Canine distemper threatens Siberian tigers

WASHINGTON, Nov. 7 (UPI) -- New research suggests a viral disease increasingly prevalent among domesticated dogs and the carnivores that eat them could pose a major threat to the already endangered Siberian tiger.

Recent outbreaks of the disease -- known as contracted canine distemper (CDV) -- among tigers in Russia and India have biologists worried the problem could get worse.

Scientists first realized canine distemper could infect big cats when an outbreak in 1994 resulted in the deaths of more than 1,000 Serengeti lions, roughly a third percent of the population. In 2001, at least four Siberian tigers in Russia had to be put down after they wandered into towns disoriented and dehydrated, having contracted the deadly disease. Similar outbreaks have been witnessed in India, where feral dogs are often hunted and eaten by jungle carnivores.

The lion population on the Serengeti was able to recover from the 1994 outbreak, but a new study suggests tigers are much more vulnerable, as they reach sexual maturity at a later age and would be more easily devastated by the loss of several mature community members.

The study -- carried by scientists from the Wildlife Conservation Society and published this week in the journal PLOS ONE -- showed, using mathematical models, that small tiger populations (25 or fewer individuals) exposed to the disease were roughly 55 percent more likely to die out within the next 50 years. The majority of tigers are isolated in small populations.

"In lieu of a practical means of delivering [canine distemper virus] vaccines to wild tigers, the most viable strategy to ensure their conservation is the maintenance of large connected populations within protected areas that buffer the effects of local declines," the researchers wrote in their study.

Not everyone thinks the disease is as pressing as the new study suggests.

"Thinking we can control this is totally unrealistic. We have to live with it now, and assess whether it's really serious yet," Ullas Karanth, the science director of Wildlife Conservation Society's Bangalore-based Asian chapter, told The Guardian earlier this year. "What South Africa has done, quarantining huge areas and creating disease-free spaces in the wild, is not feasible here."

Karanth says conservation efforts should be more focused on stopping poaching and the encroachment of human development and vulnerable tiger habitat.