Oviposition preference and egg eclosion in different salt concentrations in the coastal malaria vector Anopheles aquasalis Curry.

Anopheles aquasalis is the main malaria vector in Sucre State, Venezuela. The larvae of this species are saltwater tolerant. The effects of different concentrations of salt on oviposition preference and egg survival were studied under laboratory conditions. Choice experiments with salt concentrations of 0, 10, 20, 30, and 40% in bottled water were set up for individual adult females and the number of eggs laid in each salt concentration was noted. Egg survival, as inferred by the number of hatched larvae also was determined for each salt concentration. Females preferred to oviposit in freshwater and rejected water salt concentrations of 40%, but they were neither attracted nor repelled by water with 10-30% of salt. Eggs hatched more quickly in the lower salt concentrations, but egg survival was not affected by salt concentrations of up to 20%. Thus, female oviposition preference in An. aquasalis determines egg survival.

Comparison of two commercial formulations of Bacillus thuringiensis var. israelensis for the control of Anopheles aquasalis (Diptera: Culicidae) at three salt concentrations.

Anopheles aquasalis larvae are salt water tolerant, preferring concentrations between 10 and 20 parts per thousand (ppt). The larvicidal efficacy of two formulations of Bacillus thuringiensis var. israelensis (Vectobac-12AS and Bactivec), was investigated against An. aquasalis at salinities of 0, 10, and 20 ppt. A probit analysis was used to calculate the lethal concentrations (LC50 and LC95) for each product at each salinity. The LC50 and LC95 were higher for Bactivec than Vectobac-12AS, and for Bactivec, the LC50 and LC95 increased with salinity. Vectobac-12AS should thus be preferred to Bactivec for An. aquasalis control, especially in saline breeding habitats.

Comparison of two commercial formulations of Bacillus thuringiensis var. israelensis for the control of Anopheles aquasalis (Diptera: Culicidae) at three salt concentrations

Extracts of propolis samples collected in Brazil and Bulgaria were assayed against four Leishmania species - Leishmania amazonensis, L. braziliensis, L. chagasi from the New World, and L. major from the Old World - associated to different clinical forms of leishmaniasis. The composition of the extracts has been previously characterized by high temperature high resolution gas chromatography coupled to mass spectrometry. Considering the chemical differences among the extracts and the behavior of the parasites, it was observed significant differences in the leishmanicidal activities with IC50/1 day values in the range of 2.8 to 229.3 µg/ml . An overall analysis showed that for all the species evaluated, Bulgarian extracts were more active than the ethanol Brazilian extract. As the assayed propolis extracts have their chemical composition determined it merits further investigation the effect of individual components or their combinations on each Leishmania species