The deadly disease that has now killed more than 1,000 people in China and across the world likely jumped to humans from wildlife, most scientists agree. Exactly how or what animals involved are less than clear at this point, however.
Many of the early cases of coronavirus appeared in proximity to the Huanan Seafood Market in Wuhan, China, and investigators have found traces of the disease in samples from 22 market stalls and a garbage truck. All of these samples were taken from the western portion of the “wet” market where vendors sold live, wild animals—often poached, usually in cages stacked high on top of each other. It wouldn’t be the first time China’s demand for exotic meats and ingredients for Traditional Chinese Medicine have been credited with an infectious disease outbreak.
The science journal Nature published an article on Feb. 3 suggesting a strong link to bats, much like the related SARS outbreak in 2002. Researchers at the Wuhan Institute of Virology found a 96% genome match between the disease affecting thousands in the city and that of bat coronavirus. One study, since discredited, implicated to snakes. Other early reports suggested rats or badgers could be involved, but bats have received the bulk of the blame.
However, some researchers have pointed out that it is unlikely the disease came directly from bats, as the local populations were in the midst of their winter hibernation and probably not available for sale at the market.
An even newer report from the South China Agricultural University on Feb. 7 suggests an even stronger link to pangolins—those strange, scaled mammals one might call “Asian armadillos.” The paper claims that there is pangolin disease with a 99% genomic match to the novel coronavirus affecting Wuhan.
Now, to complicate matters even further, it is possible that pangolins are only an intermediate host, not the ultimate host, or that a bat virus combined with a pangolin virus and leapt to humans. Clearly, no one is completely sure right now.
There is significant precedent to support the idea of one animal playing middleman for severe acute respiratory syndromes between bats and people. The 2002 SARS strain is believed to have jumped from bats to palm civets—members of the mongoose family—to people. The MERS (Middle East Respiratory Syndrome) of 2012 likely used camels as an intermediary. Both times, the jump is thought to have occurred when people ate undercooked meat or drank raw milk from the animals in question. The World Health Organization states that these viruses are rendered inert at only 132°F, just in case you had some pangolin backstrap defrosting in the fridge.
In all seriousness, pangolins are truly fascinating animals. All eight species found in Asia and Africa possess thick, keratin scales for defense, rolling themselves into armor plated balls when threatened. They are related to anteaters, and pangolins’ tongues are longer than their bodies for use in extracting ants and termites from colonies.
Many international wildlife conservation organizations rank pangolins as the most trafficked mammal on the planet. Their flesh is considered a delicacy in parts of China. The scales are believed to have therapeutic qualities in Traditional Chinese Medicine, as well as in some cultures of Vietnam and Africa. The International Union for the Conservation of Nature names all eight species on their “Red List of Threatened Species,” and it’s thought that more than 100,000 individuals are trafficked to Vietnam and China every year. Many populations have already disappeared. Some animal advocates fear the recent coronavirus outbreak could cause a backlash against severely depleted Chinese pangolins. Others hope it might cause people to stop eating pangolin meat and grinding up their scales.
Unlike pangolins, bats are well-known and notorious reservoirs for disease. Ebola in Africa and Nipah virus in Asia came from bats. They are a known vector for rabies in the U.S. Scientists attribute this propensity to bats’ incredibly strong immune systems, possibly a biproduct of being the only flying mammal. During flight, bats’ heart rates run at over 1,000 beats per minute and their internal temps go well over 100 degrees, according to an article by NPR. That would kill most mammals, but bats have evolved an iron-clad immune system to handle it. As such, they have an uncanny ability to tolerate diseases. And their social structure, roosting close together in caves and tree hollows, lends itself to easy transmission. They occasionally pass these diseases on to humans and other animals by landing on fruit or food, biting, urinating, or aerosol transmission.
But look on the bright side: Many scientists believe that potential cures or therapies could derive from studying bats’ hardy immune systems. And, in the meantime, always remember to abide by smart sanitation and cooking practices when handling wild game or fish. Most of the critters we hunt, catch, and eat are rather safe, but it never hurts to know the risks.