticks, to prevent further spread of CHPV.
So far, no human-to-human transmission has been reported. In 2003, a large outbreak of AES was reported in Andhra Pradesh, with 329 suspected cases and 183 deaths. A study suggests that this was due to CHPV.
CHPV can cause high case fatality ratios, ranging from 56% to 75% as reported during previous outbreaks in India. The disease affects mostly children under 15 years and can present with a febrile illness that may progress to convulsions, coma, and in some cases, death. In children, it can lead to high mortality within 48 to 72 hours of the onset of symptoms, typically presenting with AES.
The infection has not been detected in other countries. However, according to WHO, it may be present in other countries in Asia and Africa. The sandfly vectors are abundant in South-East Asia. There is no evidence that this virus has been detected among those travelling from India to other countries.
