Dengue virus infections are a serious public health problem worldwide. Aedes aegypti is the primary vector of dengue in Cuba. As there is no vaccine or specific treatment, the control efforts are directed to the reduction of mosquito populations. The indiscriminate use of insecticides can lead to adverse effects on ecosystems, including human health. The sterile insect technique is a species-specific and environment-friendly method of insect population control based on the release of large numbers of sterile insects, ideally males only. The success of this technique for the sustainable management of agricultural pests has encouraged its evaluation for the population suppression of mosquito vector species. Here, we describe an open field trial to evaluate the effect of the release of irradiated male Ae. aegypti on a wild population. The pilot trial was carried out in a suburb of Havana and compared the mosquito population density before and after the intervention, in both untreated control and release areas. The wild population was monitored by an ovitrap network, recording frequency and density of eggs as well as their hatch rate. A significant amount of sterility was induced in the field population of the release area, as compared with the untreated control area. The ovitrap index and the mean number of eggs/trap declined dramatically after 12 and 5 weeks of releases, respectively. For the last 3 weeks, no eggs were collected in the treatment area, clearly indicating a significant suppression of the wild target population. We conclude that the sterile males released competed successfully and induced enough sterility to suppress the local Ae. aegypti population.
To determine larvicidal activity of the essential oil, hydrolat and botanical extracts derived from leaves of Pseudocalymma alliaceum on mosquito larvae of Culex quinquefasciatus. Groups of twenty larvae were used in the larvicidal assays. The mortality, relative growth rate, the larval and pupal duration and viability was estimated. The essential oil was analyzed by solid phase microextraction using gas chromatography coupled to mass spectrometry. Essential oil at 800 ppm showed larvicidal activity at 24 h with lethal values of LC50 and LC90 of 267.33 and 493.63 ppm. The hydrolat at 20% and 10% on 2nd stage larvae showed 100% effectiveness after 24 h. The aqueous extract at 10% had a relative growth index of 0.58, while the ethanolic and methanolic extract obtained values of 0.76 and 0.70 and control reached 0.99. Larvae treated with 10% of methanol, ethanol and aqueous extract showed a reduction in larval duration of 5.00, 2.20 and 4.35 days; ethanol extract at 1% provoke decrease of 2.40 days in the development and exhibited an increment of 3.30 days when treated with 0.01%. Aqueous, ethanol and methanol extracts at 10% reduced in 6.15, 3.42 and 5.57 days pupal development. The main compounds were diallyl disulfide (50.05%), diallyl sulfide (11.77%) and trisulfide di-2-propenyl (10.37%). The study demonstrated for the first time, the larvicidal activity of the essential oil and hydrolat of Pseudocalymma alliaceum; aqueous, ethanol and methanol extracts inhibited the normal growth and development of mosquito larvae, prolonging and delaying larval and pupal duration.
Dengue virus infections are a serious public health problem worldwide. Aedes aegypti is the primary vector of dengue in Cuba. Since there is no vaccine or specific treatment, the control efforts are directed to reduce mosquito populations. The indiscriminate use of pesticides can lead to increase insecticide resistance as well as adverse effects on human health. The sterile insect technique is a species-specific and environmental friendly method of insect control based on the release of large numbers of sterile males. The success of this technique in sustainable control of agricultural pests has encouraged its evaluation for mosquito control. Here, we describe an open field trial to evaluate the effect of the release of irradiated males on a wild population of Aedes aegypti. The case-control study was performed in a suburb of Havana, and compared the mosquito population before and after the intervention, in both control and treated areas. The wild population was monitored by an ovitrap network, recording frequency and density of eggs as well as their hatch rate. A significant induced sterility was observed in the field population, compared to the control. The ovitrap index and the mean eggs/ trap declined dramatically after an expected lag period of twelve and five weeks, respectively. For the last three weeks, no egg was collected in the treated area, evidencing a significant suppression of the wild population. We conclude that the sterile males released competed successfully, and induced enough sterility to suppress the local Aedes aegypti population.
Background: Aedes aegypti, the primary vector of dengue, chikungunya, and Zika viruses, poses a significant public health threat worldwide. Traditional control methods using insecticides are increasingly challenged by resistance and environmental concerns. The sterile insect technique (SIT) offers an eco-friendly alternative that has been successfully applied to other insect pests. This article aims to briefly review Ae. aegypti management in Cuba, highlighting the accomplishments, challenges, and future directions of the SIT. Main body: Here we provide a brief summary of the extensive history of Ae. aegypti control efforts in Cuba. After a successful eradication campaign in the 1980s, a resurgence of dengue cases has been observed in recent years, suggesting that traditional control methods may have limited effectiveness under current conditions. In response, Cuba initiated a phased approach to develop and evaluate the feasibility of SIT for Ae. aegypti control, starting in 2008. Initial research focused on Ae. aegypti mating behavior and sterilization methods, followed by successful laboratory and semi-field trials that demonstrated population suppression. The first open-field trial in 2020 confirmed the efficacy of the SIT in reducing Ae. aegypti populations under real-world conditions. Currently, the research is in a phase involving a cluster-randomized superiority-controlled trial. This planned trial will compare the standard vector control program with the same program augmented by the SIT, aiming to assess the impact of the SIT on dengue incidence as the primary outcome. Implementing robust epidemiological trials to evaluate the effectiveness of the SIT is complex due to potential spillover effects from mosquito and human movement across study areas. Additionally, conducting the SIT requires significant development and operational investments. Despite these challenges, the ongoing Cuban trial holds promise for establishing the SIT as an effective and sustainable tool for Ae. aegypti control and for reducing the burden of mosquito-borne diseases. Conclusions: The phased evaluation conducted in Cuba confirms the efficacy of the SIT against Ae. aegypti, highlighting its potential for sustainable mosquito-borne disease management. The effective implementation of multi-site trials will be crucial in providing evidence of the potential of the sterile insect technique as part of a strategy to reduce the incidence of arboviral diseases. Graphical