Diversidad, riqueza de especies y abundancia relativa de mosquitos adultos (Diptera: Culicidae) en localidades del municipio Gran Sabana, edo. Bolívar / Diversity, species richness and relative abundance of adult mosquitoes (Diptera: Culicidae) in localities of the Gran Sabana municipality, Bolívar state

Este estudio forma parte de la primera etapa de una serie de estudios sobre la ecología, biodiversidad y biogeografía de los mosquitos de la familia Culicidae de Venezuela, principalmente en Bolívar y Delta Amacuro. El objetivo del estudio fue caracterizar la composición de especies, la abundancia y la biodiversidad de mosquitos (Diptera; Culicidae) en el municipio Gran Sabana del estado Bolívar. Las capturas de mosquitos adultos se realizaron con aspiradores bucales mediante capturas por atracción al cebo humano y con trampas de luz negra. Se determinó la riqueza de especies, su abundancia relativa e índices ecológicos de diversidad Shannon-Wiener (H'), equidad de Simpson (E) y dominancia-D, del área general de estudio y sitios o comunidades de muestreo. Los resultados del estudio, generaron el registro de 7.860 ejemplares adultos de Culicidae identificados a nivel de especie, pertenecientes a 69 especies y 17 géneros, de ellos 7.797 (99,19%) fueron hembras adultas capturadas picando o con trampas de luz y 63 (0,81%) fueron machos capturados con trampas de luz. El 16,6% (1.297) de las hembras fue atraído por trampas de luz y el 83,4% (6.500) por cebo humano. Entre las especies más abundantes del estudio están: Culex quinquefasciatus (26,67 %), Anopheles peryassui (12,32 %), Aedes aegypti (11,87 %), Coquilletidia juxtamansonia (8,28 %), Anopheles braziliensis (6,97 %) Anopheles triannulatus s.l. (6,39 %), Coquilletidia nigricans (2,88 %), Coquilletidia venezuelensis (2,51 %) y Anopheles albitarsis s.l. (2,44 %), las cuales en conjunto representan 80,33 % del total de adultos capturado. Se discuten algunos aspectos sobre su ecología, importancia médica y el riesgo epidemiológico que representan para el país algunas especies reportadas. La diversidad de Shannon-Wiener (H') del área general de estudio fue de 2,665, la equidad de Simpson (E) fue igual a 0,8787222 y la dominancia (D) fue de 0,1213. El mayor índice de diversidad (Shannon-Wiener) ocurrió en Chiririka (2,675), seguido de Betania (2,409), Santa Elena Capital (2,354), Manak-Krü (2,203) y Waramasén (2,181). En cuanto a la riqueza de especies por localidad, las comunidades con mayor riqueza de especies fueron: Santa Elena (Capital), Waramasén y Chiririka con 50, 35 y 30 especies respectivamente, seguidas por San Antonio del Morichal con 23 y Kinok-Pon Parú, con 22 especies(AU)

This is the first part of a series of studies related to biodiversity, ecological and biogeographic aspects of the mosquitoes of Culicidae family in Venezuela. The objective of this study was the ecological characterization of species composition, diversity and abundance of Culicidae mosquitoes (Diptera: Culicidae) in the Gran Sabana Municipality, Bolívar State. Mosquitoes were captured in adult collections, with aspirators on human landing catches and with black light traps. A total of 7.860 adult's mosquitoes were collected and 69 species and 17 genera of Culicidae were identified. A total of 7.797 mosquitoes (99.19%) were females and 63 (0,81%) were males. Some 16,6 % (1.297) of females mosquitoes were attracted to the light traps and 83,4% (6.500) to human bait. The most abundant species in adult stage were: Culex quinquefasciatus (26,67%), Anopheles peryassui (12,32 %), Aedes aegypti (11,87 %), Coquilletidia juxtamansonia (8,28%), Anopheles braziliensis (6,97%), Anopheles triannulatus s.l. (6,39%), Coquilletidia nigricans (2,88%), Coquilletidia venezuelensis (2,51%) and Anopheles albitarsis s.l. (2,44%). Their medical importance of some mosquito species is commented, and some ecological and epidemiological aspects of the mosquito reported are discussed. The diversity index (Shannon-Wiener) of the estudy area was 2,665, the Simpson equity index was 0, 8787222 and the index of dominance was 0, 1213. The higher diversity index was registered in Chiririka (2,675), Betania (2,409), Santa Elena Capital (2,354), Manak-Krü (2,203) and Waramasén (2,181). The higher species richness was registered in Santa Elena (50 species), Waramasén (35 species), Chiririka (30 species), San Antonio del Morichal (23 species) and Kinok-Pon Parú (22 species) (AU)

Importance of microenvironment to arbovirus vector distribution in an urban area, São Paulo, Brazil

Abstract INTRODUCTION: The study of the landscape ecology, biological microhabitat, and epidemiological implications for the distribution of the main vectors Aedes aegypti and Aedes albopictus contribute to the prevention and control actions regarding the diseases they transmit. METHODS: This study sought to assess data on positive properties of the vector control program activities from 1998 to 2010. An entomological survey was also carried out on a sample of buildings collecting larvae and pupae from containers between October and April (spring / summer) from 2002 to 2005. We assessed the physico-chemical data of the water in 20% of positive containers. The vegetation and urbanization were assessed with the aid of satellite images and microenvironments were classified as urbanized, woods, and shrubs. The data were analyzed using statistical and geoprocessing software. RESULTS: Ae. aegypti and Ae. albopictus colonized all types of microhabitats and microenvironments, predominantly in the urbanized area, in isolation and in coexistence. The microhabitat of Ae. aegypti showed a temperature gradient greater than that of Ae. albopictus, and there was an association with urbanized areas for the first species and wooded areas for the last species. CONCLUSIONS: Landscape ecology and intra-urban differences favor different microclimates, which contribute to the coexistence of species in the urban environment in an area close to the forest, raising the risk of other arbovirus infections in urban areas. The ecological niche should be considered for Ae. albopictus. Entomological and virologic monitoring are suggested as arbovirus surveillance actions in urban infested centers near preserved forests.

Increased capture of Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae) by removing one ADULTRAP component

Abstract INTRODUCTION: Aedes aegypti is the main vector responsible for the transmission of numerous arboviruses. Adultrap® has been developed to catch these insects. METHODS: We tested the effectiveness of capturing adults with and without one of the components of Adultrap®. RESULTS: The mean number of insects caught by the original trap was 1.25 (standard deviation = 1.28), while the average obtained with the modified trap was 8.88 (standard deviation = 3.44). The medians were statistically different (p = 0.001) according to the Mann-Whitney test. CONCLUSIONS: The modification of Adultrap® increased the average catch of Ae. aegypti by up to seven times.

The austral-most record of the genus Haemagogus Williston (Diptera: Culicidae)

Abstract INTRODUCTION: The genus Haemagogus Williston is restricted to Central America and North and middle of South America and it includes numerous species of yellow fever virus vectors. METHODS: Adult female and larvae mosquitoes were collected using hand aspirators and dipper and pipette, respectively. RESULTS: The first record of a species of Haemagogus and particularly of Haemagogus spegazzinii was from La Pampa, Argentina. With this registry, the number of species found in La Pampa province rises to 18. CONCLUSIONS: New information on breeding sites for the species and implications of this new record suggest a possible extension of distribution in the near future.

Chemical composition and larvicidal activities of essential oil of Cinnamomum camphora (L. ) leaf against Anopheles stephensi

Abstract INTRODUCTION Anopheles stephensi is the main malaria vector in Southeast Asia. Recently, plant-sourced larvicides are attracting great interests. METHODS: The essential oil was extracted from the leaf of Cinnamomum camphora (L.), and a bioassay was conducted to determine the larvicidal efficacy. The chemical composition of the essential oil was determined by GC-MS analysis. RESULTS: The oil showed strong, dose-dependent larvicidal activities. The onset of larvicidal efficiency was rapid. The LC50 and LC95 were determined as 0.146% and 1.057% at 1 h, 0.031% and 0.237% at 12 h, 0.026% and 0.128% at 24 h, respectively. The oil contains 32 compounds. CONCLUSIONS The essential oil of C. camphora leaf has an excellent larvicidal potential for the control of A. stephensi.

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.

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.

Aedes aegypti spreading in South America: new coldest and southernmost records

The geographic distribution of Aedes (Stegomyia) aegypti (L.) in South America has been expanding during the last decades. Herein we present two new distribution records that extend its southern limits towards localities with extremer environmental conditions than reported to date. San Antonio Oeste constitutes the southernmost finding for the continent (40º44'S), whereas Tandil is the infested locality with the coldest mean annual temperature in Argentina (14.17ºC). The projection of a previous distribution model for Ae. aegypti predicts these two cities as positive and suggests several other localities with suitable conditions for vector proliferation beyond its assumed distribution limits.

Novel molecular evidence of population structure in Anopheles (Kerteszia) bellator from Brazilian Atlantic Forest

Anopheles bellator is a primary malaria vector in the Atlantic Forest. Partial sequences of timeless and Clock genes were used to assess the genetic differentiation of five Brazilian populations, which showed strong population structure (e.g. high F ST values and fixed differences) in all pairwise comparisons between Bahia sample and the others from Paraná, São Paulo and Rio de Janeiro states. Also, the resulting phylogenetic trees clearly grouped the sequences from Bahia in a different cluster with high bootstrap values. Among southern and southeastern populations low levels of genetic differentiation were found suggesting a general stability of the genetic structure.

New record and extended geographical distribution of Aedes fluviatilis (Lutz, 1904) in Ceará, northeastern Brazil

Abstract INTRODUCTION Aedes fluviatilis(Lutz, 1904) is considered a potential vector of yellow fever and dengue viruses and is naturally infected by Wolbachia. METHODS In March 2018, during a field activity in the municipality of Saboeiro, 163 mosquito larvae were collected in a dammed area of the Jaguaribe River. RESULTS Of the larvae collected, 143 (87.7%) were identified asAe. fluviatilis. CONCLUSIONS We report the first documentation of Ae. fluviatilis in the municipality of Saboeiro, northeastern Brazil. It is important to conduct additional entomological surveys to characterize the local Culicidae fauna. Ignoring the presence and dispersion of this vector could be a public health risk.

A populational-based birth cohort study in a low-income urban area in Rio de Janeiro, Brazil: implementation and description of the characteristics of the study / Um estudo de coorte de nascimento de base populacional em uma área urbana desfavorecida no Rio de Janeiro, Brasil: implementação e descrição das características do estudo / Estudio de una cohorte de nacimientos de base poblacional en un área urbana desfavorecida de Río de Janeiro, Brasil: implementación y descripción de las características del estudio

Abstract: A comprehensive cohort study including an entomological surveillance component can contribute to our knowledge of clinical aspects and transmission patterns of arbovirosis. This article describes the implementation of a populational-based birth cohort study that included an entomological surveillance component, and its associated challenges in a low-income community of Rio de Janeiro, Brazil. The participants were recruited in two periods: from 2012 to 2014, and from 2015 to 2017. The children had scheduled pediatric consultations and in case of fever. Epidemiological, clinical data and biological samples were collected at pediatric visits. Active febrile surveillance was performed by telephone calls, social networking, message apps, and household visits. A total of 387 newborns and 332 new children were included during the first and second recruitment periods, respectively. By July 2017, there were 451 children on follow-up. During the study, 2,759 pediatric visits were performed: 1,783 asymptomatic and 976 febrile/rash consultations. The number of febrile or rash consultations increased 3.5-fold after the use of media tools for surveillance. No temporal pattern, seasonality or peak of febrile cases was observed during the study period. A total of 10,105 adult mosquitoes (including 3,523 Aedes spp. and 6,582 Culex quinquefasciatus) and 46,047 Aedes eggs were collected from households, schools, and key sites. Although challenging, this structured sentinel populational-based birth cohort is relevant to the knowledge of risks and awareness of emerging pathogens.

Resumo: Estudos de coorte com um componente de vigilância epidemiológica podem contribuir para nosso conhecimento dos aspectos clínicos e dos padrões de transmissão de arboviroses. Este artigo descreve a implementação de um estudo de coorte de nascimento de base populacional que incluiu um componente de vigilância entomológica e desafios relacionados numa comunidade desfavorecida do Rio de Janeiro, Brasil. Os participantes foram recrutados em dois períodos: de 2012-2014 e de 2015-2017. As crianças tiveram consultas pediátricas agendadas e em caso de febre. Dados epidemiológicos, clínicos e amostras biológicas foram coletadas nas visitas pediátricas. A vigilância ativa febril foi realizada por meio de ligações telefônicas, redes sociais, aplicativos de mensagens e visitas domiciliares. Um total de 387 recém-nascidos e 332 novas crianças foram incluídas durante o primeiro e segundo períodos de recrutamento, respectivamente. Em Julho de 2017, havia 451 crianças em seguimento. Durante o estudo, foram realizadas 2.759 visitas pediátricas: 1.783 assintomáticas e 976 consultas por febre/exantema. O número de consultas por febre ou exantema aumentou 3,5 vezes após uso de ferramentas de mídia para vigilância. Nenhum padrão temporal, sazonalidade ou pico de casos de febre foi observado durante o período do estudo. Um total de 10.105 mosquitos adultos (incluindo 3.523 Aedes spp. e 6.582 Culex quinquefasciatus) e 46.047 ovos foram coletados de domicílios, escolas, e pontos estratégicos. Apesar dos desafios, esta coorte de nascimento sentinela de base populacional é relevante para o conhecimento dos riscos e de patógenos emergentes.

Resumen: Un estudio completro de cohorte que incluya una vigilancia entomológica puede contribuir a nuestro conocimiento de aspectos clínicos y patrones de transmisión de arbovirosis. Este artículo describe la implementación de un estudio poblacional de cohorte de nascimientos que incluyó el componente de vigilancia entomológica y los desafios asociados en una comunidad desfavorecida de Río de Janeiro, Brasil. Los participantes fueron captados en dos periodos: de 2012 a 2014 y de 2015 a 2017. Los niños tenían fijadas consultas pediátrica regulares y por fiebre. Durante las visitas pediátricas, se recogieron datos epidemiológicos y clínicos, así como muestras biológicas. Se realizó una vigilancia activa de la fiebre mediante llamadas telefónicas, redes sociales, aplicaciones de mensajes, y visitas a domicilio. Un total de 387 recién nacidos y 332 nuevos niños fueron incluidos durante el primer y segundo período de reclutamiento, respectivamente. En julio de 2017 se había realizado un seguimiento a 451 niños. Durante el estudio, se realizaron 2.759 visitas pediátricas: 1.783 asintomáticas y 976 por fiebre/urgencias. El número de consultas por fiebre o urgencias aumentó 3.5-veces tras el uso de herramientas de comunicación para la viglancia. No se observaron patrones temporales, estacionalidad o casos de picos de fiebre durante el periodo de estudio. Un total of 10.105 mosquitos adultos (incluyendo 3.523 Aedes spp. y 6.582 Culex quinquefasciatus) y 46.047 huevos fueron recogidos de viviendas, escuelas, y lugares estratégicos. A pesar de los retos, esta cohorte de nacimiento estructurada y supervisada, basada en población es relevante para el conocimiento de los riesgos y la concienciación sobre patógenos emergentes.

Identification of Zika virus in immature phases of Aedes aegypti and Aedes albopictus: a surveillance strategy for outbreak anticipation

A progressive increase in the circulation of arboviruses in tropical countries has been observed, accounting for 700,000 yearly deaths in the world. The main objective of this article was to identify the presence of Zika (ZIKV), dengue (DENV), and Chikungunya (CHIKV) viruses in immature stages of Aedes aegypti and Ae. albopictus. Household collections of immature phases of the vectors were carried out in the years 2015 and 2016. A total of 2902 dwellings were visited and the rate of infestation with larvae and pupae of Aedes mosquitoes was 283/1462 (19.4%) in March 2015 and 55/1440 (3.8%) in June 2015. In March 2015, 907 larvae/pupae were collected (583 or 64.3% of Ae. aegypti and 324 or 35.7% of Ae. albopictus) while in June 2015 there was a reduction in the number of immature forms found: 197 larvae/pupae (121 or 61.4% of Ae. aegypti and 76 or 38.6% of Ae. albopictus). This reduction was accompanied by a decrease in suspected human ZIKV cases from March to June 2015. The RT-qPCR performed in 18 pools identified that three (two of Ae. aegypti and one of Ae. albopictus) were positive for ZIKV, and none were positive for DENV or CHIKV. Our findings demonstrated that ZIKV was present in immature stages of insect vectors in the study region at least five months prior to the peak of ZIKV associated cases. Xenomonitoring of immature phases of the vectors may prove useful for predicting outbreaks.

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.

Entomological investigation of Japanese encephalitis outbreak in Malkangiri district of Odisha state, India

BACKGROUND A severe outbreak of Japanese encephalitis (JE) and acute encephalitis syndrome (AES) with high case fatality was reported from Malkangiri district of Odisha state, India during September to November 2016 affecting 336 children with 103 deaths. OBJECTIVES The purpose of this study was to investigate the outbreak in the light of entomological determinants. METHODS Entomological investigation was carried out in 48 villages from four mostly affected Community Health Centres (CHCs) of Malkangiri district. Dusk collections of resting adults was done in villages from indoor and outdoor sites to record the density of mosquito species, including the known JE vectors, feeding behaviour, parity, dusk index and infection status with JE virus (JEV). FINDINGS The per man hour density and dusk index of JE vector species varied from 2.5 to 24.0 and 0.81 to 7.62, respectively in study villages. A total of 1136 mosquitoes belonging to six vector species were subjected to PCR and one pool of Culex vishnui was found to be positive for JEV. CONCLUSION The JE transmission in Malkangiri district was confirmed. Thorough screening of human blood samples of JE/AES suspected cases and JE vector mosquitoes for the presence of JEV during rainy season every year is recommended.

Successes and failures of sixty years of vector control in French Guiana: what is the next step?

Since the 1940s, French Guiana has implemented vector control to contain or eliminate malaria, yellow fever, and, recently, dengue, chikungunya, and Zika. Over time, strategies have evolved depending on the location, efficacy of the methods, development of insecticide resistance, and advances in vector control techniques. This review summarises the history of vector control in French Guiana by reporting the records found in the private archives of the Institute Pasteur in French Guiana and those accessible in libraries worldwide. This publication highlights successes and failures in vector control and identifies the constraints and expectations for vector control in this French overseas territory in the Americas.