The genetic variability of Triatoma infestans and Trypanosoma cruzi
populations was studied by isoenzyme analysis in two distinct areas of
Arequipa province (Peru); one, Santa Rita de Siguas, being an endemic area
for Chagas' disease, the second, Arequipa, recently infected. Analysis of
T. infestans genetic variability indicates, (i) temporal stability of
genotypes found in Santa Rita de Siguas, (ii) high genetic differences
between Arequipa and Santa Rita de Siguas populations suggesting minor
contact between them, (iii) multiple origin of the T. infestans population
in Arequipa, and (iv) poor dispersal capacity of T. infestans: the
panmictic unit could be reduce to a house. Parasite isoenzyme analysis was
performed in 29 Peruvian stocks of T. cruzi, mainly isolated from bugs
taken in a single locality, Santa Rita de Siguas. The results show, (i) a
high genetic polymorphism, (ii) nine different multilocus genotypes were
detected and clustered in two different clades, (iii) most of the parasite
isolates pertained to one of the clade and were genetically similar to
those analyzed 12 years before. This sample allowed the study of the mating
system of T. cruzi in strict sympatic conditions and gave more strength to
the hypothesis of the clonal structure of T. cruzi populations.
