Controle do Aedes aegypti na fase de ovo

Abstract

The vector control of Aedes aegypti in Brazil has been a challenge in recent decades, and nowadays it has become more critical, since, in addition to dengue, other arboviruses, such as zika and chikungunya, are now transmitted by this vector, causing great medical, social, and economic impacts. As about 80% of the egg breeding sites are located in houses and peridomicile regions, it is important to have methods that work in thesefoci, involving joint actions between population and government agencies. Different strategies have been used to combat the vector in its larval and adult stages, but little effective exist to combat its egg stage, which remains viable in nature for more than a year, being a factor for the dissemination of Ae. aegypti. Strategies of combating the vector, such as applying fire, burning breeding grounds, preventing them from being covered with water or crushing the eggs have shown little practicality and difficulty in executing them. A steam and heat emitting household appliance (Professional Clean Shark vaporizer, model S3901BZ11 in dust and scrub mode) and a conventional hair dryer (at high-power mode) were used to apply dry heat on eggs of the Rockefeller strain of Ae. aegypti. In all experiments, we observed that both sprayings using the two steam modes (scrub and dust) and the application of dry heat were able to inhibit egg hatching in varying degrees when compared to the control group with statistical significance. The dust mode, where the vapor was less intense, was able to inhibit the hatching of 94.59% of the 1901 treated eggs and presented a relative risk (RR) of 5.9 (95% CI: 5.12 - 6.80). The scrub mode, where the steam was more intense, inhibited the hatching of 58.91% of the 1509 treated eggs and presented a RR of 3.7 (95% CI 3.17 - 4.26) and, finally, the hair dryer was able to inhibit the hatching of 57.97% of the 728 treated eggs showed RR of 3.6 (95% CI 3.10 - 4.26). Therefore, it was proposed to combat the mosquito in the egg stage in its place of posture, without the use of insecticides, without environmental pollutants, and could be adopted by all. The application of these methods directly to eggs in domestic and peridomicile foci or in objects that can house and transport eggs from the vector using devices already on the market and easy to handle, without the use of insecticides or environmental pollutants, can impede the transmission cycle of arboviruses, eliminating the viability of most of the vector foci.