Late effects of Beauveria bassiana on larval stages of Aedes aegypti Linneo , 1762 (Diptera: Culicidae) / Efeitos tardios de Beauveria bassiana nos estágios larvais de Aedes aegypti Linneo, 1762 (Diptera: Culicidae)

Aedes aegypti is a culicide that has gained relevance over the years due to its ability to transmit various viruses that cause diseases in humans that all the years cause high mortality rates in the world population. The main problem is that Ae. aegypti has managed to establish and maintain a close relationship with humans and their habitat, which is why the search for alternatives to control vector populations becomes imperative. The objective of the present work was to study the effects of two Beauveria bassiana strains on Aedes aegypti. Third instar larvae of Ae. aegypti in 250 mL plastic containers were inoculated with the GHA and NB3 strains at different concentrations (1.5 × 104 , 1.5× 105 , 1.5 × 106 and 1.5 × 107 conidia/mL). The NB3 strain presented highest mortality values with 63% in the highest concentration i.e., 1.5 × 107 , while for the GHA strain the highest mortality value was 30.7% at the same concentration. The results showed significant difference in mortality with respect to the strain and days post treatment (P = 0.0001), but not with respect to the conidial concentration (P = 0.634). The average mortality of larvae per day for the NB3 for different concentrations ranged from 20 to 25 larvae per day, while for the GHA daily mortality ranged from 5 to 12 larvae. In post-treatment mortality, the highest mortality was recorded in the third stage larvae for the NB3, while for GHA the highest percentage mortality was observed in individuals who managed to reach the adult state. The findings of the current research depicted the noteworthy role of B. bassiana for the management of an important vector of human disease.

O Aedes aegypti é um culicida que vem ganhando relevância ao longo dos anos devido à sua capacidade de transmitir diversos vírus causadores de doenças em humanos que ao longo dos anos ocasionam altas taxas de mortalidade na população mundial. O principal problema é que Ae. aegypti tem conseguido estabelecer e manter uma relação próxima com o homem e seu habitat, por isso a busca por alternativas para o controle das populações de vetores torna-se imperativa. O objetivo do presente trabalho foi estudar os efeitos de duas cepas de Beauveria bassiana sobre Ae. aegypti. Larvas de terceiro instar de Ae. aegypti em recipientes plásticos de 250 mL foram inoculados com as cepas GHA e NB3 em diferentes concentrações (1.5 × 104, 1.5 × 105, 1.5 × 106 e 1.5 × 107 conídios/mL). A cepa NB3 apresentou os maiores valores de mortalidade com 63% na concentração mais alta, ou seja, 1.5 × 107, enquanto para a cepa GHA o maior valor de mortalidade foi 30.7% na mesma concentração. Os resultados mostraram diferença significativa na mortalidade com relação à cepa e dias pós-tratamento (P = 0.0001), mas não com relação à concentração de conídios (P = 0.634). A mortalidade média de larvas por dia para o NB3 para diferentes concentrações variou de 20 a 25 larvas por dia, enquanto para o GHA a mortalidade diária variou de 5 a 12 larvas. Na mortalidade pós-tratamento, a maior mortalidade foi registrada nas larvas de terceiro estágio para o NB3, enquanto para o GHA o maior percentual de mortalidade foi observado em indivíduos que conseguiram atingir o estado adulto. Os resultados da pesquisa atual retratam o papel notável de B. bassiana no manejo de um importante vetor de doenças humanas.

Distribution modelling of Aedes aegypti in three dengue-endemic areas in Sumatera, Indonesia

@#Ae. aegypti is a dengue virus vector and a public health threat in Indonesia. Furthermore, the Dengue Haemoragic Fever (DHF) has spread to all cities in the country, including Bandar Lampung. A species distribution model, Maximum Entropy (MaxEnt), was used to predict the geographic distribution of this vector in three dengue-endemic areas, namely Sukarame, Kemiling, and Tanjung Seneng. Previously, surveillance was conducted to determine the presence of Ae. aegypti. Therefore, this study suggested that environmental variables such as rainfall, temperature, land cover, and population density have influenced the widespread of Ae. aegypti and facilitate its proliferation in the study areas. The influence of the environmental variables was analyzed using a response curve. The model performance was measured by percent contribution, the importance of permutations, and the jackknife test. This study’s evaluation indicates that the certainty models for the presence of Ae. aegypti in Sukarame, Kemiling, and Tanjung Seneng were developed extremely well, with respective values of 0.989, 0.993, and 0.969. The results showed that Ae. aegypti is widespread in the three endemic areas. The high population density and land conversion into settlements are influential environmental variables essential in determining the distribution of the vector in three areas of Bandar Lampung. Climatic factors such as rainfall and temperature are supporting aspects in maintaining the habitat of Ae. aegypti in the area. Mapping areas at risk of this dengue vector can aid in planning disease management strategies and identifying priority locations for entomological surveys to control epidemics.

Late effects of Beauveria bassiana on larval stages of Aedes aegypti Linneo, 1762 (Diptera: Culicidae) / Efeitos tardios de Beauveria bassiana nos estágios larvais de Aedes aegypti Linneo, 1762 (Diptera: Culicidae)

Aedes aegypti is a culicide that has gained relevance over the years due to its ability to transmit various viruses that cause diseases in humans that all the years cause high mortality rates in the world population. The main problem is that Ae. aegypti has managed to establish and maintain a close relationship with humans and their habitat, which is why the search for alternatives to control vector populations becomes imperative. The objective of the present work was to study the effects of two Beauveria bassiana strains on Aedes aegypti. Third instar larvae of Ae. aegypti in 250 mL plastic containers were inoculated with the GHA and NB3 strains at different concentrations (1.5 × 104, 1.5× 105, 1.5 × 106 and 1.5 × 107 conidia/mL). The NB3 strain presented highest mortality values with 63% in the highest concentration i.e., 1.5 × 107, while for the GHA strain the highest mortality value was 30.7% at the same concentration. The results showed significant difference in mortality with respect to the strain and days post treatment (P = 0.0001), but not with respect to the conidial concentration (P = 0.634). The average mortality of larvae per day for the NB3 for different concentrations ranged from 20 to 25 larvae per day, while for the GHA daily mortality ranged from 5 to 12 larvae. In post-treatment mortality, the highest mortality was recorded in the third stage larvae for the NB3, while for GHA the highest percentage mortality was observed in individuals who managed to reach the adult state. The findings of the current research depicted the noteworthy role of B. bassiana for the management of an important vector of human disease.

O Aedes aegypti é um culicida que vem ganhando relevância ao longo dos anos devido à sua capacidade de transmitir diversos vírus causadores de doenças em humanos que ao longo dos anos ocasionam altas taxas de mortalidade na população mundial. O principal problema é que Ae. aegypti tem conseguido estabelecer e manter uma relação próxima com o homem e seu habitat, por isso a busca por alternativas para o controle das populações de vetores torna-se imperativa. O objetivo do presente trabalho foi estudar os efeitos de duas cepas de Beauveria bassiana sobre Ae. aegypti. Larvas de terceiro instar de Ae. aegypti em recipientes plásticos de 250 mL foram inoculados com as cepas GHA e NB3 em diferentes concentrações (1.5 × 104, 1.5 × 105, 1.5 × 106 e 1.5 × 107 conídios/mL). A cepa NB3 apresentou os maiores valores de mortalidade com 63% na concentração mais alta, ou seja, 1.5 × 107, enquanto para a cepa GHA o maior valor de mortalidade foi 30.7% na mesma concentração. Os resultados mostraram diferença significativa na mortalidade com relação à cepa e dias pós-tratamento (P = 0.0001), mas não com relação à concentração de conídios (P = 0.634). A mortalidade média de larvas por dia para o NB3 para diferentes concentrações variou de 20 a 25 larvas por dia, enquanto para o GHA a mortalidade diária variou de 5 a 12 larvas. Na mortalidade pós-tratamento, a maior mortalidade foi registrada nas larvas de terceiro estágio para o NB3, enquanto para o GHA o maior percentual de mortalidade foi observado em indivíduos que conseguiram atingir o estado adulto. Os resultados da pesquisa atual retratam o papel notável de B. bassiana no manejo de um importante vetor de doenças humanas.

Late effects of Beauveria bassiana on larval stages of Aedes aegypti Linneo, 1762 (Diptera: Culicidae)

Abstract Aedes aegypti is a culicide that has gained relevance over the years due to its ability to transmit various viruses that cause diseases in humans that all the years cause high mortality rates in the world population. The main problem is that Ae. aegypti has managed to establish and maintain a close relationship with humans and their habitat, which is why the search for alternatives to control vector populations becomes imperative. The objective of the present work was to study the effects of two Beauveria bassiana strains on Aedes aegypti. Third instar larvae of Ae. aegypti in 250 mL plastic containers were inoculated with the GHA and NB3 strains at different concentrations (1.5 × 104, 1.5× 105, 1.5 × 106 and 1.5 × 107 conidia/mL). The NB3 strain presented highest mortality values with 63% in the highest concentration i.e., 1.5 × 107, while for the GHA strain the highest mortality value was 30.7% at the same concentration. The results showed significant difference in mortality with respect to the strain and days post treatment (P = 0.0001), but not with respect to the conidial concentration (P = 0.634). The average mortality of larvae per day for the NB3 for different concentrations ranged from 20 to 25 larvae per day, while for the GHA daily mortality ranged from 5 to 12 larvae. In post-treatment mortality, the highest mortality was recorded in the third stage larvae for the NB3, while for GHA the highest percentage mortality was observed in individuals who managed to reach the adult state. The findings of the current research depicted the noteworthy role of B. bassiana for the management of an important vector of human disease.

Resumo O Aedes aegypti é um culicida que vem ganhando relevância ao longo dos anos devido à sua capacidade de transmitir diversos vírus causadores de doenças em humanos que ao longo dos anos ocasionam altas taxas de mortalidade na população mundial. O principal problema é que Ae. aegypti tem conseguido estabelecer e manter uma relação próxima com o homem e seu habitat, por isso a busca por alternativas para o controle das populações de vetores torna-se imperativa. O objetivo do presente trabalho foi estudar os efeitos de duas cepas de Beauveria bassiana sobre Ae. aegypti. Larvas de terceiro instar de Ae. aegypti em recipientes plásticos de 250 mL foram inoculados com as cepas GHA e NB3 em diferentes concentrações (1.5 × 104, 1.5 × 105, 1.5 × 106 e 1.5 × 107 conídios/mL). A cepa NB3 apresentou os maiores valores de mortalidade com 63% na concentração mais alta, ou seja, 1.5 × 107, enquanto para a cepa GHA o maior valor de mortalidade foi 30.7% na mesma concentração. Os resultados mostraram diferença significativa na mortalidade com relação à cepa e dias pós-tratamento (P = 0.0001), mas não com relação à concentração de conídios (P = 0.634). A mortalidade média de larvas por dia para o NB3 para diferentes concentrações variou de 20 a 25 larvas por dia, enquanto para o GHA a mortalidade diária variou de 5 a 12 larvas. Na mortalidade pós-tratamento, a maior mortalidade foi registrada nas larvas de terceiro estágio para o NB3, enquanto para o GHA o maior percentual de mortalidade foi observado em indivíduos que conseguiram atingir o estado adulto. Os resultados da pesquisa atual retratam o papel notável de B. bassiana no manejo de um importante vetor de doenças humanas.

A study to identify the presence of Aedes Spp. using BG-Sentinel® Traps and larval/pupal surveys in communities around Belmopan, Cayo District.

The knowledge of the presence of Aedes Spp. mosquitoes is very important for the prevention and control of emerging and remerging diseases caused by Arboviruses such as: Yellow fever, Dengue, Chikungunya and Zika. While Chikungunya and Dengue are endemic to Belize, Zika is currently a threat with local transmission having been established in several Caribbean and Central American Countries. The objective of the study is to survey the presence of Ae. aegypti and Ae. albopictus in the communities of San Martin, Salvapan and Las Flores, Belmopan City. The study was conducted from March 14 to April 2, 2016 whereby adult mosquitoes were captured using BG-Sentinel® Traps and larvae/pupae collection surveys were also done. Three hundred meter zone(s) were determined within localities and 1 BG-Sentinel® trap was deployed for 3 days at 24-hour intervals both indoors and outdoors at 2 residences randomly selected in each community. Larvae/Pupae collection surveys were done at 5 private premises within the predetermined zones in each of the three communities. Captured larvae and Pupae were reared for 6 days and adults obtained were used for identification. The identification of adult Ae. aegypti and Ae. albopictus was done using a stereoscopic microscope and pictorial keys that are used for the identification of mosquitoes. The presence of Ae. aegypti was identified in all 3 communities through both adult mosquito and larvae/pupae collections. However, Ae. albopictus was present only in San Martin and Salvapan communities. The presence of Ae. aegypti and/or Ae. albopictus will determine which appropriate vector control interventions are needed considering the different characteristic breeding habitats of these mosquitoes.(AU)

Persistencia en la competencia vectorial de Aedes albopictus de Venezuela a una cepa asiática dengue 2 / Vector competence persistance of Venezuelan Aedes albopictus for an Asian dengue-2 strain

En Venezuela, existen poblaciones de Aedes aegypti (Ae. aegypti) de diferente origen geográfico y estructura genética que difieren en la competencia vectorial para el virus dengue. Debido a que, recientemente, se reportó la presencia de Aedes albopictus (Ae. albopictus), es importante también conocer la competencia vectorial de esta especie para prever el riesgo epidemiológico el cual conlleva a su propagación. Se determinó la persistencia en la competencia vectorial de Ae. albopictus de Maracay, Venezuela a una cepa asiática dengue 2. Las especies de mosquitos Ae. albopictus y Ae. aegypti fueron alimentadas con una suspensión sangre-virus dengue 2 y luego de 20 días post-exposición viral se determinó la presencia del virus por el ensayo de la reacción en cadena de la polimerasa (PCR) en las diferentes partes de los insectos: abdomen (infección), patas/alas (diseminación) y cabeza (transmisión). Los resultados muestran que la cepa Ae. aegypti es más susceptible a la infección del abdomen (60 %) que la cepa de Ae. albopictus (37,5%); sin embargo, sólo en Ae. albopictus se encontró el virus presente en las patas/alas (100%) y cabezas (33%). La cepa de Ae. albopictus estudiada podría ser más competente para la transmisión del virus dengue asiático que la de Ae. aegypti. Este hallazgo es de gran importancia epidemiológica, ya que se demuestra que este vector aún no estando en su continente de origen, puede seguir siendo un vector eficiente y con el tiempo adecuarse a las cepas virales propias.

In Venezuela, there are populations of Aedes aegypti (Ae. aegypti) with different geographic origins and genetic structure that differ in vector competence for dengue virus. Since recently, the presence of Aedes albopictus (Ae. albopictus) was reported, it is also important to know the vector competence of this species to predict the epidemiological risk which would bring its spread. The objective was to determine the vector competence persistance of Ae. albopictus from Maracay, Venezuela for an Asian dengue-2 strain. The two species of mosquitoes were fed with a blood-dengue 2 virus suspension and after 20 days post-exposure to virus, the presence of the virus was determined by the polymerase chain reaction assay in different parts of the insect: abdomen (infection), legs/wings (spread) and head (transmission).The results show that the strain Ae. aegypti is more susceptible to infection in the abdomen (60 %) that the strain of Ae. albopictus (37.5%); however, only in Ae. albopictus this virus was found in the legs /wings (100%) and heads (33%). The studied strain of Ae. albopictus may be more competent vector in the transmission of the dengue 2 virus than Ae. aegypti. This finding is of great epidemiological importance as this shows that even this mosquito not being in its continent of origin, it can still be an efficient vector and eventually become adapted to the native viral strains.

Actividad insecticida de extractos vegetales sobre larvas de Aedes aegypti, Diptera: Culicidae / Insecticidal activity of vegetal extracts against Aedes aegypti larvae, Diptera: Culicidae

Introducción: ante la aparición cada vez más frecuente de resistencia de Aedes aegypti a los insecticidas tradicionales, se hace necesario el estudio de extractos vegetales que puedan ser usados como alternativas de control. Objetivo: determinar la actividad insecticida de extractos metanólicos de Gliricidia sepium, Sapindus saponaria y Annona muricata sobre larvas de tercer estadío de Ae. aegypti. Materiales y métodos: mediante percolación metanólica de macerados de las especies vegetales se obtuvieron extractos totales y mediante diluciones de cada extracto se realizaron bioensayos sobre larvas de tercer estadio de Ae. aegypti, cepas Rockefeller y Silvestre. Se realizó análisis PROBIT para la determinar la concentración letal media (LC50) de los extractos evaluados. Resultados: los valores de LC50 hallados para cada uno de los extractos vegetales fueron: A.muricata, 6,48 ppm (IC 95 %: 5,88-7,27); S.saponaria, 601,81 ppm (IC 95 %: 498,41- 690,74); G. sepium, 1328,91 ppm (IC 95 %: 1 201,45-1 448,70), para la cepa Rockefeller. A. muricata, 7,26 ppm (IC 95 %: 6,65-8,05); S. saponaria, 658,64 ppm (IC 95 %: 591,48-730,05); G. sepium, 1 532,89 ppm (IC 95 %: 1 408,15-1 660,70), para la cepa silvestre. Conclusión: Los resultados obtenidos son promisorios para el control de estadios inmaduros de Ae. aegypt.

Introduction: Given the increasingly frequent occurrence of resistance of Ae. aegypti to conventional insecticides, it becomes necessary to study plant extracts that can be used as alternative for control. Objective: To establish the insecticidal activity of metanolic extracts of Gliricidia sepium, Sapindus saponaria and Annona muricata against third instar Ae. aegypti larvae. Materials and methods: A percolation with methanol of macerated plant species to obtain total extracts was performed and then using dilutions of each extract was proceeded to perform bioassays on third stage larvae of Ae. aegypti, strains Rockefeller and wildtype. PROBIT analysis was performed to determine the median lethal concentration (LC50) of the extracts tested. Results: LC50 values found for each of extract are: A. muricata, 6,48 ppm (CI 95 %: 5,88 - 7,27); S. saponaria, 601,81 ppm (CI 95 %: 498,41 - 690,74); G. sepium, 1 328,91 ppm (CI 95 %: 1 201,45 - 1 448,70), Rockefeller strain. A. muricata, 7,26 ppm (CI 95 %: 6,65 - 8,05); S. saponaria, 658,64 ppm (CI 95 %: 591,48 -730,05); G. sepium, 1 532,89 ppm (CI 95 %: 1 408,15 - 1 660,70), for wildtype strain. Conclusion: The results are promising for the control of immature stages of Ae. aegypti.

Fatores epidemiológicos do dengue na região central do estado do Rio Grande do Sul, Brasil, 2007 - 2010 / Epidemiological features of dengue in the central region of Rio Grande do Sul state, Brazil, from 2007 to 2010

O objetivo deste estudo foi avaliar fatores epidemiológicos do dengue, nos municípios da 4ª Coordenadoria Regional de Saúde/RS (4a CRS/RS), nos anos de 2007 a 2010. Trata-se de um estudo descritivo, empregando como variáveis: município de notificação; ano de notificação; sexo e faixa etária do paciente; índice de infestação predial (IIP) e índice de Breteau (IB). Foram constatados 13 casos importados da doença, em cinco municípios, sendo a maior ocorrência em Santa Maria. Houve notificação de casos em ambos os sexos e em diferentes faixas etárias. Focos positivos do Aedes aegypti foram encontrados em armadilhas instaladas em pontos estratégicos de Santa Maria e Santiago. O IIP e IB, em ambos os municípios, não representaram risco à saúde pública. Conclui-se, portanto, que as ações de vigilância em saúde devem ser fomentadas com o objetivo de orientar as práticas de controle do vetor, bem como promover a educação sanitária e ambiental, a fim de impedir a instalação de casos autóctones nos municípios estudados.

The aim of this study was to evaluate the epidemiological issues of dengue in the counties of the 4th Coordenadoria Regional de Saúde (government agency to surveillance on public health) of Rio Grande do Sul state, Brazil, during 2007 to 2010. This is a descriptive study, using as variables: cities where dengue was reported; year; sex and age of the patient; infestation (IIP) and Breteau (BI) index. A total of 13 imported cases of the dengue was reported in five cities and higher occurrence was in Santa Maria city. There were notifications of dengue in both sex and in different age groups. Positive foci of Aedes aegypti were found in the traps at strategic points in both cities, Santa Maria and Santiago. BII and BI varied during the studied period in both cities, and, so far, they did not constitute a risk to public health. We conclude that the health surveillance should be enhanced with the purpose of guiding vector control practices, as well as promote health and environmental education in order to prevent the installation of autochthonous dengue cases in the cities studied.

Research on susceptibility of mosquito Ae. aegypti to insecticides in some Northern provinces between 2001 and 2004

Aedes aegypti mosquitoes had been collected at field of some Northern provinces between 2001 and 2004 for studies of their susceptibility to insecticides. It was seen that: all of tested mosquitoes dropped immediately 100% and 100% killed after 24 hours. The results showed that all tested mosquitoes were highly susceptible to insecticides, such as permethrin, lambda cyhalothrin, and malathion from 2001-2004 in Northern region. The provinces participate in the test was up fro 5-7. Using the insecticides to kill Aedes aegypti by ULV spraying was effective in Northern provinces in Vietnam. It is adviced to send mosquitoes and lavae in June and July when the density of mosquitoes and lavae is high. Therefore, expanding studies to other provinces throughout the country to identify susceptibility of Aedes aegypti to insecticides is very necessary for Dengue Hemorrhagic Fever vector control.