Phylogenetic and ecological factors affecting the sharing of helminths between native and introduced rodents in Central Chile.

In order to analyse the effect of hosts' relationships and the helminthic load on the switching of parasites between native and introduced hosts, we sampled rodents belonging to two suborders from Central Chile. We compared the number of helminthic species shared between murids (introduced) and cricetid (native, same suborder) rodents to those shared between murids and hystricomorphs (native, different suborder), and we assessed the association between parasitic presence, abundance and geographical dispersion in source hosts to the presence and abundance in recipient hosts. Introduced rodent species shared more helminth species with cricetid rodents than with non-cricetids. Presence and abundance in recipient hosts was not associated with the prevalence and mean abundance in source hosts' population. The mean abundance of parasites in source hosts throughout the territory and wider dispersion was positively associated with the likelihood of being shared with a recipient host. Closer relationships between native and introduced hosts and high parasitic abundance and dispersion could facilitate host switching of helminths between native and introduced rodents. This work provides the first documentation of the importance of parasitic abundance and dispersion on the switching of parasites between native and introduced hosts.

Natural Infection of Leptospira Species in the Native Rodents Degu ( Octodon degus ) and Darwin's Pericote ( Phyllotis darwini ) in Mediterranean Ecosystem of Chile.

We report natural infections by pathogenic Leptospira of two rodent species endemic to Chile: the degu ( Octodon degus ) and Darwin's pericote ( Phyllotis darwini ). We detected Leptospira DNA in kidney and urine samples taken in different years and sites, reaching 33% infection. The effects of infection in these species requires further evaluation.