In an animal model for COVID-19 that shares important features of human disease, scientists show that prior infection with the SARS-CoV-2 virus provides protection against reinfection, and treatment with convalescent serum limits virus replication in their lungs.
Syrian hamsters, commonly found as pets, have served critical roles in understanding human infectious diseases for decades. The new study, led by Yoshihiro Kawaoka and published today (June 22, 2020) in the Proceedings of the National Academy of Sciences, demonstrates they are also a useful small animal model for researchers trying to understand SARS-CoV-2 and in evaluating vaccines, treatments and drugs against the disease it causes.
«Hamsters are good models for human influenza and SARS-CoV,» says Kawaoka, professor of pathobiological sciences at the UW School of Veterinary Medicine and a virology professor at the University of Tokyo. «This is why we decided to study them with COVID-19. We wanted to see if the disease course is similar to humans in these animals from beginning to end.»
A study led by scientists at the University of Hong Kong, published in late March, also showed Syrian hamsters to be a good model for COVID-19-related research. In that study, the hamsters lost weight, became lethargic, and developed other outward signs of illness.
Kawaoka’s group extended this work further, demonstrating that both low and high doses of the virus, from patient samples collected in the U.S. and Japan, replicate well in the airways of juvenile hamsters (1 month old) and adults (7 to 8 months old). The virus can also infect both the upper and lower respiratory tracts.
The research team also showed that SARS-CoV-2 causes severe disease in the lungs of infected animals. This includes lesions and the kind of «ground glass» appearance often found in lung scans in human patients. Scans also revealed a region of gas in the cavity surrounding the hamster’s lungs, indicating severe lung damage. Researchers observed the most severe effects within eight days after infection, and improvement by 10 days.
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Materials provided by University of Wisconsin-Madison. Original written by Kelly April Tyrrell. Note: Content may be edited for style and length.