Digenean parasites of Sigmodontinae rodents from Argentina: a list of species, new host, and geographical records

Update of Dicrocoeliidae (Digenea) parasitizing rodents from the Americas with a description of a new Platynosomoides species from Argentina

Digeneans are common parasites of small mammals. Dicrocoeliidae is a family with a cosmopolitan distribution, with 18 genera previously recorded from mammals in the Americas, six of them parasitizing rodents in Argentina. In this study, an updated compilation is provided of Dicrocoeliidae from rodents in the Americas. Also, a new Platynosomoides species is described parasitizing the cricetid rodent Akodon montensis of the Atlantic Forest in Argentina. Digital repositories were used to search for Dicrocoeliidae from rodents in the Americas. Rodents were collected in four localities of the Atlantic Forest, Argentina. Digeneans were removed from the rodent's bile duct, and conventional studies were used for the morphological description. A total of 15 Dicrocoeliidae species were found parasitizing 18 rodent species from eight countries in the Americas. The new species of Platynosomoides from Akodon montensis differs from the other two species of genus by the size of body, testes, ovary, cecum length and position and length of the vitelline bands. Dicrocoeliidae show growing diversity, and the compilation of species in a rodent host base allows a clearer comparison and identification of new taxa in the future.

Detection of Neorickettsia sp. in Oligoryzomys flavescens rodent from a protected urban area in Buenos Aires City (Argentina)

Rodents play an important role in vector-borne pathogens cycle. To detect Anaplasma, Ehrlichia, Neorickettsia, Rickettsia and Borrelia species in rodents from a protected urban area in Buenos Aires City (Argentina) were analyzed 203 organ pools of Mus musculus, Oligoryzomys flavescens, Rattus norvegicus, Deltamys kempi and Scapteromys aquaticus by PCR. Only one O. flavescens (1.2%) was positive by PCR for 16S rRNA fragment for the Anaplasmataceae family and the sequence had 99.7% identity with Neorickettsia risticii. Plus, the sequence obtained for a fragment of the p51 gene for the genus Neorickettsia from positive sample had 95.3-96.1% identity with N. risticii found previously in bats Tadarida brasiliensis from Buenos Aires City. Our study presents the first finding of Neorickettsia in rodents from natural environment, but further studies are necessary about these vector-borne bacteria and the rol of rodents in its epidemiology.