Abstract
Potentially relevant to the recent appearance of COVID-19 in China is the fact that there is a belt of selenium deficiency running from northeast to southwest in the country and, indeed, China has populations that have both the lowest and the highest selenium status in the world. A set of interesting studies published by the Beck laboratory in the 1990s showed that host selenium deficiency increased the virulence of RNA viruses such as coxsackievirus B3 and influenza A. Passage through a selenium-deficient animal that was unable to produce sufficient antioxidant selenoproteins for its own protection resulted in the virus mutating to a virulent form that caused more severe pathology. Those findings shed light on a human selenium-deficiency disease, a cardiomyopathy known as Keshan disease, named after the area in northeast China where it was endemic. The disease showed a seasonal variation, suggesting a viral cofactor that was later identified as coxsackievirus B3. When the population was supplemented with selenium, the incidence of Keshan disease decreased dramatically.