[First finding of Chagas disease vectors associated with wild bushes in the Metropolitan Region of Chile].

BACKGROUND

Insects of the subfamily triatominae are the biological vectors of Trypanosoma cruzi, the causal agent of Chagas disease.

AIM

To search for wild colonies of triatomines in the Metropolitan Region of Chile.

MATERIAL AND METHODS

Ad hoc traps were placed in two endemic zones of the Metropolitan Region of Chile, during 30 nights. The dejections of 16 T infestans and 43 M spinolai specimens were examined under the microscope, searching for live metacyclic trypomastigotes. A polymerase chain reaction (PCR) was performed in macerates of all insects looking for T cruzi DNA.

RESULTS

A total of 269 bugs were captured. Forty four were Triatoma infestans and 225 were Mepraia spinolai. They were not syntopic, since T infestans was restricted to a Southern zone (Calera de Tango) while M spinolai was only found in the Northern zone (Til-Til). Both species were found associated to terrestrial bromeliads (Puya sp) but M spinolai was also detected in stony grounds. Microscopic examination of dejections yielded a trypano-triatomine index of 56.3 and 32.6 for T infestans and M spinolai, respectively. PCR detected T cruzi DNA in 41 and 43% of T infestans and M spinolai specimens, respectively.

CONCLUSIONS

The finding of T infestans in a wild habitat is noticeable. This is the first report of such phenomenon in Chile. The high infection rates with T cruzi, explains the maintenance of Chagas disease wild cycle in Chile.