Controlling wildlife trade key to preventing health crises

According to a study by the New York-based Wildlife Conservation Society, controlling the movements of wildlife in markets is a cost-effective means of keeping potential deadly pandemics such as SARS and influenza from occurring. The study appears in the July edition of the journal Emerging Infectious Diseases. The cost of controlling the spread of diseases afflicting both human and animal populations has reached hundreds of billions of dollars globally.

“Few threats to global health–including poverty, security issues or climate change–are as immediately manageable as the global trade in wildlife,” said Dr. William Karesh, lead author on the study and head of WCS’ Field Veterinary Program. “By focusing our prevention efforts on wildlife markets to regulate, and wherever reasonable eliminate, this trade, we can significantly decrease the risks of disease for humans, domestic animals, wildlife and ecosystems.”

According to the study, every year millions of wild animals pass through markets on their way to regional or international destinations. Along the way, hunters, middle marketers, and consumers experience either direct or indirect contact with each animal traded. The pathogens, and even commonly benign microbes these animals carry are sometimes transmitted to other species, including humans, in the process. Domestic animals and wild scavengers in market places and villages also consume the waste and remnants of infected trade animals providing further opportunity for cross-species transmission.

Since 1980, at least 35 new infectious diseases, including HIV and Ebola Hemorraghic Fever, have emerged in humans, averaging one disease every 8 months. Besides the direct impact on people, the transmission of wildlife-borne pathogens also affects domestic animals and native species that have no resistance to exotic diseases.

Dr. Robert Cook, Vice President of Health Sciences at WCS said, “A fungal disease called chytridiomycosis, a pathogen that has been spread by the international trade in African clawed frogs, is now threatening some 30 percent of all of the amphibian species worldwide with extinction. And even parasites on animals in the trade carry animal and human pathogens, such as heartwater disease, Lyme disease, and babesiosis.”

Besides direct effects of diseases to humans and animals, the economic impacts of disease spread have totaled hundreds of billions of dollars, disrupting human livelihoods and destabilizing trade. Even in a relatively managed trading system, livestock diseases, including bovine spongiform encephalopathy, foot-and-mouth disease, avian influenza, swine flu and others have cost global economies some $80 billion, the authors of the study say. The results from the poorly regulated trade in wildlife could be even more deadly and more costly.

“The cheapest way to contain these threats would be to minimize contact between species, which would decrease the risk of pathogens jumping from one species to another,” said Karesh. “The trade flows in a network pattern, hence the major hubs in wildlife markets provide us with the best control opportunities for a fraction of the cost.”