Abstract

ACOSTA, N et al. Isoenzyme profiles of triatoma infestans populations from eastern and western regions of Paraguay. Mem. Inst. Investig. Cienc. Salud [online]. 2002, vol.1, n.1, pp.58-62. ISSN 1812-9528.

ABSTRACT Triatoma infestans populations from 4 departments endemic for Chagas disease, corresponding to the two main regions of Paraguay, were characterized by isoenzymes electrophoresis in cellulose plates. Twenty four specimens from the Chaco region were studied: twelve from Boquerón and twelve from Pte. Hayes. Twenty specimens from the Eastern region were studied: ten from Cordillera and ten from Paraguari. Six enzyme systems were analyzed: alfa-GDP, GPI, PGM, 6PGD, IDH and MDH which involve 8 loci. Only alfa-GDP system showed differences and two phenotypes were found: phenotype 1 was found in 86.36% of the specimens and phenotype 2 in 13.63%. Phenotype 2 was only observed in specimens from the Chaco. In the other systems, the same phenotypes were obtained in all specimens. Consequently, it can be said that the genetic variability found was low. Specimens of the Eastern Region were all the same without any differences between domiciliary and peridomiciliary populations. The marked monomorphism shown by this study would agree with other authors who suggest an evolution from a small initial population (founder effetc) and a genetic drift process for T. infestans populations. The small variability observed could constitute an advantage for the chemical contro of these insectsl, as the apperance of resistant variants, which could give origin to resistans individuals, is less probable. However, it should be pointed out the difference found in the Chaco specimens.

Keywords : Isoenzymes; triatoma infestans; Paraguay; monomorphism.

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