Big cats and small dogs: solving the mystery of canine distemper in wild tigers

November 23, 2020

ITHACA, N.Y. - If you think getting your cat to the veterinarian is tricky, new Cornell Wildlife Health Center research has revealed that vaccination of endangered Amur (Siberian) tigers is the only practical strategy to protect them from a dangerous disease in their natural habitat in the Russian Far East.

Canine distemper virus (CDV) causes a serious disease in domestic dogs, and also infects other carnivores, including threatened species like the Amur tiger, which numbers fewer than 550 individuals in the Russian Far East and neighbouring China. It is often assumed that domestic dogs are the primary source of CDV, but in a new study published in the Proceedings of the National Academy of Sciences, the Cornell Wildlife Health Center's Dr. Martin Gilbert and colleagues found that other local wildlife was the primary source of CDV transmission to tigers instead.

"Understanding how tigers are catching distemper is absolutely crucial to helping us design effective measures to minimize the conservation impact of the virus," said Gilbert. "Vaccinating tigers is hard to do, but our research shows that immunizing just two tigers within a small population each year can reduce the risk that CDV will cause extinction by almost seventy-five percent. At least in the Russian Far East, vaccinating local domestic dogs would not be an effective strategy to protect tigers."

The research, led by Cornell University, the Wildlife Conservation Society and the University of Glasgow, relied on several lines of evidence to build a picture of CDV epidemiology in the tigers' habitat. Using samples from domestic dogs, tigers, and other wild carnivores, they compared viral genetic sequence data and used antibodies to assess patterns of exposure in each population.

"The taiga forest where the tigers live supports a rich diversity of 17 wild carnivore species" said study co-author Dr. Nadezhda Sulikhan with the Federal Scientific Center of the East Asia Terrestrial Biodiversity of Russian Academy of Sciences. "Our findings suggest that more abundant small-bodied species like martens, badgers and raccoon dogs are the most important contributors to the CDV reservoir."

Controlling CDV in these abundant wild carnivore populations is not possible, as there are no CDV oral vaccines that could be distributed to these populations through baited food.

That left only one viable possibility -- using an injectable vaccine on the tigers themselves. To determine whether currently available CDV vaccines could protect wild tigers, the researchers showed in the laboratory that serum from tigers vaccinated in captivity was able to neutralize the strain of CDV that they had detected in Russia. They then developed a computer model to show that even a low rate of vaccination (two tigers per year) could reduce the tigers' risk of extinction significantly, at a cost of only US $30,000 per year or less if vaccines are given opportunistically when tigers are captured for routine radio collaring studies. Gilbert and his colleagues contend that vaccination can be a valuable conservation strategy. As wildlife populations become more fragmented through the effects of habitat destruction, poaching and climate change, they become increasingly vulnerable to local extinctions caused by infectious diseases like distemper.

According to study contributor Dr. Sarah Cleaveland of the University of Glasgow, "This work shows that CDV in the Amur tiger is a solvable problem -- a rare piece of good news for the tiger conservation community."

Cornell University

Related Vaccines Articles from Brightsurf:

Comprehensive safety testing of COVID-19 vaccines based on experience with prior vaccines
'The urgent need for COVID-19 vaccines must be balanced with the imperative of ensuring safety and public confidence in vaccines by following the established clinical safety testing protocols throughout vaccine development, including both pre- and post-deployment,' write David M.

Safety of HPV vaccines in males
A new analysis published in the British Journal of Clinical Pharmacology shows that HPV vaccines are safe and well tolerated in the male population, and the side effects that may occur after immunization are similar in both sexes.

Model could improve design of vaccines, immunotherapies
Researchers have discovered a general property for understanding how immune cell receptors sense and respond to microbial signals, which could lead to more effective vaccines for both existing and novel viruses.

Better vaccines are in our blood
Red blood cells don't just shuttle oxygen from our lungs to our organs: they also help the body fight off infections by capturing pathogens in the blood and presenting them to immune cells in the spleen.

Challenges in evaluating SARS-CoV-2 vaccines
With more than 140 SARS-CoV-2 vaccines in development, the race is on for a successful candidate to help prevent COVID-19.

Designing vaccines from artificial proteins
EPFL scientists have developed a new computational approach to create artificial proteins, which showed promising results in vivo as functional vaccines.

Misinformation on vaccines readily available online
Parents researching childhood vaccinations online are likely to encounter significant levels of negative information, researchers at the University of Otago, Wellington, have found.

Battle with the cancer: New avenues from childhood vaccines
A new research from the University of Helsinki showed for the first time how the pre-immunization acquired through common childhood vaccines can be used to enhance therapeutic cancer treatment.

Personalized cancer vaccines
The only therapeutic cancer vaccine available on the market has so far showed very limited efficacy in clinical trials.

Doubts raised about effectiveness of HPV vaccines
A new analysis of the clinical trials of HPV vaccines to prevent cervical cancer raises doubts about the vaccines' effectiveness.

Read More: Vaccines News and Vaccines Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to