The Indian Institute of Science (IISc) has now tracked the virus behind India’s lumpy skin cattle crisis. The research insights pave the way for improved diagnostics and vaccines in veterinary healthcare.
In May 2022, cattle across India succumbed to a devastating outbreak of lumpy skin disease where, about 1,00,000 cows lost their lives. The outbreak severely affected India’s agricultural sector. It was a calamity and a national emergency,” said Utpal Tatu, Professor, Department of Biochemistry, IISc.
Prof. Tatu is part of a multi-institutional team probing the cause of the outbreak. The research study is published in BMC Genomics and provides critical insights into the evolution of the virus strains fuelling it.
The viral infection caused by the lumpy skin disease virus (LSDV), is transmitted by insects like flies and mosquitoes. It causes fever and skin nodules, and can be fatal for cattle. LSDV was first found in Zambia in 1931 and remained confined to the Sub-African region until 1989, after which it started spreading to the Middle East, Russia and other southeast European nations, before spreading to South Asia. There have been two major outbreaks in India. The first in 2019 and a severe outbreak in 2022, infecting over two million cows, he said.
The team collected skin nodules, blood and nasal swabs from infected cattle from Gujarat, Maharashtra, Rajasthan and Karnataka, in collaboration with veterinary institutes. Advanced whole-genome sequencing was done where DNA was extracted from 22 samples.
“The lack of an established LSDV genome sequencing was a challenge. We had to adapt techniques from Covid-19 research. Since data was limited, we compiled all available global LSDV genome sequences to make our analysis robust,” said Ankeet Kumar, PhD student, IISc and co-lead author.
Genomic analysis revealed two distinct LSDV variants circulating in India. One was with a low number of genetic variations. The other was with a high number of genetic variations. The sequence with fewer variations was genetically similar to the 2019 Ranchi and 2020 Hyderabad strains that were sequenced previously. The samples with high variations, however, turned out to be similar to LSDV strains from an outbreak in Russia in 2015.
Viruses that have DNA as the genetic material like LSDV are generally more stable than RNA viruses. Therefore, finding so many genetic variations could explain the severity of the disease, stated Kumar.
The team spotted genetic variations of over 1,800. There were a large number of genetic variations in viral genes critical for binding to host cells, evading immune response, and replicating efficiently. It as this that increased the virus’s ability to cause disease. “Cattle developed severe symptoms in regions where highly diverse strains, we spotted suggesting that genetic variations could elevate the virulence,” he said.
Such insights can pave the way for improved diagnostics, vaccines and interventions to combat emerging infectious diseases. In fact, Prof. Tatu’s research group has conducted similar studies on Covid-19 during the pandemic, and more recently on the rabies virus.
“The genomic data will prove invaluable for vaccine development by revealing molecular hotspots and genetic variations to target. This is a first for characterising the genomic landscape of LSDV on a national scale. This research represents an example of One Health approach wherein molecular biologists, computational experts and veterinary doctors address issues of national relevance. Collaboration between veterinary experts and multiple scientific institutions is critical to trace virus variants across India,” said Prof Tatu.
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