THE EFFECT OF AZADIRACHTIN ON FRESH ISOLATES OF TRYPANOSOMA-CRUZI IN DIFFERENT SPECIES OF TRIATOMINES

The effect of azadirachtin was investigated using three different fres h isolates of Trypanosoma cruzi and five different triatomine species which were infected as third-instar larvae. The two T. cruzi strains w hich originated from sylvatic Triatoma vitticeps showed a high prevale nce after the molt to the fifth instar in Panstrongylus megistus and R hodnius neglectus and a low prevalence in Triatoma infestans and Rhodn ius robustus. The third T. cruzi strain originating from a patient in Piaui showed a high prevalence in P. megistus, R. neglectus and T. inf estans and a low prevalence in Triatoma sordida. Feeding the infected fifth instars with azadirachtin-supplemented blood (1 mu g/ml) resulte d 20 days later in some parasite/vector combinations in an increase, i n other a decrease or an unchanged number of T. cruzi in comparison to bugs fed with unsupplemented blood.