ABSTRACT
ABSTRACT Brazil has been suffering a dengue (DENV) epidemic in 2019 and 2022 and records cases of Zika (ZIKV) and chikungunya (CHIKV). Londrina city, Paraná, stands out for the number of cases and deaths from dengue. Therefore, this study aimed to verify the density and diversity of mosquitoes present in urban public establishments of Londrina, to analyze their ecological relationships, and to investigate the presence of the DENV, ZIKV, and CHIKV. Ovitraps were installed in outdoor sites in two public establishments in each region of Londrina, while adult culicids were caught indoors with a Nasci aspirator. A total of 5077 eggs were obtained in 77 ovitraps. The South region had the highest infestation while the East had the lowest (Ovitrap Positivity Index: 38% and 25%; Egg Density Index: 67.83 and 19.03, respectively). From eggs, 704 Aedes aegypti females and 71 Aedes albopictus females were obtained, while in the aspiration of adults, 99 A. aegypti and 11 Culex quinquefasciatus were captured, the highest number in the West and the lowest in the North. The DENV-II virus was detected in a pool of 17 A. aegypti females in the West region. The results demonstrate high density of pathogen vector species, mainly A. aegypti, in and around establishments, alerting to the need for constant local entomological surveillance to prevent viral circulation, mainly in crowded places. The presence of A. albopictus around the establishments also alerts to the urbanization of the species and potential participation in the viral circulation, demonstrating the need for constant monitoring.
ABSTRACT
ABSTRACT Aedes (Stegomyia) aegypti is an important vector of dengue, yellow fever, chikungunya and Zika virus. It is well known that resistance monitoring and genetic diversity data help designing the vector control programs. This study aimed to evaluate resistance to pyrethroids (PYs) through the frequency of kdr mutations Val1016IIe and F1534C, and the genetic variation of the mitochondrial gene ND4 in six natural populations of A. aegypti from Paraná - Brazil. Adults were obtained from eggs collected from Alvorada do Sul, Marilena, Maringá, Nova Londrina, Paranavaí and São Carlos do Ivaí. From these adults, 345 were used to identify the 1016 and 1534 sites, and 120 were used to perform the ND4 gene analysis. The studied populations from Paraná showed PYs resistance, low gene flow and genetic diversity. Additionally, a relationship was observed among the haplotypes of populations from the Amazon and Southeastern Brazil, Peru, Mexico, and North America.
ABSTRACT
Abstract Histological effects of polybrominated diphenyl ethers (PBDEs) were observed in Chironomus sancticaroli larvae which underwent acute exposure. 2,2′,4-triBDE (BDE-17), 2,2′,4,4′-tetraBDE (BDE-47) and 2,2′,4,4′,5-pentaBDE (BDE-99) were evaluated at 0.5, 2.0 and 20 μg L-1. Cytoplasm vacuolisation of oenocytes was observed in the larvae exposed to BDE-17 and BDE-47. Cuénot cells were disrupted at the brush border as an effect of the three evaluated congeners highlighting BDE-47 at 2.0 μg L-1; 60% of larvae displayed this disruption. The midgut showed changes in the morphology of apex cells located next to the lumen of region I exposed to BDE-17 and BDE-47, while BDE-99 induced a narrowing of the lumen diameter. Significant cytoplasm vacuolisation of the larvae exposed to BDE-47 and BDE-99 was observed in region II of the midgut. Salivary glands showed acidophilic granules in the cytoplasm exposed to BDE-17 and BDE-47. The results showed that the tissues of C. sancticaroli were sensitive to flame retardants; these histopathologies can compromise the health and physiology of this organism, highlighting the concern with the presence of PBDEs in freshwater sediments.