Deadly canine distemper virus doesn’t limit itself to dogs and their kin anymore. By 2000, the disease had been reported in all families of land carnivores from racoons to hyenas to lions. Now, the disease threatens the Sumatran tiger (Panthera sumatrae), a critically endangered species.

The International Union for the Conservation of Nature estimates the viable breeding population of the Sumatran tiger numbers only 176 to 271 individuals out of a total population of 400 to 500 on the Indonesian island of Sumatra. Troubling signs of an outbreak of canine distemper virus (CDV) may threaten those surviving Sumatran tigers, reported the BBC.

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Brain damage from CDV can cause the cats to lose their natural fear of humans. The cats will then wander into villages or fail to flee from illegal hunters. In either case, the tiger usually ends up shot. A few cases of this behavior have been noted in Sumatra, but veterinarians haven’t been able to test for CDV in these wandering tigers.

“The big threats facing tigers are habitat loss and degradation and poaching, but I think the third big threat now is likely to be disease, particularly one like CDV,” John Lewis, director of Wildlife Vets International, told the BBC.

In September, Lewis will work with a team of Indonesian veterinarians to develop a system to monitor for CDV and find a laboratory where samples can be analyzed.

“Once we have got that nailed down then we start work and try to design some sort of mitigation strategy, and that won’t be easy,” said Lewis.

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Canine distemper virus kills most animals it infects. A paper in the Journal of Zoo and Wildlife Medicine noted that disease is second only to rabies in mortality rate and has been identified in all families of land carnivores: Canidae, Felidae, Hyaenidae, Mustelidae, Procyonidae, Ursidae, and Viverridae.

A study in the Journal of Veterinary Diagnostic Investigation documented CDV infections that killed 17 lions, tigers and leopards in zoos. Vets believed the cats had contracted the disease after eating infected racoons. A similar study in Clinical and Vaccine Immunology determined that CDV had killed at least 19 lions and tigers in Switzerland over the past few decades.

IMAGE: Sumatran tiger in the Frankfurt zoo (Wilfried Berns, Wikimedia Commons)