We report the first record of Litomosoides pardinasi in native and exotic rodents from Chile. Litomosoides pardinasi, described in the Argentine Patagonia parasitizing Phyllotis xanthopygus and Oligoryzomys longicaudatus, was found in Chile parasitizing the peritoneal and thoracic cavities of O. longicaudatus (prevalence (P)= 18.9%, mean intensity (MI)= 57.3) and Phyllotis darwini (P= 4.2%, MI= 10), and in the peritoneal cavity of Rattus rattus (P= 1.24%; MI= 22.5). Total P in native rodents from Chile was significantly lower than in Argentina, while the total MI was higher. Prevalence and MI of L. pardinasi in O. longicaudatus from Chile and Argentina showed non-significant differences; prevalence in P. darwini from Chile was significantly lower than in P. xanthopygus from Argentina and than in Chilean O. longicaudatus. Our results, together with those from Argentina, support the hypothesis that L. pardinasi is well established in O. longicaudatus, but seems to be recently acquired by P. darwini and the exotic R. rattus. Considering the known host distribution of Litomosoides species among the sigmodontines, our results also support the hypothesis that L. pardinasi first colonized the Oryzomyini tribe and later, by different phenomena of host-switching, colonized the Phyllotini tribe and the exotic R. rattus.

Litomosoides pardinasi es registrada por primera vez en roedores nativos y exóticos de Chile. La especie Litomosoides pardinasi, parásita de Phyllotis xanthopygus y Oligoryzomys longicaudatus en la Patagonia Argentina, fue encontrada en Chile parasitando la cavidad torácica y abdominal de O. longicaudatus (prevalencia (P)= 18.9%, intensidad media (MI)= 57.3) y de Phyllotis darwini (P= 4.2%, MI= 10), y la cavidad abdominal del roedor exótico Rattus rattus (P= 1.24%; MI= 22.5). La P total en roedores nativos de Chile fue significativamente menor que la P de Argentina, en tanto la MI total fue significativamente mayor. La P y MI de L. pardinasi en O. longicaudatus de Chile y Argentina no mostraron diferencias significativas; la P en P. darwini de Chile fue significativamente menor que la de P. xanthopygus de Argentina y que la de O. longicaudatus de Chile. Considerando la distribución de las especies de Litomosoides entre los sigmodontinos, estos resultados apoyan la hipótesis que L. pardinasi está bien establecida en O. longicaudatus y que posiblemente haya sido recientemente adquirida por P. darwini y R. rattus. Así, L. pardinasi colonizó primero a la Tribu Oryzomyini y posteriormente por un fenómeno de cambio de hospedero a la Tribu Phyllotini y a R. rattus.

Triatoma infestans is one of the main domestic vectors of Chagas disease. Reports of wild habitat occurrences have recently increased. In Chile, after a successful elimination campaign of T. infestans domestic infestation, a sylvatic focus was reported in bromeliads in the metropolitan region. Here, we report a new focus of sylvatic T. infestans inhabiting rock piles in the Valparaíso region in central Chile. All T. infestans captured were nymphal instars living among the stones, which were inhabited by several mammal species, along with the sylvatic triatomine vector Mepraia spinolai. We found a prevalence of infection with Trypanosoma cruzi of 36.54% in T. infestans, similar to the previous report for sylvatic specimens from bromeliads. Sylvatic populations of T. infestans should be studied at different geographic scales to elucidate their role in the maintenance of the sylvatic transmission cycle of T. cruzi and their possible role in threatening the domestic elimination of this vector. This information should be used to re-design the control programs in Chile to avoid the re-establishment of the domestic cycle.