A comparative analysis of Aedes albopictus and Aedes aegypti subjected to diapause-inducing conditions reveals conserved and divergent aspects associated with diapause, as well as novel genes associated with its onset.

Aedes albopictus and Aedes aegypti are mosquito species that are distributed worldwide and transmit diverse arboviruses of medical importance, such as those causing yellow fever, dengue, chikungunya and Zika. A. albopictus embryos may remain viable for long periods in the environment due to their ability to become dormant through quiescence or diapause, a feature that contributes to their dispersion and hinders control actions. Diapause incidence can vary among natural populations of A. albopictus, but metabolic and genetic parameters associated with its induction still need to be better defined. The present study aimed to investigate the effect of exposure to diapause-inducing conditions on several biological parameters in different populations of A. albopictus (from tropical and temperate areas) and the diapause-refractory A. aegypti (tropical and subtropical populations). As expected, only the A. albopictus populations exhibited diapause, but with a lower incidence for the population from a tropical area. Exposure to diapause-inducing conditions, however, led to a sharp reduction in fecundity for both A. albopictus and A. aegypti tropical populations, with no effect on fertility (>90%). It also led to a prolonged period as pupae for the progeny of all induced groups, with a further delay for those from temperate climates. In all those induced groups, the lipid contents in eggs and adult females were higher than in the non-induced controls, with the highest values observed for both A. albopictus groups. Three genes were selected to have their expression profile investigated: cathepsin, idgf4, and pepck. Upon exposure to diapause-inducing conditions, all three genes were upregulated in the A. albopictus embryos from the tropical region, but only idgf4 was upregulated in the temperate climate embryos. This represents a new gene associated with diapause that can be used as a target to evaluate and prevent embryonic dormancy, a possible new vector control strategy for mosquito species from temperate areas, such as A. albopictus.

The Microcephaly Epidemic Research Group Paediatric Cohort (MERG-PC): A Cohort Profile.

This cohort profile aims to describe the ongoing follow-up of children in the Microcephaly Epidemic Research Group Paediatric Cohort (MERG-PC). The profile details the context and aims of the study, study population, methodology including assessments, and key results and publications to date. The children that make up MERG-PC were born in Recife or within 120 km of the city, in Pernambuco/Brazil, the epicentre of the microcephaly epidemic. MERG-PC includes children from four groups recruited at different stages of the ZIKV microcephaly epidemic in Pernambuco, i.e., the Outpatient Group (OG/n = 195), the Microcephaly Case-Control Study (MCCS/n = 80), the MERG Pregnant Women Cohort (MERG-PWC/n = 336), and the Control Group (CG/n = 100). We developed a comprehensive array of clinical, laboratory, and imaging assessments that were undertaken by a 'task force' of clinical specialists in a single day at 3, 6, 12, 18 months of age, and annually from 24 months. Children from MCCS and CG had their baseline assessment at birth and children from the other groups, at the first evaluation by the task force. The baseline cohort includes 711 children born between February 2015 and February 2019. Children's characteristics at baseline, excluding CG, were as follows: 32.6% (184/565) had microcephaly, 47% (263/559) had at least one physical abnormality, 29.5% (160/543) had at least one neurological abnormality, and 46.2% (257/556) had at least one ophthalmological abnormality. This ongoing cohort has contributed to the understanding of the congenital Zika syndrome (CZS) spectrum. The cohort has provided descriptions of paediatric neurodevelopment and early epilepsy, including EEG patterns and treatment response, and information on the frequency and characteristics of oropharyngeal dysphagia; cryptorchidism and its surgical findings; endocrine dysfunction; and adenoid hypertrophy in children with Zika-related microcephaly. The study protocols and questionnaires were shared across Brazilian states to enable harmonization across the different studies investigating microcephaly and CZS, providing the opportunity for the Zika Brazilian Cohorts Consortium to be formed, uniting all the ZIKV clinical cohorts in Brazil.

Double BR-OVT: a new trap model for collecting eggs and adult mosquitoes from Culex quinquefasciatus and Aedes spp.

The circulation of arboviruses throughout the world and the maintenance of lymphatic filariasis endemicity in tropical countries, combined with the lack of vaccines and specific treatments, highlight the importance of reducing the populations of mosquitoes involved in the transmission of these pathogens, Aedes aegypti and Culex quinquefasciatus. To contribute to the development of new strategies for monitoring and controlling these culicids, we evaluated the performance of the Double BR-OVT trap individually and in pairs, in the field. After 18 months, the Double BR-OVT traps captured a mean of 3.5 ± 7.4 and 1.8 ± 3.2 of Culex and Aedes /residence/cycle, respectively, in addition to 410 ± 588.3 Aedes eggs/residence/cycle. When installed in pairs, the Double BR-OVT traps collected three times more adult mosquitoes of C. quinquefasciatus (9.4 ± 8.3 Culex /residence/bimester) and two times more Aedes spp. (3 ± 3.2 Aedes /residence/bimester) in comparison with the traps installed individually (2.6 ± 7.1 and 1.5 ± 3.2 Culex and Aedes /residence/bimester, respectively) (p < 0.05). The Double BR-OVT trap has an exceptional advantage: it aggregates different functionalities into a single instrument, as this type of trap can concomitantly collect eggs and adult mosquitoes of C. quinquefasciatus and A. aegypti , a feature that makes it a potentially useful tool among the strategies for monitoring and controlling these mosquitoes.

Infestation of an endemic arbovirus area by sympatric populations of Aedes aegypti and Aedes albopictus in Brazil.

BACKGROUND Aedes aegypti and Aedes albopictus are the most important arbovirus vectors in the world. OBJECTIVES This study aimed to investigate and compare the infestation pattern of these species in a neighbourhood of Recife, Brazil, endemic for arboviruses in 2005 (T1) and 2013 (T2). METHODS Infestation, distribution and relative abundance of these sympatric species were recorded by egg collection using a network of 59 sentinel ovitraps (s-ovt) at fixed sampling stations for 12 months in T1 and T2. FINDINGS A permanent occupation pattern was detected which was characterised by the presence of egg-laying females of one or both species with a high ovitrap positivity index (94.3 to 100%) throughout both years analysed. In terms of abundance, the total of eggs collected was lower (p < 0.005) in T2 (146,153) than in T1 (281,103), although ovitraps still displayed a high index of positivity. The spatial distribution showed the presence of both species in 65.1% of the 148 s-ovt assessed, while a smaller number of traps exclusively contained Ae. aegypti (22%) or Ae. albopictus (13.2%) eggs. MAIN CONCLUSIONS Our comparative analysis demonstrated the robustness of the spatial occupation and permanence of Ae. aegypti and Ae. albopictus populations in this endemic urban area.

Field evaluation of sticky BR-OVT traps to collect culicids eggs and adult mosquitoes inside houses.

INTRODUCTION: Culex quinquefasciatus is a mosquito of importance to public health, as it represents a real and/or potential risk for the transmission of pathogens to humans, such as some arthropod-borne viruses and nematodes that cause filariasis. In Brazil, three municipalities in the Metropolitan Region of Recife (RMR) that are endemic for lymphatic filariasis conducted control actions targeting this vector. With the goal of contributing novel C. quinquefasciatus collection strategies, a sticky trap capable of collecting eggs and imprisoning mosquitoes was investigated. METHODS: To evaluate the performance of the sticky BR-OVT trap, tests were carried out in the neighborhoods of Caixa d'Água and Passarinho (Olinda-PE-Brasil) between August 2011 and June 2012. Sixty traps were installed in the indoor areas of residences in the two districts. RESULTS: During the 11-month study, 0.52 [standard deviation (SD) = 1.52] Culex egg rafts, 2.16 (SD = 4.78) C. quinquefasciatus/trap/month, and 0.55 (SD = 1.28) Aedes/trap/month were caught. Female specimens predominated the traps (59% of C. quinquefasciatus and 96% of Aedes spp.). CONCLUSIONS: The results demonstrated that the sticky BR-OVT trap is a useful tool for the collection of adult culicids of medical importance and offers an innovative way to collect C. quinquefasciatus eggs and adults in a single trap.

Field evaluation of sticky BR-OVT traps to collect culicids eggs and adult mosquitoes inside houses

Abstract INTRODUCTION: Culex quinquefasciatus is a mosquito of importance to public health, as it represents a real and/or potential risk for the transmission of pathogens to humans, such as some arthropod-borne viruses and nematodes that cause filariasis. In Brazil, three municipalities in the Metropolitan Region of Recife (RMR) that are endemic for lymphatic filariasis conducted control actions targeting this vector. With the goal of contributing novel C. quinquefasciatus collection strategies, a sticky trap capable of collecting eggs and imprisoning mosquitoes was investigated. METHODS: To evaluate the performance of the sticky BR-OVT trap, tests were carried out in the neighborhoods of Caixa d'Água and Passarinho (Olinda-PE-Brasil) between August 2011 and June 2012. Sixty traps were installed in the indoor areas of residences in the two districts. RESULTS: During the 11-month study, 0.52 [standard deviation (SD) = 1.52] Culex egg rafts, 2.16 (SD = 4.78) C. quinquefasciatus/trap/month, and 0.55 (SD = 1.28) Aedes/trap/month were caught. Female specimens predominated the traps (59% of C. quinquefasciatus and 96% of Aedes spp.). CONCLUSIONS The results demonstrated that the sticky BR-OVT trap is a useful tool for the collection of adult culicids of medical importance and offers an innovative way to collect C. quinquefasciatus eggs and adults in a single trap.