The World Health Organisation (WHO) has recently announced that the ongoing Chandipura virus outbreak in India is the largest in the past 20 years. Between early June and August 15, the Ministry of Health reported 245 cases of Acute Encephalitis Syndrome (AES), including 82 fatalities, resulting in a case fatality rate (CFR) of 33 per cent. A total of 43 districts in India are currently reporting AES cases. Of these, 64 are confirmed cases of the Chandipura virus (CHPV) infection.
The World Health Organisation said in its Disease Outbreak news on August 23, “CHPV is endemic in India, with previous outbreaks occurring regularly. However, the current outbreak is the largest in the past 20 years.”
CHPV, a member of the Rhabdoviridae family, is known to cause sporadic cases and outbreaks of Acute Encephalitis Syndrome (AES) in western, central, and southern India, particularly during the monsoon season.
Cases of CHPV are sporadically reported across various districts, similar to past outbreaks. Notably, Gujarat experiences a rise in CHPV outbreaks approximately every four to five years.
CHPV is transmitted by vectors like sandflies, mosquitoes, and ticks. The case fatality rate (CFR) for CHPV infection is high, ranging from 56 to 75 per cent, and there is currently no specific treatment or vaccine available.
“Survival can be increased with early access to care and intensive supportive care of patients,” the WHO said.
Surveillance efforts should be increased in high-risk areas, with a focus on individuals at risk, such as children under 15 who present with sudden fever and central nervous system symptoms, the WHO advised. It is crucial to ensure that laboratory diagnostic capabilities are in place, including the timely collection, transport, and testing of serum and cerebrospinal fluid samples for serological and virological analysis at a referral laboratory.
Since July 19, there has been a daily decline in the number of new AES cases, it added.
To date, no cases of human-to-human transmission have been reported. In 2003, Andhra Pradesh experienced a major AES outbreak with 329 suspected cases and 183 deaths. Studies suggest that this outbreak was caused by CHPV.
Although authorities are actively working to control CHPV transmission, further spread of the virus remains possible in the coming weeks. The ongoing monsoon season is creating favourable conditions for vector populations in the affected areas.
The WHO has recommended vector control and protection against bites from sandflies, mosquitoes, and ticks to prevent further spread of CHPV. Emphasizing these control and prevention measures, the WHO noted that the Union Health Ministry has deployed a National Joint Outbreak Response Team (NJORT) to support the Gujarat government in implementing public health measures and conducting a thorough epidemiological investigation into the outbreak.
Comprehensive insecticidal spraying and fumigation are being conducted to control vectors, such as sandflies, which transmit the virus. Initiatives are underway to provide information to the public and medical personnel about the virus, its symptoms and preventive measures.
