In México, the role of mammals in the transmission
cycle of
Trypanosoma cruzi
is poorly known. In the State of Yucatán, an endemic area of Chagas
disease, both
Didelphis virginiana
and
D. marsupialis
occur sympatrically. However, until now, only the former species had been
found infected with
T. cruzi
. To evaluate the role of D. virginiana in a peridomestic transmission,
nine periods of capture-recapture were performed around the village of Dzidzilché,
Yucatán. The sex, age, reproductive status, location, and presence
of infection with
T. cruzi
were recorded for each opossum. The chromosome morphology was used to identify
the opossum species.
T. cruzi
was identified by the presence of pseudocysts of amastigotes in cardiac
muscle fibers of Balb/c mice inoculated with strains isolated from opossums.
However, xenodiagnosis was the best diagnostic method. Triatoma dimidiata,
the vector, were collected in and around the opossums' nests, and human
dwellings; and were checked for
T. cruzi
. From 102 blood samples of
D. virginiana
examined 55 (53.9%) were positive to
T. cruzi
, the only two
D. marsupialis
captured were negative. Significant differences were found between infection,
and both sex and reproductive condition. Eight out of 14 triatomines collected
in peridomestic nests (57.1%), and 32 of 197 captured inside houses (16.3%)
were found infected, suggesting a peridomestic transmission. The statistically
high abundance of infected opossums and triatomines during the dry season
(March to May) suggested the existence of a seasonality in the peridomestic
transmission of
T. cruzi
in Dzidzilché.
