A longitudinal study of an endemic disease in its wildlife reservoir: cowpox and wild rodents

Cowpox is an orthopoxvirus infection endemic in European wild rodents, but with a wide host range including human beings. in this longitudinal study w e examined cowpox in two wild rodent species, bank voles Clethrionomys glar eolus and wood mice Apodemus sylvaticus, to investigate the dynamics of a v irus in its wild reservoir host. Trapping was carried out at 4-weekly inter vals over 3 years and each animal caught was uniquely identified, blood sam pled and tested for antibodies to cowpox. Antibody prevalence was higher in bank voles than in wood mice and seroconversion varied seasonally, with pe aks in autumn. Infection was most common in males of both species but no cl ear association with age was demonstrated. This study provides a model for studying other zoonotic infections that derive from wild mammals since othe r approaches, such as one-off samples, will fail to detect the variation in infection and thus, risk to human health, demonstrated here.