A few years ago, locals from Halchowk, Kathmandu, saw a common leopard wandering in broad daylight in their vicinity. Rangers from the Central Zoo, who were informed about the common leopard entering the human settlement, captured the beast.

“The leopard was seriously ailing and had also developed problems with the nervous system,” said Dr Amir Sadaula, a veterinary officer at the National Trust for Nature Conservation, Chitwan. “It did not survive even though we started treatment immediately following the rescue. Test results show the leopard was infected with canine distemper virus.”

Canine distemper is a highly contagious and serious viral disease caused by the canine distemper virus. The virus affects several body systems in dogs, including the central nervous system, spinal cord, respiratory tract, and gastrointestinal tract.

The virus does not affect humans.

Sadaula said that the deadly virus might have been passed to leopards from infected dogs. Incidents of leopards getting infected from canine distemper have increased recently, mainly in the suburban areas.

“At least four leopards, which were rescued from settlements in Kathmandu, Dolakha, Parbat and Palpa, were found infected with canine distemper virus,” said Sadaula. “We carried out lab testing on the samples of those rescued leopards in the laboratory of the National Trust for Nature Conservation, Chitwan.”

Officials say that three sub-lineages of the virus have been detected in four leopards. They attributed that sub-lineage of the virus, which killed leopards in Kathmandu and Dolakha, was similar and could have been transmitted from dogs. However, the sub-lineages in the leopards from Palpa and Parbat were different, which indicates they were transmitted from wild animals.

Along with domestic dogs, wild dogs, foxes, and other wild animals could become infected with the canine distemper virus.

Experts express grave concerns about the rising deaths of wild animals from the infection of canine distemper virus, whose fatality rate is too high (above 50 percent). Earlier, elephants were infected with tuberculosis transmitted from humans.

Leopards, searching for food, often enter human settlements to prey upon dogs. They get infected and die of the infection of the deadly virus if their prey is already infected.

Experts say that tigers, like leopards, could become infected with deadly diseases if dog infections are not prevented, which can lead to serious disasters.

“India and Indonesia have already reported canine distemper virus infection in lions and leopards,” said Sadaula. “Russia has reported infections on Amur tigers. If we fail to break the transmission chain, our tiger can also get infected.”

Experts say the only way to prevent cross-transmission is to vaccinate dogs in buffer zones.

The disease's symptoms are similar to rabies, as infected dogs exhibit nasal and eye discharge, fever, vomiting, diarrhoea, loss of appetite, seizures, or muscle tremors that can also lead to death.

Officials say the infected dogs die within two weeks.

Doctors say the world could witness a new pandemic at any time as new diseases are being passed to humans from animals.