Detecção de flavivirus e alphavirus em mosquitos (diptera: culicidae) capturados em região próxima à Três Lagoas ­ Ms / Detection of flavivirus and alphavirus in mosquitoes (diptera: culicidae) captured in a region close to Tres Lagoas ­ Ms / Detección de flavivirus y alphavirus en mosquitos (diptera: culicidae) capturados en una región cercana a Tres Lagoas ­ Ms

Introdução: Arbovírus são causadores de doenças humanas, sendo que mudança ecológicas e aumento do contato humano-vetor aumenta a possibilidade de surtos. Objetivo: Detectar, identificar e caracterizar arbovírus presentes em mosquitos vetores capturados em regiões de mata próximas a Três Lagoas, MS. Metodologia: Mosquitos foram capturados utilizando armadilhas de luz em regiões de mata circunvizinha a Três Lagoas. Os mosquitos capturados foram classificados por gênero (chave morfológica) e agrupados em pools com até 20 espécimes, e utilizados através da reação de RT-PCR com posterior sequenciamento e análise filogenética. Resultados: Foram capturados 851 dos gêneros: Culex spp. (11 pools); Aedes spp. (13 pools); Haemagogus spp. (7 pools) e outros gêneros não identificados. Sequencias de vírus Dengue (DENV) foram amplificadas de 2/13 (15,38%) pools de Aedes spp. e uma sequência de vírus Mayaro (MAYV) 1/7 (7,7%) foi amplificada de pools de Haemagogus spp. As análises filogenéticas mostraram que as sequências de DENV agrupava-se no clado de DENV1 e DENV2. A sequência de MAYV agrupou-se junto a sequências de amostras de infecções humana por MAYV do grupo L. Conclusão: Estes resultados reforçam a circulação de DENV, que é causador de surtos anuais de doenças febris agudas no município, e detecção, por primeira vez na região, a circulação de MAYV, reforçando a necessidade de monitoramento viral constante nessa região.

Introduction: Arboviruses cause human diseases, and ecological changes and increased human-vector contact increase the possibility of outbreaks. Objective: To detect, identify and characterize arboviruses present in mosquito vectors captured in forest regions close to Tres Lagoas, MS. Methodology: Mosquitoes were captured using light traps in forest regions surrounding Tres Lagoas. The captured mosquitoes were classified by gender (morphological key) and grouped into pools with up to 20 specimens and used through the RT-PCR reaction with subsequent sequencing and phylogenetic analysis. Results: 851 of the genera were captured: Culex spp. (11 pools); Aedes spp. (13 pools); Haemagogus spp. (7 pools) and other unidentified genera. Dengue virus (DENV) sequences were amplified from 2/13 (15.38%) pools of Aedes spp. and a Mayaro virus (MAYV) sequence 1/7 (7.7%) were amplified from pools of Haemagogus spp. Phylogenetic analyzes showed that one of the DENV sequences clustered in the DENV1 and DENV2 clade. The MAYV sequence was grouped together with sequences from samples of human MAYV infections of the L group. Conclusion: These results reinforce the circulation of DENV, which causes annual outbreaks of acute febrile illnesses in the municipality, and detection, for the first time in the region, the circulation of MAYV, reinforcing the need for constant viral monitoring in this region.

Introducción: Los arbovirus causan enfermedades humanas, y los cambios ecológicos y el mayor contacto humano-vector aumentan la posibilidad de brotes. Objetivo: Detectar, identificar y caracterizar arbovirus presentes en mosquitos vectores capturados en regiones de selva próximas a Tres Lagoas, MS. Metodología: Los mosquitos fueron capturados utilizando trampas de luz en las regiones forestales que rodean Tres Lagoas. Los mosquitos capturados fueron clasificados por género (clave morfológica) y agrupados en pools de hasta 20 ejemplares, y utilizados mediante la reacción RT-PCR con posterior secuenciación y análisis filogenético. Resultados: Se capturaron 851 de los géneros: Culex spp. (11 pools); Aedes spp. (13 pools); Haemagogus spp. (7 pools) y otros géneros no identificados. Las secuencias del virus del dengue (DENV) se amplificaron a partir de 2/13 (15,38 %) grupos de Aedes spp. y una secuencia de virus Mayaro (MAYV) 1/7 (7,7%) de pools de Haemagogus spp. Los análisis filogenéticos mostraron que una de las secuencias de DENV se agrupaba en el clado DENV1 y DENV2. La secuencia de MAYV se agrupó con secuencias de muestras de infecciones humanas de MAYV del grupo L. Conclusión: Estos resultados refuerzan la circulación de DENV, causante de brotes anuales de enfermedades febriles agudas en el municipio, y la detección, por primera vez en la región, la circulación de MAYV, reforzando la necesidad de un monitoreo viral constante en esta región.

Low genetic diversity in Wolbachia-Infected Culex quinquefasciatus (Diptera: Culicidae) from Brazil and Argentina / Baixa diversidade genética em Culex quinquefasciatus (Diptera: Culicidae) infectado por Wolbachia do Brasil e Argentina

Culex quinquefasciatus is a vector of human pathogens, including filarial nematodes and several viruses. Although its epidemiological relevance is known to vary across geographical regions, an understanding of its population genetic structure is still incipient. In light of this, we evaluated the genetic diversity of Cx. quinquefasciatus and Cx. pipiens x Cx. quinquefasciatus hybrids collected from nine localities in Brazil and one site in Argentina. We used mitochondrial genes cox1 and nd4, along with the coxA and wsp genes of the maternally-inherited Wolbachia endosymbiont. The nd4 fragment was invariant between samples, whilst cox1 exhibited four haplotypes that separated two types of Cx. quinquefasciatus, one clustered in southern Brazil. Low sequence diversity was generally observed, being discussed. Both Brazilian and Argentinian mosquitoes were infected with a single Wolbachia strain. As reported in previous studies with these populations, cox1 and nd4 diversity is not congruent with the population structure revealed by nuclear markers or alar morphology. Future Cx. quinquefasciatus research should, if possible, evaluate mtDNA diversity in light of other markers.

Culex quinquefasciatus é vetor de patógenos humanos, incluindo nematódeos filarídeos e vários vírus. Embora a sua relevância epidemiológica varie entre as diferentes regiões geográficas, o conhecimento da estrutura genética da população é ainda incipiente. Em vista disso, foram avaliados os níveis de diversidade genética de Cx. quinquefasciatus e de híbridos Cx. quinquefasciatus x Cx. pipiens de nove cidades do Brasil e em La Plata, na Argentina. Para os testes foram utilizados fragmentos dos genes mitocondriais cox1 e nd4, juntamente com coxA e wsp do endossimbionte Wolbachia, herdado maternalmente. O fragmento nd4 não apresentou variação entre as amostras, e o cox1 exibiu quatro haplótipos que separaram dois tipos de Cx. quinquefasciatus, com um deles agrupado no sul do Brasil. Os dados de sequência mostraram baixa diversidade, sendo esta discutida. Ambas as amostras de mosquitos brasileiros e argentinos estão infectados com uma única cepa de Wolbachia. A diversidade apresentada por nd4 e cox1 não é congruente com a estrutura da população revelada por marcadores nucleares e morfologia alar de estudos anteriores com estas mesmas populações. Pesquisas com Cx. quinquefasciatus devem, se possível, avaliar a diversidade por DNA mitocondrial na luz de outros marcadores.

Primer registro para el estado Bolívar de Culex (Lutzia) bigoti Bellardi, 1862 (Diptera: Culicidae) / First record of Culex (Lutzia) bigoti Bellardi, 1862 (Diptera: Culicidae) un Bolivar state, Venezuela

En el presente trabajo se reporta por primera vez para el estado Bolívar la presencia de Culex (Lutzia) bigoti Bellardi. Con este nuevo registro la distribución geográfica de esta especie en Venezuela incluye hasta ahora doce (12) estados y el Distrito Federal

In this work we report for the first time the presence of Culex (Lutzia) bigoti Bellardi in Bolivar state. With this new record the geographical distribution of this species in Venezuela include so far twelve (12) states and the Distrito Federal

Studies on mosquito borne dieases in Egypt and Qatar

Mosquitoes identification, distribution and densities in representative Egyptian Governorates and five Qatarain Municipalities [Al Rayyan, Doha, Al Daayan, Al Khor and Al Zahakira and Al Shamal] were studied. In Qatar the larvae were Culex pipiens complex, C. univettatus, C. pusillus, Aedes caspies, Anopheles multicolor and A. stephensi. C. pipiens and C. univettatus were mainly in Al Rayyan, Doha, and Al Khor and Al Zahakira. C. pusillus was in Doha and Al Daayan while A. caspies was in Al Daayan and Al Shamal. Anopheles multicolor and A. stephensi were mainly in Al Shamal with low density in Al Rayyan [only in Ain- Khalid locution]. The Egyptian mosquitoes were C. pipiens, C. antennatus, C. thelerei, C. univittatus, C. perexiguus, C. poicilipes, C. pusillus, Aedes caspius, Ae. detritus, A. sergentii, A. pharoensis, A. multicolor, A. detail, A. algeriensis, A. tene-brosus, A. gambiae [formerly], A. superpictus, A. tarkhadi, A. hispaniola, A. rhodesiensis, A. stephensi, A. coustani and Culiseta longiareolata. As an example in Sharkia Governorate, larvae were C. pipiens [68.77%], Ae. caspius [15.75%], Culiseta sp. [=Theobaldia] and C. pusillus. In Greater Cairo, parts of Qualyoubia G., C. pipiens was the most dominant and the least was C. perexiguus. In parts of Giza G., C. pipiens was the most dominant and least was Cs. longiareolata. In Cairo G., C. pipiens was the most dominant and least was Ae. caspius. The overall in Greater Cairo was C. pipiens [61.74%], Cs. longiareolata [15.56%], Ae. caspius [15.3%], C. pusillus [4.0%] and C. perexiguus [3.16%]

Effect of entomopathogenic fungus, Beauveria bassiana on larvae of three species of mosquitoes.

Beauveria bassiana, an entomopathogenic fungus, was evaluated for its potential against second and third instar larvae of Culex quinquefasciatus, Anopheles stephensi and Aedes aegypti. Conidiospores of this fungus were effective in causing infection leading to mortality of different larval instars. Larvae of Cx. quinquefasciatus were more susceptible to infection than An. stephensi and the second instar larvae of these two species were more susceptible than third instar larvae. Larvae of Ae. aegypti were resistant to infection by B. bassiana.

Efficacy of a Bacillus sphaericus formulation as influenced by the quality of Culex quinquefasciatus breeding waters.

To understand the physico-chemical factors that influence the efficacy of B. sphaericus formulation in the breeding sites of Culex quinquefasciatus, a study was carried out in Mayiladuturai area of Tamil Nadu (India). The factors studied were hydrogen ion concentration (pH), acidity, alkalinity, chlorides, phosphates, total hardness, sulphates, total solids, dissolved solids, suspended solids, nitrate nitrogen, ammoniacal nitrogen, dissolved oxygen, biological oxygen demand (BOD) and chemical oxygen demand (COD). Efficacy of the formulation was assessed in terms of reduction in larval population in the treated habitats. pH of water in the treated sites was around neutral range (mean +/- SD 7.65 +/- 0.23). Phosphate content was low (2.27 +/- 1.34 ppm) whereas chlorides (326.1 +/- 55.8 ppm) and sulphates (38.9 +/- 23.8 ppm) were high. Total hardness ranged from 206 to 462.5 ppm with a mean of 312.1 +/- 80.5 ppm. The chlorides and sulphates, though present in considerable quantity, did not have any influence on the efficacy of B. sphaericus formulation. However, the proportion of insoluble chlorides and sulphates which contribute to total hardness seemed to influence the formulation adversely.

A modified bioassay for microbial mosquito larvicides.

The proposed bioassay-the grid assay-eliminates the influence of cannibalism while allowing recycling to take place. The LC50 values of the grid assay were intermediate to those of the group and the individual assay. The grid assay thus reflects the true toxicity values of the microbial pesticides being tested. Viable count studies of the microbial pesticides employed, viz., Bacillus thuringiensis H-14 and Bacillus sphaericus 2362, performed along with the assay support the results of the bioassay.

Serological characterization of 23 isolates of Bacillus sphaericus, pathogenic to mosquito larvae, screened from Brazilian soil

Através da sorologia flagelar foram caracterizados 23 isolados de Bacillus sphaericus obtidos em amostras de solo provenientes de diferentes regiöes do Brasil. Todos säo patogênicos para Culex quinquefasciatus e todos pertencem ao sorotipo H5. Esta caracterizaçäo sorológica mostrou que entre os isolados de Bacillus sphaericus brasileiros näo existem diferenças regionais. Adaptaçäo da metodologia se mostrou eficiente, diminuindo o tempo de reaçäo e a quantidade de material utilizado

Dengue in Gujarat state, India during 1988 & 1989.

Following the reports of epidemics of febrile illness from several rural and urban areas of Gujarat state (India) in 1988, epidemiological investigations were carried out and dengue (DEN) virus activity was demonstrated in large cities such as Surat and Rajkot as well as several villages in Sabarkantha district. Two strains of dengue type-2 each were isolated from human sera from Surat city and a village in Sabarkantha district. Six strains of dengue virus were isolated from Aedes aegypti mosquitoes collected at Chotasan village, two of which were confirmed as DEN type-2. Of the 560 patients' sera tested from different areas (including villages and townships), 122 showed evidence of dengue infection and another 236 showed a broader reaction with flaviviruses. Entomological investigations showed a widespread distribution of Ae. aegypti both in urban and rural areas. In the household conditions this mosquito was found to breed predominantly in containers with non-potable water. Amongst these, cement containers manufactured in towns and distributed to the villages seem to play an important role in the spread of this species. In non-residential areas prolific breeding of Ae. aegypti was observed in automobile tyre dumps, and varied types of scrap, in towns and villages. Distribution and relative prevalence of the species were studied in 46 towns and villages, covering the spectrum of rural-urban-continuum. These studies provide an indication regarding the mechanism of the spread of DEN virus through peoples' movement, transport, the process of urbanisation etc.

Ecology of mosquitos (Diptera: Culicidae) at a site endemic with Japanese encephalitis on Luzon, Republic of the Philippines.

A 2-year study of the ecology of mosquitos was conducted in a rice-growing area in the Philippines. Forty-four species in 8 genera were collected using 6 techniques, with Culex vishnui being most abundant. Of all the Anopheles collected, most species were exophagic, while most of the Culex species collected were endophagic. Anthropophilic or zoophilic feeding patterns were estimated using man-to-animal biting ratios. Peak periods of mosquito abundance occurred several months after the onset of both the rainy season and the rice irrigation period. Seasonal populations of the more abundant species revealed 3 distinct patterns: 1) populations are high during the rainy season and low during the irrigation period; 2) populations are equally strong during both periods; and 3) populations are highest during the irrigation period. Species' biting activity was grouped into 2 patterns: 1) those that feed primarily from 1800-0000; and 2) those that feed evenly throughout the night. Mosquito abundance and Japanese encephalitis virus activity were related to rainfall and rice-growing practices.

Isolation of Getah virus from mosquitos collected on Hainan Island, China, and results of a serosurvey.

An isolate of Getah virus was obtained from Culex mosquitos collected in Mao'an Village, Baoting County, Hainan Province, China, in 1964. The virus (strain M-1) replicated in laboratory-bred Aedes aegypti and Cx. fatigans (= quinquefasciatus), and was transmitted by laboratory-bred Ae. albopictus to healthy newborn albino mice. Skeletal muscles of newborn albino mice experimentally infected with the virus showed degeneration, atrophy, necrosis, and inflammatory changes of muscle fibers. Antibody prevalence in humans and animals ranged from 10.3% by neutralization tests of samples from healthy people in 1979 to 26.4% by CF tests of samples from people with febrile illnesses in 1982. The high prevalence of antibody in pigs, horses, and goats (17.6% to 37.5%) indicated that infection with Getah or a closely related virus is relatively common in domestic animals.

Microbial flora in gut of Culex quinquefasciatus breeding in cess pits.

The number and types of microorganisms in the gut of Culex quinquefasciatus larvae varied considerably from one site of collection to another. Larval gut, in general, contained enormous number of bacteria, a few fungi and negligible number of actinomycetes which belonged to 15 bacterial, 6 fungal and 4 actinomycete genera, respectively. Bacillus sp., Staphylococcus sp. and Pseudomonas sp. among bacteria, Aspergillus among fungi and Streptomyces sp. among actinomycetes were frequently encountered. Escherichia, Proteus, Aspergillus and Streptomyces were the most abundant genera. Isolates of Bacillus, Pseudomonas, Shigella and Staphylococcus caused 100% mortality during the early instar of larval development. None of the fungal isolates effected 100% mortality while Nocardiopsis sp. among actinomycetes gave 100% mortality. One of the Escherichia isolate suppressed the adult emergence completely while 27 others, belonging to most of the genera found, suppressed significantly. Isolates of Aspergillus, Alternaria and Streptomyces inhibited the emergence of adults completely.

Transmission of Japanese encephalitis virus in Culex pseudovishnui & C. tritaeniorhynchus mosquitoes.

Studies on the transovarial transmission of Japanese encephalitis virus (JEV) by orally infected female C. pseudovishnui showed that these mosquitoes were capable of transmitting JEV by bite to susceptible hosts. Infected females also transmitted the virus vertically to its first generation progeny. In another experiment, C. tritaeniorhynchus was also shown capable of transmitting the virus vertically to its first generation progeny. However, there was no apparent difference in transovarial transmission capabilities of these two species in orally infected mosquitoes.

Isolation of Japanese encephalitis virus from Culex pseudovishnui Colless, 1957 (Diptera: Culicidae) in Goa.

A strain of Japanese encephalitis virus was isolated from a pool of 54 female C. pseudovishnui Colless, 1957. The mosquitoes were collected in August 1988 during the period of epidemic of JE. This is the first report of isolation of JE virus from mosquitoes in Goa in the western coastal belt of peninsular India. In view of this isolation, C. pseudovishnui acquires greater importance, even though its density and relative prevalence during the current study was found to be far lower than C. tritaeniorhynchus.

Studies on Japanese encephalitis vectors in Indonesia.

Entomologic surveys indicated that JE vectors in Indonesia are Cx. tritaeniorhyncus and Cx. gelidus. In most study areas, the former were predominant among all the culicine mosquitoes. The seasonal abundance of the two JE vector species was correlated significantly with the rainfall. The virus activity was parallel to the seasonal fluctuation of the vectors suggesting that the transmission of the disease would depend on the population dynamics of the vectors.

Primeiro registro de epidemias causadas pelo vírus Oropouche nos estados do Maranhäo e Goiás, Brasil / 1st register of an epidemic caused by Oropouche virus in the states of Maranhäo and Goiás, Brazil

Os autores descrevem a ocorrência de epidemias causadas pelo vírus Oropouche (Oro) nos Estados dpo Maranhäo (MA) e Goiás (GO) em 1988. 36 amostras de vírus foram obtidas a partir da inoculaçäo do sangue de 120 pacientes em camundongos recém nascidos. A doença foi caracterizada por febre, cefaléia, dores musculares, articulares, fotofobia, dor retro ocular, náuseas e tontura. 128 das 197 pessoas examinadas em Porto Franco, MA, tinham anticorpos inibidores da hemaglutinaçäo (IH) para o agente e, em 106 foram detectados anticorpos IGM por MACELISA. Todos os grupos etários foram infectados, embora a incidência tenha sido mais elevada entre aqueles com 10 a 19 anos de idade. Quanto ao sexo, a infecçäo ocorreu igualmente em ambos os sexos. Recorrência dos sintomas foi observada em 56% dos casos positivos estudados. A inoculaçäo em camundongos Swiss recém nascidos de 3.624 Culicoides paraensis (Ceratopogonidae) e 1.970 Culex (Culex) quinquefasciatus (Culicidae), coletados em Porto Francos-MA, resultou em um único isolamento do vírus ORO a partir dos Culicoides. Essa é a primeira descriçäo de casos confirmados de infecçäo pelo vírus Oropouche nos Estados do Maranhäo e Goiás, Brasil

A longitudinal study of Japanese encephalitis in suburban Bangkok, Thailand.

A one-year study of Japanese encephalitis (JE) in a small focus of transmission was conducted in suburban Bangkok in 1985. Monthly data were collected on weather, vector density, sentinel pig and chick JE antibody seroconversions, and epidemiology as related to human JE cases. The primary vector species were found to be Culex gelidus and Culex tritaeniorhynchus; from which one isolate each was obtained in March and June, respectively. Pig JE antibody seroconversion peaked in April (the hottest month), with secondary peaks following in July and December. Chick seroconversions were found only in June and July. Human cases (7) in the primary focus occurred from May-July, and started 2 months following the finding of the first JEV isolate in mosquitoes and 1 month following mass JEV seroconversion in pigs. Overall, the attack rate in the focus (0.83/10(5] was greater than 4 times that of the rest of Bangkok (0.19/10(5]. Attack rates were highest in 0-9 and 10-19 year-old groups, respectively. Indications are that JEV is transmitted to humans in Bangkok at least 10 out of 12 months per year, but that cases are concentrated in the May to July period.