The effects of cowpox virus on survival in natural rodent populations: increases and decreases
Sandra Telfer, Department of Veterinary Pathology, Leahurst Field Station, University of Liverpool, Chester High Road, Neston, Cheshire CH64 0TF, UK. Fax: 0151 7946005; E-mail: firstname.lastname@example.org
- 1The effect of cowpox virus on survival in two rodent hosts was investigated using nearly 4 years of longitudinal data from two sites.
- 2We investigated whether an individual's probability of infection influenced the probability of surviving the next month. We also investigated the effect at the population level, examining whether, in addition to seasonal effects, changes in cowpox prevalence explained further temporal variation in survival rates.
- 3In bank voles, but not wood mice, individuals with high probabilities of infection survived better than uninfected animals.
- 4At the level of the population, the effect of infection on survival varied through the year in both species. Survival rates in late summer increased with cowpox prevalence, whilst survival rates in winter decreased with cowpox prevalence.
- 5We discuss why parasites such as cowpox virus may increase or decrease host survival and why the effect may depend on the time of year.