Implications of raccoon latrines in the epizootiology of Baylisascariasis

Raccoons (Procyon lotor) frequently establish defecation sites, termed latr ines, on large logs, stumps, rocks, and other horizontally oriented structu res/surfaces. These latrines are important foci of infective eggs of Baylis ascaris procyonis, a nematode parasite of raccoons which is pathogenic to n umerous species of mammals and birds. To examine the role of raccoon latrin es in this animal-parasite interaction, we documented animal visitations to raccoon latrines in two large forested tracts and two woodlots in Indiana (USA) during 1994 and 1995. Species richness of vertebrate visitors did not differ between sites or years, but species composition differed by site an d year. Fourteen mammal and 15 bird species were documented visiting raccoo n latrines. Small granivorous mammals, including white-footed mice (Peromys cus leucopus), eastern chipmunks (Tamias striatus), and tree squirrels (Sci urus carolinensis, S. niger, Tamiasciurus hudsonicus) were the most common visitors to latrine sites. White-footed mice, chipmunks, white-breasted nut hatches (Sitta carolinensis), and opossums (Didelphis virginiana) were phot ographed foraging on undigested seeds in raccoon feces. Active foraging at latrines also was shown experimentally; seeds embedded in raccoon feces wer e removed at a greater rate at latrine sites than at nonlatrines. We conclu de that raccoon latrines are visited routinely by a variety of vertebrates, especially small granivorous rodents and birds which forage for seeds in r accoon feces, and that raccoon latrines are probable sites of transmission of B, procyonis to susceptible mammals and birds.