Evaluación de la persistencia de una formulación comercial de Bacillus sphaericus en criaderos naturales de anofelinos vectores de malaria en estado Bolívar, Venezuela

sifontes municipality in bolivar state is the main malaria endemic area in venezuela. during the last five years an annual average of 14,000 cases has been reported, reaching 13,450 during 2008, resulting in an epidemic situation. a commercial formulation of bacillus sphaericus neide (vectolex cg 7.5%), was evaluated in larval habitats of anopheles marajoara, an. triannulatus and an. braziliensis. two experiments were carried out in a lagoon and a pasture inundated area, 2 and 3 gr/m2 doses were evaluated during 60 and 90 days. the results point out that there are differences in the persistence depending on the type of larval habitat and anopheline species. the general trend indicated that for all the species the persistence of the vectolex, therefore the reduction of the larval population was 100% during the first week. however, it felt under 40% after day 28, then recovered by day 45, and remaining around 40% for 90 days with both doses. a similar pattern was observed for an. marajoara, whereas for an. triannulatus the efficacy remained around 80% during 90 days only at 3 gr/m2. with an. braziliensis there was 100% persistence until day 14 with both doses, for then felt abruptly without recovering. this is the first time that b. sphaericus was evaluated for these anopheline species in venezuela, considering these results promissory for the malaria control program.