The increase in the breeding of wild rats in some parts of the world raises fears of new pandemics.
- More than 800,000 potentially dangerous viruses for humans remain to be discovered.
- The genetic heritage of rats contains many viruses, some of which are unknown, which are all potential sources of infectious diseases for humans.
In a new study published January 21 in the journal Microbiomean international team of researchers has discovered a large number of viruses, some of which are unknown, in the genetic heritage of rats, which therefore constitute potential sources of infectious diseases for humans.
As a team of researchers from the World Health Organization (WHO) crisscrosses the Chinese city of Wuhan, epicenter of the SARS-CoV-2 pandemic, to find out the origin of the virus, the animal trail seems to hold the rope. The pandemic is said to have originated in pangolin, bat or a mixture of coronaviruses from both animals, shedding light on the potential dangers that animal consumption poses to our health.
Classify rodents according to their environment
Chapare hemorrhagic fever which caused the death of at least three Bolivians at the end of 2020, hepatitis E which has just infected several inhabitants of Hong Kong and the Seoul virus, a deadly hantavirus for humans, all have as their common origin the rats, immediately reminds CIRAD (the Center for International Cooperation in Agricultural Research for Development) in a press release published on January 22. In order to identify the risks and the zones of emergence in Southeast Asia, where the breeding of wild animals is in full expansion, the researchers dissected the viromes of more than 3,000 rodents of more than 30 species. Thanks to the collection of lung samples carried out from 2006 to 2018, in Thailand, Laos and Cambodia, the Academy of Chinese Medicine was able to do virus DNA sequencing work. This work is part of one of the objectives set by IPBES, an intergovernmental scientific and political platform on biodiversity and ecosystem services, in its report published on October 29, 2020 on pandemics. She states that more than 800,000 potentially dangerous viruses for humans remain to be discovered.
“We found already known viruses, in particular hantaviruses, mammarenaviruses or coronaviruses, and confirmed the role of reservoirs of certain speciescommented Serge Morand, health ecologist at CIRAD and co-author of the publication. But we have also discovered new viruses, potential sources of infectious diseases for humans..” The researchers also classified the rodents according to their preferred habitat between forest, agriculture and city. “Some rodents are specialists, i.e. they only settle in specific environments: forests, flooded agriculture, urban areas, etc. Other rodents are generalists, i.e. they grow both in the city and in the countryside. For example, the black rat, and the other species of the Rattus rattus complex, is an invasive and highly parasitized species.continues the ecologist. Classifying the animals according to their environment makes it possible to identify the areas of possible emergence of the viruses they carry.”
Wild rat farms on the rise
This study confirms the close link between the circulation of a virus and the breeding of animals which are made in this same region. The researchers thus take the example of the emergence of SARS in China in 2002, which passed from bats to humans at a time when this wild animal was being intensively farmed. “This precedent, which should have served as an example, did not prevent the recent rise of wild animal farms in Southeast Asia.”, laments CIRAD in its press release.
The researchers want to be rather worried for the future, especially since they note an increase in the breeding of wild animals, in particular certain species of rice paddy rats, in Southeast Asia. These farms, note the researchers, are often family-run and small in size and are carried out in poor sanitary conditions, without the necessary veterinary supervision. “The breeding of wild animals is increasing in Southeast Asia, and appears to be much more dangerous than the consumption of meat from huntingobserves Serge Morand. The theoretical data that we have just produced and shared with the rest of the scientific community is worth nothing if these behaviors cannot be prevented..”
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