Selenium and viral virulence

A mouse model of coxsackievirus-induced myocarditis is being used to invest igate nutritional determinants of viral virulence. This approach was sugges ted by research carried out in China which showed that mice fed diets compo sed of low selenium ingredients from a Keshan disease area suffered more ex tensive heart damage when infected with a coxsackie B-4 virus than infected mice fed the same diet but supplemented with selenium by esophageal intuba tion. Selenium deficiency in our mice increased the virulence of an already virulent strain of coxsackievirus B-3 (CVB3/20) and also allowed conversio n of a non-virulent strain (CVB3/0) to virulence. Such conversion of CVB3/0 was accompanied by a change in the viral genome to more closely match that of the virulent virus, CVB3/20. As far as the authors are aware, this is t he first report of host nutrition influencing the genetic make-up of an inv ading pathogen. Nutritionists may need to consider this mechanism of increa sed viral virulence in order to gain a better understanding of diet/infecti on relationships.