SEPG 2053 - Date Awarded 2002
Cross species transmission of microparasites between introduced and native woodland rodents in Ireland
Sandra Telfer, Kevin Bown, Rachel Sekules and Richard Birtles
Abstract
A range of processes can mediate interactions between introduced and native species, including parasitism and disease. Whilst exotic parasites may pose a direct threat to naïve native host populations, introduced parasites or hosts may also influence ecosystems by perturbation of established host-parasite systems. Despite the potentially important role of parasites in invasions, there have been relatively few empirical studies.
This study investigated the prevalence of flea-transmitted haemoparasites of the genus Bartonella in Irish populations of woodland rodents. Bank voles (Clethrionomys glareolus) were introduced to the south-west of Ireland between 1945 and 1960. In invaded areas, bank voles are sympatric with wood mice (Apodemus sylaticus), Ireland’s only native small woodland rodent. By sampling sites across the invasion front we investigated whether Bartonella species and/or strains were introduced into Ireland with the bank voles and whether bank voles have affected the epidemiology of Bartonella strains native to Irish wood mice.
Bartonella infections were detected either side of the front but occurred exclusively in wood mice. Thus Bartonella species appear not to have accompanied bank voles to Ireland. Moreover, it seems that bank voles are not infected with the Bartonella species already present in Ireland, despite all three of the Bartonella species we encountered infecting both bank voles and wood mice in the U.K. Two hypotheses for the non-susceptibility observed in Ireland can be proposed; either the Bartonella strains present in Ireland are not able to exploit bank voles or Irish bank voles are innately resistant to bartonellae.
Despite the fact that Irish bank voles are not a competent reservoir host, their introduction has affected wood mouse-Bartonella dynamics, with the infection prevalence declining significantly with increasing bank vole density. Analyses reveal that flea prevalence in wood mice increases with wood mouse density in areas without bank voles, whilst flea prevalence decreases with density in invaded areas. The results are consistent with the dilution effect model for vector-transmitted parasites. This study demonstrates that introduced species may initiate significant effects on host-parasite systems.
Papers Published
Papers here: Disruption of a host-parasite system following the introduction of an exotic host species
| 
AREA OF INTEREST:
Home
