Largest Chandipura Virus Outbreak in India in Two Decades: WHO Issues Alert

The World Health Organization (WHO) recently announced that the current Chandipura virus (CHPV) outbreak in India is the largest seen in the last 20 years. From early June to August 15, the Ministry of Health reported 245 cases of Acute Encephalitis Syndrome (AES), including 82 fatalities, reflecting a case fatality rate (CFR) of 33%. As many as 43 districts across India are currently grappling with AES cases, of which 64 have been confirmed as Chandipura virus infections.

“CHPV is endemic in India, with previous outbreaks occurring regularly. However, the current outbreak is the largest in the past 20 years,” the World Health Organization (WHO) stated in its Disease Outbreak news released on August 23.

Understanding the Chandipura Virus

CHPV, a member of the Rhabdoviridae family, is known to cause sporadic cases and outbreaks of AES in various parts of India, particularly in the western, central, and southern regions. The virus tends to be more prevalent during the monsoon season, and there has been a noticeable pattern of outbreaks every four to five years, especially in Gujarat. Transmission occurs primarily through vectors such as sandflies, mosquitoes, and ticks, and the virus has a notably high case fatality rate ranging from 56% to 75%.

“Survival can be increased with early access to care and intensive supportive care of patients,” the WHO emphasized. However, there is no specific treatment or vaccine available for CHPV at present.

Surveillance and Prevention Measures Urged

The WHO has called for enhanced surveillance efforts in high-risk areas, particularly among vulnerable populations such as children under 15 years old who exhibit symptoms like acute onset of fever and central nervous system manifestations. “It is important to ensure that laboratory diagnostic capacities are available, including for timely collection, transport, and testing of serum and cerebrospinal fluid samples for serological and virological investigation at a referral laboratory,” the organization noted.

Encouragingly, a declining trend in the number of new AES cases has been observed daily since July 19. The WHO also confirmed that, to date, no cases of human-to-human transmission of the Chandipura virus have been reported.

Historical Context and Ongoing Risks

India has previously seen significant outbreaks of AES attributed to CHPV. In 2003, Andhra Pradesh experienced a major outbreak with 329 suspected cases and 183 deaths. Studies have suggested that CHPV was the cause of that outbreak. Although authorities are making efforts to contain the spread of CHPV, the WHO warned that further transmission is possible in the coming weeks due to the ongoing monsoon season, which creates favorable conditions for the vectors that transmit the virus.

Recommendations for Vector Control and Public Awareness

To prevent further spread, the WHO has recommended stringent vector control measures and protection against bites from sandflies, mosquitoes, and ticks. Highlighting ongoing control and prevention efforts, 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 detailed epidemiological investigations into the outbreak.

Efforts to control the vector population include comprehensive insecticidal spraying and fumigation aimed at eliminating sandflies and other carriers of the virus. Additionally, initiatives are underway to educate the public and healthcare providers about the virus, its symptoms, and preventive measures.

Research and Monitoring by the Gujarat Biotechnology Research Centre

The WHO also reported that the Gujarat Biotechnology Research Centre (GBRC) is actively researching to identify other viruses responsible for encephalitis and is closely monitoring the situation to prevent further outbreaks.