Ahmedabad: There’s good news for cattle owners and veterinary doctors struggling to contain the lumpy skin disease outbreak among cattle in states like Gujarat, Rajasthan and Punjab, among others.
An indigenous vaccine against the disease, which had been in development since 2019 — using viral samples isolated from Ranchi, has successfully completed field trials and is now ready for commercial launch, scientists from the Indian Council of Agricultural Research (ICAR) told ThePrint.
In a major breakthrough, two institutes of the ICAR have developed the vaccine, called Lumpi-ProVac, which the central government now plans to commercialise at the earliest to control the outbreak that has killed thousands of cattle across several Indian states over the past month or so.
In a telephonic conversation with ThePrint, Dr Naveen Kumar — a researcher at ICAR National Research Centre on Equines in Haryana, who led the vaccine trials— explained how the vaccine was developed over the past three years.
“I had first isolated the virus in 2019 from Ranchi,” Kumar told ThePrint.
He added: “Since then, we have been working to understand the virus and develop the vaccine.”
Caused by a capripox virus, lumpy skin disease — which affects both cows and buffaloes — gets its name from the large, firm nodules that develop on the skin of the cattle as a result of the disease. Depression, conjunctivitis and excess salivation are some other symptoms found in the diseased animals.
Eventually the nodules burst, causing the animals to bleed. There is currently no cure for the viral disease, and treatment mostly targets clinical symptoms.
Currently, the vaccine being used against the disease is the goatpox vaccine, which provides some degree of protection against lumpy skin disease, too.
“But the efficacy is about 60 per cent. That is why we developed a specific vaccine for lumpy skin disease. Field trials showed that the vaccine is safe and effective,” Kumar added.
Lumpi-ProVac is a live attenuated vaccine — which means it contains weakened strains of the lumpy skin disease virus.
To weaken the viral samples, researchers conducted genetic engineering experiments, known as serial passaging.
Serial passaging is a process of growing a virus (or bacterium) in iterations to either study the properties of the mutated virus, or to develop a strain that has the desired properties.
In this case, researchers used vero cells — derived from the kidney of an African green monkey — to grow 50 new generations of the virus. Each iteration takes about a week. The entire process of arriving at the correct attenuated strain took one-and-a-half years, Kumar said.
The vaccine was then tested on mice and rabbits for safety, before field trials were conducted.
“When the vaccine appeared safe in mice and rabbits, we decided to go ahead with field trials,” he added.
The first animal trials were carried out in 15 calves in Mukteshwar (Uttarakhand) between April and June this year, Kumar said. “The trials showed us that the vaccine was also safe for animals in the field,” he said.
After this, a randomised controlled trial was carried out in dairy farms at Udaipur and Banswara (Rajasthan) in July. As many as 700 cows, buffaloes, and calves — including those that were pregnant or lactating — were administered the vaccine.
The results from these trials showed that the vaccine was not only safe, but also more effective in preventing lumpy skin disease among cattle, said Kumar.
According to Kumar, a live attenuated vaccine has better efficacy and is effective for up to one year, unlike inactivated vaccines — like the Covid vaccine Covaxin — which provide short-term protection against disease.
Lumpi-ProVac is stored in freeze dried form, and needs to be stored at 4 degrees Celsius.
ICAR will now invite expressions of interest from pharmaceuticals for the commercialisation of the vaccine, said Kumar.
(Edited by Poulomi Banerjee)