Bloodmeal host preference of Triatoma sanguisuga (Hemiptera: Reduviidae) from Louisiana

Although rare in occurrence, autochthonous transmission of Trypanosoma cruzi, the etiologic agent of Chagas disease, within the United States is an area of growing concern. The arthropod vector that has been most implicated in these cases is the Eastern Bloodsucking Conenose (Triatoma sanguisuga).  In southeastern Louisiana, the prevalence of T. cruzi in the adult population of T. sanguisuga has been found to be near 60%. Given this high prevalence, it seems likely that ecological and behavioral characteristics of the vector prevent frequent transmission of the parasite to humans. However, little is known with respect to the natural ecology of T. sanguisuga, including whether it is closely associated with a specific mammalian host as has been found for other related Triatoma species in the southwestern United States.  We undertook a multi-year, ecological study of the species to better understand its preferred blood meal sources. Because sylvatic rodents have been found to be the principal host for other Triatoma species, in order to test them for T. cruzi, a sample of rodents was taken from a known T. sanguisuga habitat. Over three years, a total of 59 rodents were collected from the same parcel of land and tested for infection by PCR for T.cruzi kDNA. To complement these collections, late instar and adult T. sanguisuga specimens were also collected from this area and analyzed by PCR for both T. cruzi infection and blood meal source. This analysis of > 500 specimens is underway and will be presented. Preliminary results from an initial sample of thirty rodents suggest a relatively high prevalence (60%) of T. cruzi infection. The three species of rodents contained in this sample tested positive for T. cruzi at varying levels: Neotoma floridana (67%), Peromyscus gossypinus (58%), and Mus musculus (0%).  This study will allow us to better understand the host feeding preferences of T. sanguisuga and therefore gain a more complete understanding of the sylvatic transmission cycle of T. cruzi in the southcentral United States.