Genome mapping of Chandipura virus: findings

Contact Counsellor

Last Updated06/09/2024

The Chandipura virus has not evolved much since 2003, when India saw its deadliest ever outbreak.

The Gujarat Biotechnology Research Centre (GBRC) in Gandhinagar has successfully mapped the genome of the Chandipura Vesiculovirus (CHPV). This virus was responsible for a significant number of encephalitis cases during the July-August outbreak in Gujarat.
The genome mapping will provide critical insights into understanding the virus and developing preventive measures.

Chandipura is a viral infection linked to Acute Encephalitis Syndrome (AES), causing symptoms such as fever, headache, and brain swelling. In severe cases, it can lead to convulsions, coma, and death within a few days.
The disease predominantly affects children under 15 years of age and can be transmitted by sandflies, ticks, and Aedes aegypti mosquitoes.

During the current outbreak, many children who contracted the virus experienced high fever, rashes from sandfly bites, convulsions, brain swelling, and multi-organ failure within 72 hours.
Without specific treatment, the virus can have a mortality rate between 56% to 75%, as observed during the 2003 outbreak in Andhra Pradesh and Gujarat. The case fatality rate in the recent outbreak stood at about 45%.

Genome mapping involves identifying the location of genes on a virus's chromosomes. This information is essential to track the origin, mutations, and changes in a virus's transmissibility or severity. Sequencing the virus's genome allows researchers to monitor outbreaks and develop diagnostic tests, vaccines, and therapeutics.

Genome mapping was pivotal in managing the Covid-19 pandemic, as the early release of the virus's genetic sequence helped in the development of tests and vaccines. Similarly, genome mapping of the Chandipura virus will help in formulating preventive strategies and tools.

The genome mapping revealed that the Chandipura virus has not undergone significant changes since the 2003-04 outbreak. There were only four notable mutations in the glycoprotein gene, a critical part of the virus responsible for binding to human cells.
The virus has remained similar to the 2012 strain, with just a single amino acid substitution. This indicates the virus has not been under "selection pressure" to escape immunity, possibly due to the lack of a vaccine for Chandipura.

Researchers found that the viral load in affected patients was low, as indicated by a high Cycle Threshold (Ct) value in RT-PCR tests. Despite the low viral load, the virus was still capable of causing severe symptoms, making it deadly even at low levels.

The genome sequence of the virus closely matched strains from previous outbreaks in India, confirming that the virus was not imported from abroad. The current outbreak was caused by a variant of the virus that had been circulating in India since 2003.