The lumpy skin disease (LSD) virus that has killed at least 50,000 cattle in India this year may be structurally different from the version of the virus prevalent in India in 2019, raising questions whether the new vaccine being development to protect livestock can be protective enough. .
Scientists from the Scientific and Industrial Research Council of the Institute of Genomics and Integrative Biology (CSIR-IGIB) and the State Disease Diagnostic Center in Jaipur analyzed five animals showing symptoms of the disease and compared the genomes of the virus extracted from them. Six genomes (there were multiple genomes from a single animal) showed it had “little similarity to global genomes” compared to genetic sequences from previous outbreaks of the disease.
The analysis of the genomes revealed 177 unique variants, none of which were found in four genome sequences from India belonging to the 2019 outbreak of the disease filed in GenBank, a popular database.
“Virus sequence analysis suggests that the 2022 outbreak genomes harbor a large number of genetic variations from the reference genome and form a distinct lineage,” authors Lenin Bhatt, Rahul C. Bhoyar, Bani Jolly, Ravi Israni, Harie Vignesh, Vinod Scaria, Sridhar Sivasubbu say in their post. The study appears on the Bioarxiv preprint server and has not yet been peer reviewed.
This is important because Lumpi-ProVacInd, a vaccine developed by the Indian Veterinary Research Institute and the National Equine Research Center of the Indian Council of Agricultural Research (ICAR) is based on LSD virus samples from cattle from Ranchi affected by the 2019 outbreak. However, experimental trials conducted on animals affected by the ongoing 2022 outbreak with the vaccine have shown encouraging results, ICAR and the agriculture ministry said.
The vaccine is a live attenuated or weakened version of the virus which, when injected into animals, should boost the immune system and protect against likely infection. Currently, the only vaccines available against the disease are the goat pox and sheep pox vaccines, which are related to the LSD virus.
“That’s the million dollar question what the implications of this genome sequencing mean for the vaccine,” said Sridhar Sivasubbu of CSIR-IGIB and one of the scientists associated with the genome sequencing study. .
This specific study, he said, shed no light as there were too few animals tested and only a larger sample of viral genomes spanning several states could respond if the variants identified and analyzed in Rajasthan in part of the study were prevalent in India.
Another concern raised by the IGIB study is that one of the animals appeared to have two different variants of the LSD virus when the virus was extracted from its nose as well as from the skin, suggesting that the virus appeared to be able to evolve in a single host. This again speaks to the increased infectivity of the LSD virus in 2022 compared to 2019.
Lumpy skin disease is a contagious viral disease that is spread in cattle by mosquitoes, flies, lice and wasps through direct contact, and through contaminated food and water. The disease causes fever and nodules on the skin, and it can be fatal.
Symptoms include skin lumps about two to five centimeters in size, high fever, reduced milk supply, loss of appetite, and watery eyes. The Center recently said that around 57,000 cattle have died so far due to the disease which has spread to Gujarat, Rajasthan, Punjab, Haryana, Uttar Pradesh and India. Andhra Pradesh.
The disease has raised concerns about its impact on the dairy industry. India is the largest milk producer in the world with around 210 million tons per year.