Amblyomma triste Koch, 1844 (Acari: Ixodidae): Hosts and seasonality of the vector of Rickettsia parkeri in Uruguay.

JOSÉ M. VENZAL, AGUSTÍN ESTRADA-PEÑA, OSCAR CASTRO, CARLOS G. DE SOUZA, MARÍA L. FÉLIX, SANTIAGO NAVA, ALBERTO A. GUGLIELMONE.

VETERINARY PARASITOLOGY

Año: 2008 vol. 155 p. 104 - 109

0304-4017

Amblyomma triste Koch, 1844, the tick species most frequently involved in human bites in Uruguay, has been implicated as avector of human rickettsiosis. Seasonal abundance of adult A. triste was examined by standard flagging at three sites where humantick bites and cases of the disease have been reported. Adult tick activity occurred from August to February (end of winter to midsummer in the southern hemisphere) with a peak in spring. Activity declined in step with decreasing temperatures and photoperiodduring winter. This period of activity coincides with seasonal outbreaks of human rickettsiosis in the region. In a small mammalsurvey, the Sigmodontinae rodents Scapteromys tumidus (Waterhouse, 1837) and Oxymycterus nasutus (Waterhouse, 1837) and thesmall marsupial Monodelphis dimidiata (Wagner, 1847) were the main hosts for immature A. triste. Immature ticks were observedon hosts in November, well within the period of peak adult abundance. In stored collections, immature ticks were most oftencollected from January to March. These data suggest that one generation might be completed in 1 year. The main animal host foradult A. triste at our study sites was the domestic dog. Humans were afflicted by the tick in rural and suburban settlements whereother host animals are scarce or extinct and where dogs are common.