The Canadian Food Inspection Agency (CFIA) says its scientists have confirmed that domestic chickens, turkey, and pigs pose no public health risk for transmitting the virus that causes COVID-19.
The CFIA’s research also showed these animals did not carry the virus in tissues used for meat or human consumption.
There have been no documented cases of poultry or swine becoming infected with the virus to date, but the CFIA still wanted to determine their susceptibility and the risk of transmission between animals. The research papers describing what CFIA scientists found were recently made public.
For poultry, the researchers report that they inoculated 10 four-to-six week old leghorn chickens from a CFIA flock in Nepean, Ottawa, and 10 four-to-six week old turkey pullets from a breeder in Manitoba, while maintaining control groups for both. Researchers also inoculated chicken embryos using several different methods and at different stages of development to determine if they might be susceptible prior to hatching.
After not finding any signs of susceptibility, they concluded “SARS-CoV-2 virus does not affect both turkeys and chickens in the current genetic state and does not pose any potential risk to establish in these of species of domestic poultry.”
The CFIA’s findings in pigs were slightly more complicated, as researchers explain that they administered the virus into the nostrils and mouths of 16 eight-week old American Yorkshire crossbred pigs from a high health status farm in Manitoba. The pigs were exposed to the virus at a dose 10 times higher than previous studies.
Contrary to several other studies conducted elsewhere this year, the CFIA’s researchers found the pigs were susceptible — by definition — to the SARS-CoV-2, albeit at low levels and in a lab situation designed to maximize the chance of infection. One pig out of the 16 was found to retain the live virus, while two had detectable RNA in their nasal wash, and another two pigs developed antibodies to the virus.
Most importantly, though, when it comes to possible transmission, the researchers did not detect any live viral shedding, and no RNA was found in swabs or organ samples. CFIA has concluded the virus replicated so poorly in the pigs in the lab that they are not a threat for transmission.
Livestock producers “should continue to follow normal biosecurity measures,” says the agency.
If you want to take a deeper dive into the methodology and conclusions, the research papers, which are still under review, can be found here (poultry), and here (swine).
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