Salivary gland proteins of the human malaria vector, Anopheles dirus B (Diptera: Culicidae)

Salivary gland proteins of the human malaria vector, Anopheles dirus B were determined and analyzed. The amount of salivary gland proteins in mosquitoes aged between 3 - 10 days was approximately 1.08 ± 0.04 µg/female and 0.1 ± 0.05 µg/male. The salivary glands of both sexes displayed the same morphological organization as that of other anopheline mosquitoes. In females, apyrase accumulated in the distal regions, whereas alpha-glucosidase was found in the proximal region of the lateral lobes. This differential distribution of the analyzed enzymes reflects specialization of different regions for sugar and blood feeding. SDS-PAGE analysis revealed that at least seven major proteins were found in the female salivary glands, of which each morphological region contained different major proteins. Similar electrophoretic protein profiles were detected comparing unfed and blood-fed mosquitoes, suggesting that there is no specific protein induced by blood. Two-dimensional polyacrylamide gel analysis showed the most abundant salivary gland protein, with a molecular mass of approximately 35 kilodaltons and an isoelectric point of approximately 4.0. These results provide basic information that would lead to further study on the role of salivary proteins of An. dirus B in disease transmission and hematophagy.

First record of Anopheles (Anopheles) costai Fonseca & Ramos, 1939 in Espírito Santo State, Brazil

Field collections of immatures and adults of Culicidae were carried out in the Rio Doce Valley, Espírito Santo State, aiming to increase knowledge on the anopheline species of that region. Considering all Culicidae species collected, among other anopheline it is noteworthy the presence of Anopheles darlingi, An. oswaldoi and An. costai. Regarding to An. darlingi, responsible for malaria outbreak in the low lands in that state, it was expected to confirm its presence in the area. The register of specimens of An. costai in the field collections is relevant, increasing the geographical distribution of the species and representing better knowledge of the Series Arribalzagia of the subgenus Anopheles.

Brazilian mosquito (Diptera: Culicidae) fauna: I. Anopheles species from Porto Velho, Rondônia state, western Amazon, Brazil

This study contributes to knowledge of Anopheles species, including vectors of Plasmodium from the western Brazilian Amazon in Porto Velho, Rondônia State. The sampling area has undergone substantial environmental changes as a consequence of agricultural and hydroelectric projects, which have caused intensive deforestation and favored habitats for some mosquito species. The purpose of this study was to diagnose the occurrence of anopheline species from collections in three locations along an electric-power transmission line. Each locality was sampled three times from 2010 to 2011. The principal adult mosquitoes captured in Shannon trap were Anopheles darlingi, An. triannulatus, An. nuneztovari l.s., An.gilesi and An. costai. In addition, larvae were collected in ground breeding sites for Anopheles braziliensis, An. triannulatus, An. darlingi, An. deaneorum, An. marajoara, An. peryassui, An. nuneztovari l.s. and An. oswaldoi-konderi. Anopheles darlingi was the most common mosquito in the region. We discuss Culicidae systematics, fauna distribution, and aspects of malaria in altered habitats of the western Amazon.

Anopheles (Kerteszia) cruzii (DIPTERA: CULICIDAE) IN PERIDOMICILIARY AREA DURING ASYMPTOMATIC MALARIA TRANSMISSION IN THE ATLANTIC FOREST: MOLECULAR IDENTIFICATION OF BLOOD-MEAL SOURCES INDICATES HUMANS AS PRIMARY INTERMEDIATE HOSTS

Anopheles (Kerteszia) cruzii has been implicated as the primary vector of human and simian malarias out of the Brazilian Amazon and specifically in the Atlantic Forest regions. The presence of asymptomatic human cases, parasite-positive wild monkeys and the similarity between the parasites infecting them support the discussion whether these infections can be considered as a zoonosis. Although many aspects of the biology of An. cruzii have already been addressed, studies conducted during outbreaks of malaria transmission, aiming at the analysis of blood feeding and infectivity, are missing in the Atlantic Forest. This study was conducted in the location of Palestina, Juquitiba, where annually the majority of autochthonous human cases are notified in the Atlantic Forest of the state of São Paulo. Peridomiciliary sites were selected for collection of mosquitoes in a perimeter of up to 100 m around the residences of human malaria cases. The mosquitoes were analyzed with the purpose of molecular identification of blood-meal sources and to examine the prevalence of Plasmodium. A total of 13,441 females of An. (Ker.) cruzii were collected. The minimum infection rate was calculated at 0.03% and 0.01%, respectively, for P. vivax and P. malariae and only human blood was detected in the blood-fed mosquitoes analyzed. This data reinforce the hypothesis that asymptomatic human carriers are the main source of anopheline infection in the peridomiciliary area, making the probability of zoonotic transmission less likely to happen.

SEASONAL DISTRIBUTION OF MALARIA VECTORS (DIPTERA: CULICIDAE) IN RURAL LOCALITIES OF PORTO VELHO, RONDÔNIA, BRAZILIAN AMAZON

We conducted a survey of the malaria vectors in an area where a power line had been constructed, between the municipalities of Porto Velho and Rio Branco, in the states of Rondônia and Acre, respectively. The present paper relates to the results of the survey of Anopheles fauna conducted in the state of Rondônia. Mosquito field collections were performed in six villages along the federal highway BR 364 in the municipality of Porto Velho, namely Porto Velho, Jaci Paraná, Mutum Paraná, Vila Abunã, Vista Alegre do Abunã, and Extrema. Mosquito captures were performed at three distinct sites in each locality during the months of February, July, and October 2011 using a protected human-landing catch method; outdoor and indoor captures were conducted simultaneously at each site for six hours. In the six sampled areas, we captured 2,185 mosquitoes belonging to seven Anopheles species. Of these specimens, 95.1% consisted of Anopheles darlingi, 1.8% An. triannulatus l.s., 1.7% An. deaneorum, 0.8% An. konderi l.s., 0.4 An. braziliensis, 0.1% An. albitarsis l.s., and 0.1% An. benarrochi. An. darlingi was the only species found in all localities; the remaining species occurred in sites with specific characteristics.

Biting behavior of Anopheles mosquitoes in Costa Marques, Rondonia, Brazil

Mosquito collections were made in and near Costa Marques, Rondonia, Brazil, to determine anopheline anthropophilic/zoophilic behavior. Collections from a non-illuminated, bovine-baited trap and indoor and outdoor human-bait collections were compared. Anopheles darlingi and Anopheles deaneorum were more anthropophilic than the other anophelines collected. The remainder of the Anopheles species were collected much morefrequently in bovine-baited traps than in human-bait collections. Anopheles darlingi and An. deaneorum were more frequently collected inside houses than the other anopheline species. But, when collections were made in a house with numerous openings in the walls, there were few differences in the percentages of each species biting man indoors versus outdoors. Anopheles darlingi was the predominant mosquito collected, both inside and outside houses, and had the strongest anthropophilic feeding behavior of the anophelines present.

Anopheles (Culicidae, Anophelinae) e a malária em Buriticupu-Santa Luzia, Pré-Amazônia maranhense

Neste trabalho, estudou-se as espécies do gênero Anopheles que se atraem por iscas humanas na Região de Buriticupu, Santa Luzia, Estado do Maranhão. Foram encontradas 7 espécies do subgênero Nyssorhyncus A. (N) darlingi, o principal vetor da malária humana na região, foi a espécie mais freqüente (53,1% da amostra total). Seguem na ordem de importância, A. (N) evansae (21.0%), A. (N) triannulatus (17.4%) e A. (N) nuñeztovari (4,8%). As demais espécies, A. (N) argyritarsis, A. (N) oswaldoi e A. (N) rangeli representaram juntas 3,7% da amostra total. As visitas foram mais frequentes no extra (51,7% da amostra total) do que no peridomicílio (45,7%). A. (N) darlingi e A. (N) evansae foram as únicas espécies encontradas no intradomicílio, numa proporção de aproximadamente 2,6% da amostra total. Os anofelinos ocorreram nas estações seca e chuvosa, com maior frequência na última, coincidindo com os elevados índices de caso de malária naquela região.

Malaria outbreaks in a non-endemic area of Brazil, 2005

In March 2005, a resident of the municipality of Monte Alegre de Minas, State of Minas Gerais, without any history of traveling to endemic areas for malaria, was diagnosed with Plasmodium vivax infection and local mosquito-borne transmission was suspected. The epidemiological investigation identified another 10 cases with local transmission and all of them were related to the imported malaria case that was detected in this region. The potential exposure site was the banks of the river Tejuco, an area frequented by mineral prospectors. Some of these prospectors were known to have come from states with malaria transmission. In the autochthonous cases, Plasmodium vivax and Plasmodium falciparum were diagnosed. Entomological investigation identified Anopheles (Nyssorhynchus) darlingi, Anopheles (Nyssorhynchus) albitarsis, Anopheles (Nyssorhynchus) triannulatus and Anopheles (Nyssorhynchus) parvus. After the first outbreak, another three autochthonous cases were notified in municipality of Monte Alegre de Minas, in the same year. The occurrence of these outbreaks highlights the importance of surveillance systems in areas that are nonendemic for malaria.

Encontro de larvas de Anopheles (Nyssorhynchus) argyritarsis em criadouros artificiais no Estado de Mato Grosso

Cita-se o encontro de formas imaturas de culicídeos em caixas d’água colocadas no nível do solo. Foram encontradas larvas de Anopheles argyritarsis e Aedes albopictus no município de Várzea Grande (MT). Considera-se que estes recipientes artificiais possam constituir locais adicionais utilizáveis como criadouros de anofelinos.

Ecologia de Anopheles (Nyssorhynchus) darlingi Root em área de implantação de empreendimento hidrelétrico, na divisa dos Estados do Mato Grosso do Sul e São Paulo

INTRODUÇÃO: Hidrelétricas alteram o fluxo das águas e provocam impactos sobre a composição de mosquitos, justificando-se essa pesquisa. O objetivo da pesquisa foi estudar anofelinos de área sob a influência de um novo lago e avaliar a vulnerabilidade relativa à malária. MÉTODOS: Foram feitas coletas de Anopheles nas margens da Represa Porto Primavera, durante as fases do alagamento até sua cota máxima. Utilizaram-se as técnicas: atrativa humana, de armadilha de Shannon e concha entomológica. Os indicadores Riqueza e Diversidade foram utilizados para medir o impacto. A análise das distribuições temporais foi realizada pelo teste Mann-Whitney, considerando localidade, cota e método de captura como variáveis independentes (α=0,05). RESULTADOS: A densidade de Anopheles darlingi oscilou entre as localidades A, B e C, sendo que os maiores picos foram para B e C. Com a estabilidade do lago, no último nível, evidenciou-se a tendência de redução da densidade de Anopheles darlingi. CONCLUSÕES: Sugere-se que o risco de autoctonia de malária nas proximidades do lago permanece inalterado, ficando o alerta para esporádicas infecções humanas.

Genetic variability among Anopheles species belonging to the Nyssorhynchus and Anopheles subgenera in the Amazon region

INTRODUCTION: Isoenzymatic analyses were performed involving species of the Nyssorhynchus and Anopheles subgenera in order to estimate the intra and interspecies genetic variability. METHODS: Mosquitoes were caught at different localities in the Amazon region. The collection and rearing of mosquitoes in the laboratory followed specific protocols. For the genetic variability analyses, the technique of horizontal electrophoresis on starch and starch-agarose gel with appropriate buffer systems was used. The alloenzyme variation was estimated using the Biosys-1 software. RESULTS: Out of the 13 loci, eight were polymorphic. Anopheles nuneztovari presented the largest number of alleles per locus, while the smallest number was detected in Anopheles marajoara from Macapá. The largest number of polymorphic loci was found for Anopheles marajoara from Maruanum and the smallest for Anopheles benarrochi (Guayará Mirim). Anopheles darlingi (Macapá) presented the greatest heterozygosity (Ho = 0.167 ± 0.071), while the lowest heterozygosity (Ho = 0.045 ± 0.019) was observed in Anopheles intermedius (Pacoval) of the subgenus Anopheles. Wright's F coefficient revealed considerable genetic structuring between the populations of Anopheles darlingi (Fst = 0.110) and between the populations of Anopheles marajoara (Fst = 0.082). CONCLUSIONS: Considering all the species studied, the genetic distance ranged from 0.008 to 1.114. The greatest distance was between Anopheles mattogrossensis and Anopheles oswaldoi, while the smallest was between the Anopheles benarrochi populations.

Larval control of Anopheles (Nyssorhinchus) darlingiusing granular formulation of Bacillus sphaericus in abandoned gold-miners excavation pools in the Brazilian Amazon Rainforest

INTRODUCTION: Use of a Bacillus sphaericus based mosquito larvicide was evaluated as an intervention for malaria vector control at a mining site in Amapá, Brazil. Impacts on larval and adult densities of the primary vector Anopheles darlingi were measured over the course of a 52 week study period.METHODS: In Calçoene, State of Amapá, gold mining activity occurs in 19 mining sites in gold-miners of Lourenço. Large pools are formed in mining sites and naturally colonized by Anopheles darlingi. During one year, the impact of applications of VectoLex(r) CG to these larval sources was evaluated. Applications of 20kg/ha were made as needed, based on 10 immature (3rd, 4th instars and pupae) surveillance of health and established thresholds. RESULTS: One hundred percent initial control was observed 48h after each treatment. The pools received from 2-10 (5.3±1.6) treatments during the year. The average re-treatment interval in productive pools was 9.4±4.3 weeks. During weeks 3-52 of the study, mean density of late stage larvae was 78% and pupae were 93% lower in the treated pools than in untreated pools (p< 0.0001, n=51) while reduction of adult mosquitoes was 53% in comparison to the untreated area during the last five months of the study, which were the rainy season (p<0.001).CONCLUSIONS:VectoLex(r) CG reduced immature Anopheles darlingi infestation levels during the entire study period, and reduced adult mosquito populations during the rainy season.

Larvicidal effects of endophytic and basidiomycete fungus extracts on Aedes and Anopheles larvae (Diptera, Culicidae)

Introduction In vitro bioassays were performed to access the larvicidal activity of crude extracts from the endophytic fungus Pestalotiopsis virgulata (Melanconiales, Amphisphaeriaceae) and the saprophytic fungus Pycnoporus sanguineus (Basidiomycetes, Polyporaceae) against the mosquitoes Aedes aegypti and Anopheles nuneztovari. Methods The extracts were tested at concentrations of 100, 200, 300, 400 and 500ppm. Ethyl acetate mycelia (EAM) extracts and liquid culture media (LCM) from Pe. virgulata and Py. sanguineus were tested against third instar larvae of Ae. aegypti and An. nuneztovari. Results The larvicidal activity of the EAM extracts from Pe. virgulata against Ae. aegypti had an LC50=101.8ppm, and the extract from the basidiomycete fungus Py. sanguineus had an LC50=156.8ppm against the Ae. aegypti larvae. The Pe. virgulata extract had an LC50=16.3ppm against the An. nuneztovari larvae, and the Py. sanguineus extract had an LC50=87.2ppm against these larvae. Conclusions These results highlight the larvicidal effect of EAM extracts from the endophyte Pe. virgulata against the two larval mosquitoes tested. Thus, Pe. virgulata and Py. sanguineus have the potential for the production of bioactive substances against larvae of these two tropical disease vectors, with An. nuneztovari being more susceptible to these extracts.

Parity and influence of abiotic factors on Anopheles in the Manso dam, State of Mato Grosso, Brazil

Introduction This study examined the parity of Anopheles mosquitoes and the influence of abiotic factors on the distribution of these mosquitoes in the Manso dam, Mato Grosso, Brazil. Methods The anophelines were captured using the Human Attraction Technique for 12 h, while recording the temperature and relative humidity. Parity was determined by examining the conditions of the filaments. Results Anopheles darlingi and Anopheles triannulatus accounted for 98.5% of the anophelines, with 88% of these being parous. Conclusions Sudden variations in weather could be the cause of shifts from the total absence of mosquitoes to the appearance of females in abundance over a three-day period.