Most infectious diseases mankind faces today originated in animals, and accordingly, international organizations aggressively monitor illnesses in livestock and wildlife that could pose a threat to humans. Researchers now warn we should be just as vigilant about emerging diseases carried by our pets.
"The benefits of pet ownership on human health, well-being and development are unquestionable, but as dogs and cats have moved from the barn, to the house, to the bedroom, the potential for disease spread to humans increases," said Michael Day, a professor of veterinary pathology at the University of Bristol in England, in a statement.
In an article in the December issue of Emerging Infectious Diseases, Day and his colleagues have called for a global initiative to monitor diseases in dogs and cats, or small companion animals, as they're known.
The team says there are a spectrum of diseases, or zoonoses, that can be carried and transmitted between humans and their pets. These furry friends can carry bacteria that cause illnesses like strep throat and pink eye in humans. Recent research even has suggested that flu infections in cats and dogs may be much more common than thought.
Posing a more serious threat is the canine rabies virus. While it's no longer a concern in most Western developed nations, the disease is estimated to kill a minimum of 55,000 people in Africa and Asia each year, though human cases are thought to be grossly underreported.
And then there's the organ-wrecking parasitic disease visceral leishmaniasis. Dogs serve as reservoir hosts for the parasite, which spreads by sand fly bites and is most common in India, Bangladesh, Nepal, Sudan, Ethiopia and Brazil. There are an estimated 500,000 new human cases of the disease each year and it can be fatal if not treated. Despite its prevalence and severity, surveillance of visceral leishmaniasis in dogs is limited and control methods vary greatly between different countries.
The scientists say most major new human diseases will have an animal origin. Dogs and cats are a potential source of such emerging pathogens, the team says, which should be a cause for concern since humans live in such close quarters with their pets. Day says there are an estimate 72 million dogs in American homes.
As part of their proposed monitoring system for veterinarians, the researchers say standards would have to be developed to identify and test for emerging diseases in pets. There would also need to be an organization in charge of a computerized database and the management and data-mining of the information it contains.
The researchers say such an effort represents a political, financial and scientific challenge. But they argue that such an initiative would help control dog and cat zoonoses and cut the risks inherent in owning pets.