Study in China uncovers new viruses in fur animals

A study involving over 450 fur-bearing animals in China has uncovered a variety of previously unknown viruses, some of which have shown the ability to cross species, raising concerns about their potential to infect humans. 

The research published in the latest issue of Nature, identified raccoon dogs and minks as the primary carriers of these high-risk viruses. One of the most concerning discoveries was a mink virus that bears close resemblance to those typically found in bats. Out of the 28 animal species examined, most were raised for their fur, meat, or medicinal purposes, and all had died from disease.

The study’s authors emphasized the critical role fur farming plays in viral zoonoses, with several of these viruses having already made the jump to humans. For this study, initiated in 2021, researchers collected tissue samples from 461 diseased animals across China, identifying 125 different viruses. Of these, 36 were previously unknown, and 39 posed a significant risk of crossing the species barrier, potentially leading to human infection.

Animals play a significant role in the transmission of viruses to humans, a phenomenon known as zoonosis. Zoonotic diseases can emerge when viruses from animals cross species barriers and infect humans, often through direct contact, consumption of animal products, or indirect contact via vectors like mosquitoes. As human activities increasingly encroach on natural habitats, the risk of zoonotic transmission grows, heightening concerns about future outbreaks.

The researchers warned that the close quarters and intensive breeding environments of fur farms could act as incubators for virus spillover events. Of particular concern was a Mers-like coronavirus found in mink, closely related to bat coronaviruses, which have a history of recombining into new strains.

Other viruses identified included a newly discovered “rabbit coronavirus” and several other coronaviruses found in high numbers in the dead animals’ organs. Cross-species transmission has been the root cause of several pandemics in human history, underscoring the need for vigilance.

This study also follows a pattern of zoonotic transmission risks associated with fur farming, as seen in previous outbreaks such as the 2020 mass culling of minks in Denmark due to concerns that the animals were spreading a mutated strain of the coronavirus. Such incidents further highlight the need to monitor farmed animals to prevent the next potential pandemic.

The authors of the study also called for more extensive research on the viruses circulating in fur-farmed animals to better understand their potential for zoonotic transmission, as fur-bearing animals like foxes, civets, and mink have long been suspected of harbouring viruses that can be transmitted to humans.

Some well-known examples of animal-borne viruses is the Ebola virus, which is believed to originate from fruit bats. The virus spreads through contact with infected animals, such as monkeys or bats, and has caused several severe outbreaks in Africa, including the 2014–2016 West African Ebola epidemic, which resulted in over 10 000 deaths. The SARS-CoV-2 virus, which caused the COVID-19 pandemic, also exemplifies the dangers of zoonotic transmission.

The virus is thought to have originated in bats and may have spread to humans through an intermediary species, possibly pangolins, in a wet market in Wuhan, China. COVID-19 has had profound global effects, killing millions and disrupting economies worldwide. Other zoonotic diseases like rabies, which spreads from animals like dogs, bats, and raccoons, and avian influenza (bird flu), transmitted from birds to humans, highlight the ongoing risks associated with human-animal interactions.

The researcher’s reiterated that the study highlights the danger of viruses moving from wild species like bats into farmed animals, which then come into close contact with humans. This process, Holmes stressed, is exactly the kind of interaction that can lead to pandemic-causing viruses such as Sars-CoV-2.

The authors also noted limitations in the study, such as the small sample sizes and the focus on deceased animals, which may not fully reflect the viruses present in healthy fur-farmed animals. 

The transmission of viruses from animals to humans remains a critical public health issue. The research presented an urgent reminder of the risks posed by virus transmission from animals to humans, particularly within the fur farming industry, providing a need for proactive measures to prevent future outbreaks.

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