Tigers at an exotic cat refuge in Texas have been stricken with canine distemper virus (CDV), a contagious and often deadly disease for which there is no cure in felines.
In-Sync Exotics Wildlife Rescue and Education Center in Wylie, Texas, has reported a number of their big cats dying from CDV and more than a dozen big cats at the refuge have contracted it.
"I can be looking at them one day and be thinking they're OK, and the next day they have a seizure and die," the center's founder, Vicky Keahey, told The Associated Press.
Reports of tigers and lions contracting CDV have been tricking in for a number of years. It has been know for at least 30 years that CDV can affect big cats. About 1,000 lions were killed by CDV in Tanzania's Serengeti National Park in 1994, the AP reported.
A recent study of Amur (also known as Siberian) tigers suggested that at least one percent of the Amur population has been killed by the virus since 2009.
Tigers and lions infected with CDV appear sluggish and disoriented. CDV targets the respiratory and digestive systems of animals, but the deadliest aspect of the disease targets the central nervous system -- causing the animals to be come disoriented and to not exhibit fear in situations where they normally would. One online video shows an infected tiger wandering openly along a crowded road in Russia.
In-Sync Exotics Wildlife Rescue and Education Center reports that felines in the Panthera genus, which includes lions, tigers, jaguars and leopards, can become infected by CDV, but other big cats such as cheetahs, bobcats, lynx and servals cannot. The virus can be contracted by ferrets, racoons and, of course, dogs as well.
"We believe that wild raccoons brought the virus onto our property. Animal control has been trapping and testing many raccoons in North Texas, and the majority of them are testing positive for CDV," the refuge wrote on its website. "We are near a lake, and our property is heavily treed, so we do have a large number of raccoons in the immediate area."
A disease called feline distemper virus also exists and there is a vaccination for it, which the big cat refuge says it administers to its felines. But there is no approved vaccine for canine distemper in big cats, the refuge stated.
"They cannot receive the dog version of the vaccine, as it is a live virus vaccine and has been known to cause extremely serious problems in big cats. We have administered the ferret version of the vaccine, which isn't thought to cause serious problems, but it also isn't known whether or not it actually provides them any protection. 24 of our cats received this vaccine, including the 4 that we lost," the refuge wrote online.
The outbreak at the big cat refuge is being studied by scientists at Tufts University and Boston University, the AP reported.
"There's definitely something different about what happens when this virus gets into the system of a big cat as opposed to other species but we don't really know what that is," said Claire Sharp, assistant professor of clinical sciences at Tufts University's Cummings School of Veterinary Medicine.