Background: Aedes aegypti can transmit arboviruses worldwide, and Bacillus thuringiensis svar. israelensis (Bti)-based larvicides represent an effective tool for controlling this species. The safety of Bti and lack of resistance have been widely reported; however, little is known regarding the impact of the extensive use of these larvicides on the life traits of mosquitoes. Therefore, this study investigated biological parameters, including susceptibility to arbovirus, of an Ae. aegypti strain (RecBti) subjected to 29 generations of exposure to Bti compared with the RecL reference strain. Methods: The biological parameters of individuals reared under controlled conditions were compared. Also, the viral susceptibility of females not exposed to Bti during their larval stage was analysed by oral infection and followed until 14 or 21 days post-infection (dpi). Results: RecBti individuals did not display alterations in the traits that were assessed (fecundity, fertility, pupal weight, developmental time, emergence rate, sex ratio and haematophagic capacity) compared to RecL individuals. Females from both strains were susceptible to dengue serotype 2 (DENV-2) and Zika virus (ZIKV). However, RecBti females showed significantly higher rates of ZIKV infection compared with RecL females at 7 (90% versus 68%, Chi-square: χ² = 7.27, df = 1, P = 0.006) and 14 dpi (100% versus 87%, Chi-square: χ² = 7.69, df = 1, P = 0.005) and for dissemination at 7 dpi (83.3% versus 36%, Fisher’s exact test: P < 0.0001, OR = 0.11, 95% CI 0.03–0.32). Quantification of DENV-2 and ZIKV viral particles produced statistically similar results for females from both strains. Conclusions: Prolonged exposure of Ae. aegypti larvae to Bti did not alter most of the evaluated biological parameters, except that RecBti females exhibited a higher vector susceptibility for ZIKV. This finding is related to a background of Bti exposure for several generations but not to a previous exposure of the tested females during the larval stage. This study highlights mosquito responses that could be associated with the chronic exposure to Bti in addition to the primary larvicidal effect elicited by this control agent. Graphical

In Brazil, public health programs have relied predominantly on chemical insecticides to control Aedes aegypti, Anopheles spp., Culex quinquefasciatus, triatomines, and phlebotomines. Rising vector-borne disease incidence and insecticide resistance (IR) call for a critical appraisal of historical and current control practices. This literature review compiles secondary data produced from 1901 to 2024 obtained from Medline/PubMed, Google Scholar, and governmental notes and reports. Brazil’s vector control progressed from organochlorines (e.g., DDT) to organophosphates, carbamates, pyrethroids, insect growth regulators, microbial larvicides (Bti and Lsp), spinosad, and recently formulations with dual active-ingredient. Ae. aegypti showed widespread resistance to temephos and pyrethroids, decreased susceptibility to pyriproxyfen, and no documented Bti resistance. Anopheles spp. exhibited low to moderate resistance to pyrethroids. Cx. quinquefasciatus resistance is likely influenced by collateral exposure from Aedes control and domestic use. Regarding triatomines and phlebotomines, there was a predominant reliance on pyrethroids; most studies indicate their susceptibility to these compounds. In short, Brazil’s century-long, insecticide-centric strategy has delivered episodic gains but fostered Aedes aegypti resistance. For other species, for which there is no dedicated program for a long period, data on resistance are scarce or nonexistent. Sustainable progress requires strengthened, nationwide IR surveillance and entomological mapping to coordinate cross-program actions.

Background: The use of toxic sugar bait with ivermectin (TSB _Ivermec ) has emerged as a promising strategy for controlling insects that feed on carbohydrates, particularly mosquito species, in areas endemic for arbovirus transmission. The aim of this study was to evaluate the effectiveness of TSB _Ivermec in controlling flies of medical and veterinary importance. We assessed the overall mortality of adults of two species, Peckia ( Sarcodexia ) lambens and Chrysomya megacephala , and the effect of different ivermectin concentrations on fly mortality. Methods: Concentrations of 0.012%, 0.025%, and 0.050% ivermectin diluted in 20% sucrose were tested on groups of 40 adult flies (1:1 male:female), aged 4–8 days. Exposure to TSB _Ivermec lasted for 6 h, and mortality was monitored for up to 96 h and compared to that of a control group with no ivermectin exposure. Results: Both species showed cumulative mortality of 100% at the highest concentration of ivermectin (0.050%), although P. ( S .) lambens was more sensitive to the compound than C. megacephala , with most deaths occurring within the first 24 h. At lower concentrations, mortality ranged from 97 to 81% for P. ( S .) lambens (at 0.025% and 0.012%, respectively), and 78–57% for C. megacephala . Mortality differed significantly between these species ( P < 0.001), but not between the sexes ( P = 0.8). TSB _Ivermec demonstrated high efficacy against both species under semi-field conditions. Conclusions: The results suggest that the 0.050% concentration of ivermectin, which is known to be effective against mosquitoes, is also optimal for the rapid population control of synanthropic flies, enabling its integrated use in highly infested or vulnerable environments, such as health care facilities. Graphical

The use of irradiation in the Sterile Insect Technique (SIT) is a sustainable and environmentally friendly strategy for controlling Aedes aegypti populations by the release of sterile males. However, the potential toxic effects of radiation on mosquito genetic material, as well as the heritability of such damage, remain insufficiently understood. In this study, we evaluated gamma radiation-induced DNA damage (20, 30, 40, and 50 Gy) in male pupae (F0 generation) and assessed the persistence of these effects in subsequent generations (F1 and F2) using the comet assay in hemocytes. In the parental generation, a significant dose–response relationship was observed, with increasing radiation doses associated with higher damage index and damage frequency (p < 0.05). In the F1 generation, both larvae and adults exhibited significantly greater DNA damage than the control group, particularly at doses of 30 and 40 Gy, supporting the inheritance of radiation-induced genomic instability. In the F2 generation, genotoxic effects were attenuated, although residual damage remained detectable in adults, suggesting partial recovery of genomic stability, possibly influenced by DNA repair mechanisms and/or selective pressures. No viable offspring were obtained at 50 Gy, confirming the sterilizing efficacy of higher doses. Integration of comet assay results with micronucleus data and reproductive parameters reinforces the association between DNA damage, mutagenic effects, and reduced fertility. These findings indicate that radiation-induced genotoxic effects may persist beyond the irradiated generation but tend to decline across generations. Overall, this study provides insights into the balance between achieving sterility and preserving biological quality in SIT programs, contributing to optimizing radiation doses and enhancing the safety and efficacy of vector control strategies.

Culex quinquefasciatus is an abundant domestic mosquito in tropical and subtropical areas, and an important disease vector. Despite its major importance as a vector of Wuchereria bancrofti and the significant biting nuisance caused by nocturnal biting, it has never been the target of any large-scale control programs in Brazil. In contrast, Aedes aegypti, the main vector of dengue, Zika, and other viruses to humans, is the target of multiple control programs worldwide. We tested the efficacy of an insecticidal paint, CARBAPAINT 10 (propoxur 1.0%), against Cx. quinquefasciatus using a delivery method where only the room skirting, close to the floor, is treated with black insecticidal paint, a method designed primarily to target Ae. aegypti. Our results showed that the Cx. quinquefasciatus population in Recife was highly susceptible to the insecticide, with 100% mortality in WHO cone tests. In free-flight tests in an experimental room, painted wall skirtings were also effective, especially if black paint was used as mortality rates were significantly higher than with white insecticidal paint (70% and 30%), p < 0,0001). These results indicate that Cx. quinquefasciatus will also be impacted if this approach is eventually used for vector control of Ae. aegypti. While not essential, the ability to impact all mosquitoes that bite humans is an important prerequisite for determining the likelihood of high acceptance of a control approach by target communities.