Cardiovirus) are pathogens of rodents and include a murine encephalomyocarditis virus and Theiler's virus and related strains (species Theilovirus), the latter serving as laboratory models of the pathogenesis of multiple sclerosis in mice (1) . The existence of specifi c human cardioviruses was suspected in the 1960s in conjunction with a rare infectious neurodegenerative disease known as Vilyuisk encephalitis (2, 3) . Recently, human cardioviruses (hCVs) were identifi ed in archived diagnostic cell culture supernatants (4) and in clinical samples from children with diarrhea or respiratory infection (5, 6) . Up to 8 different putative hCV types have since been characterized in human feces (7) .