Chandipura vesiculovirus

Chandipura vesiculovirus (CHPV) is a member of the Rhabdoviridae family that is associated with an encephalitic illness, Chandipura encephalitis or Chandipura viral encephalitis, in humans. It was first identified in 1965 after isolation from the blood of two patients from Chandipura village in Maharashtra state, India and has been associated with a number of otherwise unexplained outbreaks of encephalitic illness in central India. Between June and August 2003, 329 children contrcacted the virus, and 183 died in Andhra Pradesh and Maharashtra states of India. Further sporadic cases and deaths in children were observed in Gujarat state in 2004.

In India and West Africa Chandipura vesiculovirus was isolated from sandflies and its bite probably spread the virus. The presence of the virus in Africa indicates a wide distribution although no human cases have been observed outside India.

Etymology
It was named after the village it was first identified in, Chandipura village in Maharashtra, India during an outbreak of encephalitis in 1965.

Virology
Chandipura vesiculovirus is an enveloped RNA virus with an approximate genome length of ~11 kb. Viral genome codes for five polypeptides, namely, nucleocapsid protein N, phosphoprotein P, matrix protein M, glycoprotein G and large protein L in five monocistronic mRNAs. N protein encapsidates genome RNA into a nuclease-resistant form to protect in from cellular RNAse function. L and P protein together forms viral RNA dependent RNA polymerase; where catalytic functions for RNA polymerization, capping and poly-A polymerase resides within the L protein and P acts as a transcriptional activator. Matrix protein glues the encapsidated genome RNA, also known as nucleocapsid, with the outer membrane envelope. G protein spikes out of the membrane and acts as a major antigenic determinant.

Viral life cycle is cytosolic. During transcription, viral polymerase synthesizes five discrete mRNAs and obeys to stop signals that are present at the gene boundaries. Accumulation of adequate amounts of viral proteins within infected cells through viral transcription and subsequent translation potentiate the onset of viral replicative cycle. In this phase, same L protein acts as a replicase and ignore the gene junctions to generate a polycistronic anti-genomic analogue that acts as a template for further rounds of replication to generate many more copies of the genome RNA. This progeny genome RNA upon packaging by viral proteins bud out as mature virus particles. The precise mechanism underlying the switch in polymerase function during viral replication remains unknown.

Signs and symptoms
Symptoms of Chandipura virus infection typically include fever, headache, convulsions, and unconsciousness, progressing rapidly to coma and death in severe cases. There is no specific treatment or vaccine available for Chandipura virus infection, so management focuses on supportive care and prevention measures such as mosquito control.

Past outbreaks
In 2003, 329 children in Andhra Pradesh and Maharashtra tested positive for the virus, of which 189 succumbed to the virus. In 2009, there were 52 positive cases, and 15 fatalities. In 2010, there were 50 positive cases and 16 fatalities. Between 2009 and 2011, there were 110 positive cases, and 3 fatalities.

An outbreak in Gujarat in Kheda District, Vadodara District, and Panchmahal District killed 17 people in 2010. Sandfly bites were blamed for the outbreak, as they inhabit cracks in walls or parts of homes made of sand or mud. The sporadic cases appeared in Gujarat in 2014 and 2016. In 2016, a girl from Ahmedabad succumbed to the virus. In 2019, a girl from Bhayli, Vadodara succumbed to the virus.

Recent outbreaks
In July 2024, Sabarkantha district of Gujarat in India experienced an suspected outbreak particularly in children. This suspected outbreak has raised significant public health concerns due to the rapid spread and the severity of symptoms observed in the affected individuals. So far, one death caused by the virus has been confirmed, with a suspected death toll of 14.