EFFECTS OF AZADIRACHTIN ON RHODNIUS-PROLIXUS - IMMUNITY AND TRYPANOSOMA INTERACTION

The effects of azadirachtin, a tetranortriterpenoid from the neem tree Azadirachta indica J., on both immunity and Trypanosoma cruzi interac tion within Rhodnius prolixus and other triatomines, were presented. G iven through a blood meal, azadirachtin affected the immune reactivity as shown by a significant reduction in numbers of hemocytes and conse quently nodule formation following challenge with Enterobacter cloacae beta12, reduction in ability to produce antibacterial activities in t he hemolymph when injected with bacteria, and decreased ability to des troy the infection caused by inoculation of E. cloacae cells. A single dose of azadirachtin was able to block the development of T. cruzi in R. prolixus if given through the meal at different intervals, togethe r with, before or after parasite infection. Similarly, these results w ere observed with diferent triatomine species and different strains of T. cruzi. Azadirachtin induced a permanent resistance of the vector a gainst reinfection with T. cruzi. The significance of these data is di scussed in relation to the general mode of azadirachtin action in inse cts.