Speaking of wet markets, a new research paper offers the results of an exhaustive review of the animals sold in the wet markets in Wuhan before the outbreak of COVID-19. Perhaps most surprisingly, the review of more than 36,000 animals of 38 species in 17 wet market shops concludes that pangolins and bats were not sold in the wet markets of the city. But the study cannot rule out that some other species of animal sold in the city’s wet markets was the source of the virus.
From May 2017 to November 2019 — long before anyone had heard of COVID-19 — Xaio Xaio, of the Lab Animal Research Center at the Hubei University of Chinese Medicine in Wuhan, conducted monthly surveys of all 17 wet market shops in the city selling live wild animals for food and pets. Xaio was attempting to trace a tick-borne virus, SFTS — severe fever with thrombocytopenia syndrome. (The paper calls Xaio’s detailed census of the animals sold in the markets “serendipitous.”)
The investigation of the animals sold sounds pretty thorough:
X.X. was granted unique and complete access to trading practices. On each visit, vendors were asked what species they had sold over the preceding month and in what numbers, along with the prices and origin of these goods (wild caught or captive bred/ farmed). Additionally, to substantiate interview data, the number of individuals available for sale at the time of each visit was noted, and animals were checked for gunshot wounds (from homemade firearms—gun ownership is strictly regulated in China) or leg-hold (snap) trap injuries, indicative of wild capture.
Across all 17 shops, vendors reported total sales of 36,295 individuals, belonging to 38 terrestrial wild animal species, averaging 1170.81 individuals per month Including species sold by weight inflated this total to 47,381 individuals. Notably, no pangolin or bat species were among these animals for sale.
But this information doesn’t completely slam the door on the wet market theory, because bats and pangolins are not the only species that could have carried the virus.
Almost all animals were sold alive, caged, stacked and in poor condition. Most stores offered butchering services, done on site, with considerable implications for food hygiene and animal welfare. Approximately 30 percent of individuals from 6 mammal species inspected had suffered wounds from gunshots or traps, implying illegal wild harvesting. Thirteen of these 17 stores clearly posted the necessary permits from Wuhan Forestry Bureau allowing them to sell legitimate wild animal species (e.g., Siamese Crocodile (Crocodylus siamensis), Indian Peafowl (Pavo cristatus), Common Pheasant (Phasianus colchicus) and Amur hedgehog (Erinaceus amurensis)) for food; four shops had no such permit. Species names were given in Chinese only, with no clear taxonomic binomial designation. None of the 17 shops posted an origin certificate or quarantine certificate, so all wildlife trade was fundamentally illegal. Notably, vendors freely disclosed a variety of protected species on sale illegally in their shops, therefore they would not benefit from specifically concealing pangolin trade or the trade in any particular species, and so we are confident this list is complete.
So which other animals have been found with SARS-CoV-2? This March, Nature listed “cats and dogs, to pumas, gorillas and snow leopards in zoos, and farmed mink” as animals that have been infected with SARS-CoV-2 after encountering an infected human being. Another study noted, “sporadic SARS-CoV-2 virus cases have been recorded in kept ferrets in Slovenia and in Spain.”
The new study reports that on average, each month the city’s wet markets collectively sold 38 racoon dogs, and ten minks. The original SARS virus was found in civet cat cages, and the markets sold about eleven masked palm civets per month. And if SARS-CoV-2 is contagious in a lot of varieties of small mammals… the markets sold on average of 332 amur hedgehogs, 168 Chinese hares, 43 Chinese bamboo rats, 30 red foxes, and a wide variety of others each month. That’s a long list of suspects.