First official record of Aedes (Stegomyia) albopictus (Diptera: Culicidae) in the Acre State, Northern Brazil.

Aedes (Stegomyia) albopictus (Skuse, 1854) was reported in Brazil for the first time in 1986 and has shown marked expansion throughout the Brazilian territory. During a routine activity to control dengue fever conducted by the Division of Entomology of the Municipal Health Department in Rio Branco city, adults and immatures of Culicidae were collected in a peri-urban area. The identified Culicidae forms indicated that they belonged to the species Ae. albopictus. This is the first official record of the presence of Ae. albopictus in the Acre State, confirming its current presence in all Brazilian states.

Aedes aegypti in Southern Brazil: Spatiotemporal Distribution Dynamics and Association with Climate and Environmental Factors.

In Brazil, the mosquito Aedes (Stegomyia) aegypti is considered the main vector of the dengue, chikungunya, and Zika arbovirus transmission. Recent epidemiological studies in southern Brazil have shown an increase in the incidence of dengue, raising concerns over epidemiological control, monitoring, and surveys. Therefore, this study aimed at performing a historical spatiotemporal analysis of the Ae. aegypti house indices (HI) in southern Brazil over the last 19 years. As vector infestation was associated with climatic and environmental variables, HI data from the Brazilian Ministry of Health, climate data from the Giovanni web-based application, and environmental data from the Mapbiomas project were used in this study. Our results showed an expressive increase in the number of HI surveys in the municipalities confirming the vector presence, as compared to those in 2017. Environmental variables, such as urban infrastructure, precipitation, temperature, and humidity, were positively correlated with the Ae. aegypti HI. This was the first study to analyze Ae. aegypti HI surveys in municipalities of southern Brazil, and our findings could help in developing and planning disease control strategies to improve public health.

First official record of Aedes (Stegomyia) albopictus (Diptera: Culicidae) in the Acre State, Northern Brazil

ABSTRACT Aedes (Stegomyia) albopictus (Skuse, 1854) was reported in Brazil for the first time in 1986 and has shown marked expansion throughout the Brazilian territory. During a routine activity to control dengue fever conducted by the Division of Entomology of the Municipal Health Department in Rio Branco city, adults and immatures of Culicidae were collected in a peri-urban area. The identified Culicidae forms indicated that they belonged to the species Ae. albopictus. This is the first official record of the presence of Ae. albopictus in the Acre State, confirming its current presence in all Brazilian states.

Increased Repellent Effect of DEET on Aedes aegypti (Diptera: Culicidae) Field Population.

Insecticides and repellents are routinely used in Brazil because of the high rates of arbovirus transmission and the nuisance caused by mosquitoes. However, few studies have assessed the effectiveness of repellents against mosquito populations that have been under exposure to xenobiotics, mainly insecticides and repellents. This study investigated the sensitivity of a field population of Aedes aegypti (Linnaeus, 1762) from a dengue-endemic area under high insecticide pressure to N,N-diethylmethylbenzamide (DEET), the active ingredient in common repellent products. The field (Laranjeiras, Sergipe, Brazil) and laboratory (Rockefeller) populations were characterized for the presence of the Val1016Ile kdr mutation, associated with pyrethroid resistance, and locomotor activity. Repellency bioassays were performed to assess the response of the mosquitoes to human odor by exposing them to 10% DEET applied to the skin in ethanol. Samples from the field population showed higher frequency of the kdr mutation, 21.9% homozygous and 21.9% heterozygous, greater locomotor activity and greater sensitivity to DEET than the laboratory population. These results suggest increased sensitivity to DEET in field populations and a possible interaction between insecticide exposure and sensitivity to DEET.

Body size does not affect locomotor activity of Aedes aegypti and Aedes albopictus females (Diptera:Culicidae).

Intraspecific competition between mosquito larvae can affect several adult traits, particularly size. This study tested the hypothesis that intraspecific competition during the larval stage affects wing length in Ae. aegypti and Ae. albopictus adults, in turn influencing locomotor activity. L1 larvae of both species were reared in trays under conditions of low and high competition. After adults had emerged, the locomotor activity of virgin females of Ae. aegypti and Ae. albopictus was evaluated under light-dark cycles of 12:12 h at 25 °C and 70% relative humidity. At the end of the locomotor activity experiment, the left wings of the mosquitoes were removed to be measured, and wing length was used as an indicator of adult female size. Although the results showed that the wing lengths of Ae. aegypti and Ae. albopictus females reared under low larval competition were significantly greater than those of females reared under high larval competition, this difference did not affect locomotor activity in females of either species, demonstrating that locomotor activity in small Ae. aegypti and Ae. albopictus females is not lower than in larger females. Our findings reinforce the idea that intraspecific competition alters the wing length of Ae. aegypti and Ae. albopictus females and provide new evidence about this effect on the locomotor activity of these species.

Locomotor activity in Aedes aegypti with different insecticide resistance profiles.

OBJECTIVE: To evaluate locomotor activity in four field populations of Ae. aegypti with different insecticide resistance profiles from the state of São Paulo for two years. METHODS: This study comprised the susceptible Rockefeller strain and four populations from São Paulo, Brazil: two considered populations with "reduced susceptibility" to pyrethroids (Campinas and Marília), and two "resistant populations" (Santos and Ribeirão Preto). First, 2016 and 2017 eggs from these five populations were hatched in laboratory. Virgin females underwent experiments under laboratory conditions at 25°C, with 12:12h light/dark (LD) photoperiod; 24-hour individual activity was recorded using a locomotor activity monitor (LAM). RESULTS: In females from 2016 field populations, both resistant populations showed significant more locomotor activity than the two reduced susceptibility populations and the Rockefeller strain (p < 0.05). As for females from 2017 field populations, reduced susceptibility populations showed a significant increased locomotor activity than the Rockefeller strain, but no significant difference when compared to Santos resistant population (p > 0.05). CONCLUSIONS: Our results indicate that insecticide-resistant Ae. aegypti populations show increased locomotor activity, which may affect the transmission dynamics of their arboviruses.

Interspecific Mating Effects on Locomotor Activity Rhythms and Refractoriness of Aedes albopictus (Diptera: Culicidae) Females.

This study tests the hypotheses that the locomotor activity of Ae. albopictus females is not significantly altered by the presence of accessory gland (AG) extracts from conspecific and heterospecific males, and that Ae. albopictus females remain receptive to mating with conspecific males even after receiving AG of Ae. aegypti males. Virgin Ae. albopictus females were injected with saline (control group), AG extracts of Ae. aegypti males (aegMAG) or AG extracts of Ae. albopictus males (albMAG). Locomotor activity was evaluated under 12 h of light and 12 h of darkness at 25 °C. All live Ae. albopictus females were subsequently exposed to conspecific males for 48 h, and their spermathecae were dissected for the presence of sperm. Females injected with aegMAG and albMAG showed significant decreases in total, diurnal and diurnal without lights-on Period activities. Females injected with aegMAG showed significant decreases in nocturnal and nocturnal without lights-off period activities. Females injected with albMAG showed significant decreases in lights-off activity. A total of 83% of Ae. albopictus females injected with aegMAG and 10% of females injected with albMAG were inseminated by conspecific males. These results, coupled with our previous paper on MAG and interspecific mating effects on female Ae. aegypti, demonstrate contrasting outcomes on locomotor activities and loss of sexual receptivity, both conspecific and heterospecific MAGs capable of sterilizing virgin Ae. aegypti, but only conspecific MAGs sterilizing Ae. albopictus, whereas locomotor activities were depressed in females of both species after heterospecific and conspecific injections or treatments.

Silent circulation of dengue virus in Aedes albopictus (Diptera: Culicidae) resulting from natural vertical transmission.

Vertical transmission in Aedes aegypti and Aedes albopictus is considered a maintenance mechanism for dengue virus (DENV) during unfavorable conditions and may be implicated in dengue outbreaks. Since DENV infection dynamics vary among wild-type viruses and vector populations, vertical transmission rates can also vary between regions. However, even though São Paulo is the most populous city in the Americas and has experienced major dengue epidemics, natural vertical transmission had never been detected in this area before. Here we confirm and describe for the first time natural vertical transmission of DENV-3 in two pools of male Ae. albopictus from the city of São Paulo. The detection of DENV-3 in years when no human autochthonous cases of this serotype were recorded suggests that silent circulation of DENV-3 is occurring and indicates that green areas may be maintaining serotypes that are not circulating in the human population, possibly by a vertical transmission mechanism.

The Asian tiger mosquito in Brazil: Observations on biology and ecological interactions since its first detection in 1986.

Aedes (Stegomyia) albopictus is a mosquito originating from the Asian continent, which was detected in the Americas in 1985 and Brazil in 1986. Due to its rapid expansion throughout Brazil, this species has already been reported in 26 of the 27 federative units of Brazil. In this review, we evaluate some of the biological, epidemiological and ecological characteristics of Ae. albopictus through critical analysis of their importance in the pathogen transmission dynamics, since its first record in the country. We show that immature forms of this species are frequently found in artificial breeding sites whereas females exhibit anthropophilic behavior despite its eclecticism on blood feeding. In addition, Ae. albopictus shows advantages in interspecific competition with Ae. aegypti for both immature and adult stages. Taking together, these aspects as well as its vector competence indicate that Ae. albopictus could act as a bridge vector between sylvatic and urban pathogen transmission cycles. We conclude by pointing to the need of continuous surveillance of Ae. albopictus in Brazil and raise several questions that still need to be answered.

Gonotrophic discordance in Culex quinquefasciatus (Diptera: Culicidae) in the city of São Paulo, Brazil

Abstract INTRODUCTION: This study aimed to assess the occurrence of gonotrophic discordance in females of Culex quinquefasciatus in São Paulo, Brazil. METHODS: Resting females were collected monthly for 8 months. Females of Cx. quinquefasciatus were identified, and their midgut and ovaries were dissected. RESULTS: Two hundred females were dissected, out of which, 27.5% were nulliparous and 57% were parous. Most females had no blood in the midgut, but gonotrophic discordance was found in 21% females. CONCLUSIONS: Females of Cx. quinquefasciatus showed a high parity rate and gonotrophic discordance, which could favor the vector capacity of this species.

Gonotrophic discordance in Culex quinquefasciatus (Diptera: Culicidae) in the city of São Paulo, Brazil.

INTRODUCTION: This study aimed to assess the occurrence of gonotrophic discordance in females of Culex quinquefasciatus in São Paulo, Brazil. METHODS: Resting females were collected monthly for 8 months. Females of Cx. quinquefasciatus were identified, and their midgut and ovaries were dissected. RESULTS: Two hundred females were dissected, out of which, 27.5% were nulliparous and 57% were parous. Most females had no blood in the midgut, but gonotrophic discordance was found in 21% females. CONCLUSIONS: Females of Cx. quinquefasciatus showed a high parity rate and gonotrophic discordance, which could favor the vector capacity of this species.

Parity and gonotrophic discordance of females of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in the city of São Paulo, SP, Brazil.

The objective of this study was to assess the parity, presence of blood in the stomach, and the gonotrophic discordance of females of Aedes aegypti and Aedes albopictus captured in two areas of the city of São Paulo. The captures were undertaken monthly, by aspiration, in the period from January, 2015 to August, 2017. All the females of the two species had their midguts and ovaries dissected to determine the presence of blood and the parity/stage of maturation. With regard to parity, 27% and 34% of the females of Ae. aegypti and Ae. albopictus, respectively, were parous or were in advanced stages of the development of their ovaries (33% and 27%, respectively). The larger part of the females of Ae. aegypti and Ae. albopictus contained blood in their stomachs (77% and 60%, respectively), beyond which 36% and 27% of the females of Ae. aegypti and Ae. albopictus, respectively, were in gonotrophic discordance. Our results indicate favorable conditions in the study areas because of the presence of parous females. Moreover, this frequent and multiple contact of Ae. aegypti and Ae. albopictus females with vertebrate hosts, such as humans, increases the possibility of transmitting the viruses they may be carrying.

Seasonal and spatial distribution of Aedes aegypti and Aedes albopictus in a municipal urban park in São Paulo, SP, Brazil.

Dengue, yellow fever, chikungunya and Zika are important arboviruses present in various countries of the world, the etiological agents of which are transmitted to human-beings by the bite of infected females of Aedes aegypti and Aedes albopictus. Biological aspects of these vectors, such as their distribution and abundance, are influenced by climatic variables such as rainfall and temperature. We assess the spatial and seasonal distribution of Ae. aegypti and Ae. albopictus, during spring 2014 and spring 2015 and autumn 2015 and autumn 2016, in an urban Municipal Park, São Paulo (SP, Brazil), using 36 ovitraps. The Park was divided into three areas: internal, intermediate and peripheral, and 12 geo-referenced ovitraps were randomly installed in each area. We evaluated the association between the environmental variables maximum and minimum temperatures and rainfall with oviposition rates in the park using negative binomial regression models. Further, to estimate the distribution of the species in the three areas during the seasons, we employed the geostatic interpolation method with the use of kriging. Our results show the presence of the two species in the area in both the seasons but with a greater predominance of Ae. albopictus. Both species were significantly more abundant in spring than autumn. However, our results suggested that this seasonal variation was mediated by the maximum and minimum temperatures, which were significantly associated with the oviposition rate of both species, in all regression models. Cumulative rainfall of the week of collection was not associated with the abundance of the vectors in the multiple models. Moreover, regardless of climatic variables, the oviposition of Ae. aegypti was positively associated with the peripheral area of the park compared with the internal area (oviposition rate ratio [ORR]: 4.92; 95% CI: 2.46-9.83). On the other hand, the oviposition of Ae. albopictus was negatively associated with the peripheral area as compared with the internal one (ORR: 0.59; 95% CI: 0.38-0.91). The spatial distribution revealed a pattern of spatial segregation, confirming the ecological preferences of each species. Green areas in urban centers can serve as important habitats for various mosquito species, including especially Ae. albopictus. Thus it is that our study highlights the importance of maintaining surveillance for the targeting of control strategies in green areas as well, since most control strategies are focused on Ae. aegypti and urban residential centers.

Natural vertical transmission of dengue virus in Aedes aegypti and Aedes albopictus: a systematic review.

Dengue is of great concern in various parts of the world, especially in tropical and subtropical countries where the mosquito vectors Aedes aegypti and Aedes albopictus are present. The transmission of this virus to humans, by what is known as horizontal transmission, occurs through the bite of infected females of one or other of the two mosquito species. Furthermore, an infected female or male parent, by what is known as vertical transmission, can transfer this arbovirus to some part of their offspring. Considering that vertical transmission may represent an important strategy for maintaining the circulation of arboviruses in nature, the verification of this phenomenon worldwide is extremely important and necessary to better understand its dynamic. In the present study, we conducted a literature review of the presence of natural vertical transmission of dengue virus in Ae. aegypti and Ae. albopictus worldwide. Searches were conducted in MEDLINE, sciELO and Lilacs and all the studies published in Portuguese, English and Spanish were read, evaluated and organized by mosquito species, serotype and the location at which the samples were collected. Forty-two studies were included in accordance with the exclusion criteria and methodology. The presence of natural vertical transmission in Ae. aegypti and Ae. albopictus was most clearly evidenced by dengue virus in endemic countries, especially in those in South America and Asia. Despite several African countries being considered endemic for dengue, there is a lack of publications on this subject on that continent, which highlights the importance of conducting studies there. Furthermore, the finding of natural vertical transmission in Ae. albopictus in countries where this species is not yet incriminated as a vector is of great concern as it demonstrates the circulation of this virus in populations of Ae. albopictus and alerts to the possibility of some other mosquito species playing a role in the transmission dynamics of this arbovirus. Parallel to this, the small number of studies of natural vertical transmission of chikungunya and Zika virus in the world may be explained by the recent entry of these arboviruses into most of the countries concerned.

Aedes aegypti breeding site in an underground rainwater reservoir: a warning.

We describe the discovery of Aedes aegypti underground breeding site in the Pinheiros neighborhood of São Paulo, SP, during an entomological survey program performed in 2016. Even with intense surveillance and vector control, large numbers of mosquitoes were present in this area. A detailed investigation allowed for the detection of Ae. aegypti in an underground reservoir used for rainwater storage. After the implementation of protection screens in the accesses, the presence of the vector was no longer detected. In this study, we discuss the frequent use of this type of reservoir structure and its risk for mosquito production.

Aedes aegypti breeding site in an underground rainwater reservoir: a warning / Criadouro de Aedes aegypti em reservatório subterrâneo de água da chuva: um alerta

ABSTRACT We describe the discovery of Aedes aegypti underground breeding site in the Pinheiros neighborhood of São Paulo, SP, during an entomological survey program performed in 2016. Even with intense surveillance and vector control, large numbers of mosquitoes were present in this area. A detailed investigation allowed for the detection of Ae. aegypti in an underground reservoir used for rainwater storage. After the implementation of protection screens in the accesses, the presence of the vector was no longer detected. In this study, we discuss the frequent use of this type of reservoir structure and its risk for mosquito production.

RESUMO Descreve-se o encontro de criadouro subterrâneo de Aedes aegypti no bairro de Pinheiros, São Paulo, SP, ocorrido durante um programa de levantamento entomológico, realizado em 2016. Mesmo com intensa vigilância e controle vetorial, grande quantidade de mosquitos estava presente nessa área. Investigação minuciosa permitiu a detecção de Ae. aegypti em reservatório subterrâneo para armazenamento de água pluvial. Após a implantação de telas de proteção nos acessos, não foi mais detectada a presença do vetor. O uso frequente desse tipo de estrutura e o seu risco para a produção de mosquitos é discutido.

Emerging arboviruses and public health challenges in Brazil.

Environmental modification by anthropogenic actions, disordered urban growth, globalization of international exchange and climate change are some factors that help the emergence and dissemination of human infectious diseases transmitted by vectors. This review discusses the recent entry of three arboviruses in Brazil: Chikungunya, West Nile, and Zika virus, focusing on the challenges for the Country's public health. The Brazilian population is exposed to infections caused by these three arboviruses widely distributed on the national territory and associated with humans. Without effective vaccine and specific treatment, the maintainance and integration of a continuos entomological and epidemiological surveillance are important so we can set methods to control and prevent these arboviruses in the Country. RESUMO A modificação do ambiente por ações antrópicas, o crescimento urbano desordenado, o processo de globalização do intercâmbio internacional e as mudanças climáticas são alguns fatores que vêm facilitando a emergência e disseminação de doenças infecciosas humanas transmitidas por vetores. Este comentário aborda a recente entrada de três arbovírus no Brasil, Chikungunya (CHIKV), West Nile (WNV) e Zika (ZIKV), com enfoque nos desafios para a Saúde Pública do País. Transmitidos por mosquitos vetores amplamente distribuídos no território nacional e associados ao homem, a população brasileira encontra-se exposta à infecção por esses três arbovírus. Na ausência de vacina eficaz e tratamento específico, são importantes a manutenção e integração de uma vigilância entomológica e epidemiológica contínua, a fim de direcionarmos métodos de controle e prevenção contra essas arboviroses no País.

Finding Aedes aegypti in a natural breeding site in an urban zone, Sao Paulo, Southeastern Brazil.

This is the description of how nine Aedes aegypti larvae were found in a natural breeding site in the Pinheiros neighborhood, city of Sao Paulo, SP, Southeastern Brazil. The record was conducted in December 2014, during an entomological surveillance program of dengue virus vectors, with an active search of potential breeding sites, either artificial or natural. FindingAe. aegypti larvae in a tree hole shows this species' ability to use both artificial and natural environments as breeding sites and habitats, which points towards the importance of maintaining continuous surveillance on this mosquito in all kinds of water-holding containers.

Emerging arboviruses and public health challenges in Brazil / Arboviroses emergentes e novos desafios para a saúde pública no Brasil

ABSTRACT Environmental modification by anthropogenic actions, disordered urban growth, globalization of international exchange and climate change are some factors that help the emergence and dissemination of human infectious diseases transmitted by vectors. This review discusses the recent entry of three arboviruses in Brazil: Chikungunya, West Nile, and Zika virus, focusing on the challenges for the Country's public health. The Brazilian population is exposed to infections caused by these three arboviruses widely distributed on the national territory and associated with humans. Without effective vaccine and specific treatment, the maintainance and integration of a continuos entomological and epidemiological surveillance are important so we can set methods to control and prevent these arboviruses in the Country.

RESUMO A modificação do ambiente por ações antrópicas, o crescimento urbano desordenado, o processo de globalização do intercâmbio internacional e as mudanças climáticas são alguns fatores que vêm facilitando a emergência e disseminação de doenças infecciosas humanas transmitidas por vetores. Este comentário aborda a recente entrada de três arbovírus no Brasil, Chikungunya (CHIKV), West Nile (WNV) e Zika (ZIKV), com enfoque nos desafios para a Saúde Pública do País. Transmitidos por mosquitos vetores amplamente distribuídos no território nacional e associados ao homem, a população brasileira encontra-se exposta à infecção por esses três arbovírus. Na ausência de vacina eficaz e tratamento específico, são importantes a manutenção e integração de uma vigilância entomológica e epidemiológica contínua, a fim de direcionarmos métodos de controle e prevenção contra essas arboviroses no País.

Twenty-eight years of Aedes albopictus in Brazil: a rationale to maintain active entomological and epidemiological surveillance.

INTRODUCTION: Aedes albopictus was first detected in Brazil in 1986. This mosquito species presents a major threat to public health because Brazilian populations have shown substantial vector competence for arboviruses such as dengue and chikungunya. METHODS: We updated the records of Ae. albopictus in several States of Brazil, focusing on areas in which its presence had been reported after 2002. RESULTS: Twenty-eight years after its arrival in Brazil, Ae. albopictus has been detected in 24 of 27 States. CONCLUSIONS: The rapid spread of this species and its high vector competence demonstrate the danger of Ae. albopictus in Brazil.