51 research outputs found
Inter-relation of sylvatic and domestic transmission of Trypanosoma cruzi in areas with and without domestic vectorial transmission in Minas Gerais, Brazil
During the period 1980-1986, we captured triatomine bugs and mammalian
reservoir hosts from sylvatic and domestic situations in different
municipalities of the State of Minas Gerais. Trypanosoma cruzi was
isolated from captured bugs, mammals and patients. After cultivation in
LIT medium, the electrophoretic enzyme profiles were determined. We
obtained a total of 32 parasite isolates from regions with active
domestic transmission, and 24 isolates from areas under control. For
the first areas the results suggest introduction of T. cruzi from
sylvatic habitats, through incursion of infected opossums and/or
sylvatic T. sordida, which appears to have given rise to at least one
acute human infection. Of particular interest is the finding of
sylvatic opossums and a T. sordida nymph infected with ZB, that could
indicate return of parasites from chronic human infections to sylvatic
transmission cycles. For the areas under control we also interpret the
results as interaction between sylvatic and domestic cycles of
transmission, here through the invasion of houses by bugs carrying the
Z1 zymodeme from the sylvatic environment. The Multivariate
Correspondence Analysis gives a spatial description between the
different parasite isolates and confirms the existence of a bridge in
the opposite direction in the region with active vectorial transmission
including the exporting of Z2 through the peridomestic environment into
the sylvatic cycle. For the other areas this bridge corresponds
especially to Panstrongylus megistus, importing Z1 into the domestic
environment
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