CONICET | Buscador de Institutos y Recursos Humanos

The assemblage of arthropods and helminths (ticks, mites, fleas, nematodes, and flatworms) present in sigmodontine rodents (Cricetidae) from a broad wetland area of the Río de la Plata, Argentina was studied. A total of 250 sigmodontines were captured during a two years sampling period: Scapteromys aquaticus and Oxymycterus rufus were the most abundant hosts, followed by Oligoryzomys nigripes, Akodon azarae, Oligoryzomys flavescens, and Deltamys kempi. There were 33102 parasites collected, corresponding with Rhopalopsyllidae fleas (Siphonaptera), Hoplopleuridae lice (Phtiraptera), Laelapidae and Macronyssidae mites, Ixodidae ticks, and Trombiculidae chiggers (Acari), the trematodes Echinostomidae, Microphallidae, and Dicrocoelidae, the flatworm Ciclophyllidea, the nematods Trichuridae, Spiruridae, Onchocercidae, Physalopteridae, Aspidoderidae, Oxyuridae, and Nippostrongylinae, and the thorny-headed worm Acanthocephala. A list of arthropods and helminths species associated with each rodent species was given, as well the prevalence and mean abundance. New host and geographic records were provided. The wetlands from Río de la Plata displayed a high biodiversity of parasites associated with the sigmodontine rodents. The phenogram of the relationships of the parasite assemblages showed a high value of similarity between both species of Oligoryzomys, and between S. aquaticus and Ox. rufus. Variation of the values observed in the prevalence and the mean abundance of the host-parasite association suggests that environmental barriers could be performing between the rodent populations, or that differential behavior of the host species (i.e. use of microhabitats, tropics behaviors) may influence these indexes. This knowledge may be used to determine targets for biological conservation and ecological impact of parasitism in the area.