241 resultados para vector field


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INTRODUCTION: Besides mosquito species adapted to urban environments (Culex quinquefasciatus, Aedes aegypti and Aedes albopictus), only 15 species of Anopheles had been recorded in the State of Pernambuco. METHODS: Human-landing mosquitoes were collected in Dois Irmãos Park, in Recife. RESULTS: The first report for the state of Haemagogus janthinomys, an important vector of yellow fever virus, and 14 other species, including Trichoprosopon lampropus, a first reported for Brazil. CONCLUSIONS: The mosquito fauna in the area is diversified and has potential medical and veterinary importance.

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The authors report the case of a female infant with Group III (or Grade III) megaesophagus secondary to vector-borne Chagas disease, resulting in severe malnutrition that reversed after surgery (Heller technique). The infant was then treated with the antiparasitic drug benznidazole, and the infection was cured, as demonstrated serologically and parasitologically. After follow-up of several years without evidence of disease, with satisfactory weight and height development, the patient had her first child at age 23, in whom serological tests for Chagas disease yielded negative results. Thirty years after the initial examination, the patient's electrocardiogram, echocardiogram, and chest radiography remained normal.

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INTRODUCTION: Leishmaniasis is an infectious and parasitic zoonotic, non-contagious, vector-borne disease caused by protozoa of the genus Leishmania. In Brazil, the major vector of Leishmania (Leishmania) infantum chagasi (Cunha & Chagas, 1934) is Lutzomyia longipalpis. Barra do Garças, State of Mato Grosso, was designated as a priority area by the Brazilian Ministry of Health for american visceral leishmaniasis, and it is important to identify the vector species present in this municipality. Our objective was to raise sandflies and study the influence of environmental variables on the vector density of Lutzomyia longipalpis. METHODS: We performed entomological monitoring in 3 districts using Centers for Disease Control and Prevention (CDC) light traps and recorded human cases of american visceral leishmaniasis in the city. We calculated the relative frequency and richness of sandflies and applied a transfer function model to the vector density correlate with relative humidity. RESULTS: The sandfly population was composed of 2 genera and 27 species, totaling 8,097 individuals. Monitoring identified Lutzomyia longipalpis (44%), followed by Lutzomyia lenti (18.9%), Lutzomyia whitmani (13.9%), Lutzomyia carmelinoi (9.1%), Lutzomyia evandroi (5.1%), Lutzomyia termitophila (3.3%), Lutzomyia sordellii (1.9%), and 20 other species (<4%). The male:female ratio was 3.5:1. We observed high species diversity (Dα = 6.65). Lutzomyia longipalpis showed occurrence peaks during the rainy season; there was a temporal correlation with humidity, but not with frequency or temperature. CONCLUSIONS: The presence of Lutzomyia longipalpis in the urban area of Barra do Garças underscores the changing disease profile, which was previously restricted to the wild environment.

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INTRODUCTION: Trypanosoma cruzi-infected specimens of Triatoma costalimai have been detected in domiciliary units of Central Brazil, thereby maintaining the potential risk of vectorial transmission of Chagas disease. The aim of this study was to determine the occurrence and natural infection of T. costalimai in different environments (gallery forest, dry forest and peridomicile) and climatic seasons (wet and dry), in the municipality of Mambaí, State of Goiás, Brazil. METHODS: Triatomines were captured in October 2010 and in June 2011, employing two different methods (manual capture and mouse-baited adhesive traps). The insects were later separated by sex and nymphal stage, counted and examined parasitologically by abdominal compression and microscopic analysis of feces. RESULTS: Triatoma costalimai was found in three environments and in the two seasons studied. Overall, capture success of 900 traps and 60 blocks of rocks inspected was 5.8% and 11.7%, respectively. The occurrence of T. costalimai was higher among rocks in the peridomicile, where 97% of the 131 specimens were captured. The proportion of nymphs (98%) was much higher than that of adults, which were only detected in peridomicile. Most (95%) insects were captured during the wet season, with predominance of early-stage nymphs. None of the 43 specimens examined were infected by trypanosomatids. CONCLUSIONS: The results indicate a greater occurrence of T. costalimai in peridomiciliary environments and during the wet season in Mambaí, Goiás, highlighting the synanthropic behavior of this triatomine species in one area of the Brazilian savanna and the importance of entomological surveillance.

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INTRODUCTION: The aim of the present study was to analyze the larvicidal activity of different crude extracts of Larrea cuneifolia and its most abundant lignan, nordihydroguaiaretic acid (NDGA), against Culex quinquefasciatus. METHODS: Chloroform, methanol, and aqueous extracts from L. cuneifolia and NDGA were tested against larvae of Cx. quinquefasciatus under laboratory conditions. RESULTS: The chloroform extract showed the highest larvicidal effect, with an estimated LC50 of 0.062 mg/ml. NDGA also demonstrated significant larvicidal activity with an estimated LC50 of 0.092 mg/ml. CONCLUSIONS: These results indicate that the chloroform extract of L. cuneifolia and NDGA are promising insecticides of botanical origin that could be useful for controlling Cx. quinquefasciatus.

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Introduction This work aimed to analyze the triatomine infestation scenario in Jaboticatubas after 30 years of the uninterrupted actions of the Program of Chagas Disease Control. Methods From 2007 to 2010, household unit infestation was researched, and an exploratory analysis of the localities infested with Panstrongylus megistus was performed. Results In total, 613 triatomines were captured in 78 households, the majority of which were Panstrongylus megistus and were captured mainly in chicken houses, but they were also found to be colonizing human houses. Conclusions The epidemiological importance of Panstrongylus megistus was confirmed in Jaboticatubas, and capability to colonize indoors has been demonstrated, as has its proximity to humans. Its distribution is aggregated in the northern and in central-eastern regions of the municipality.

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Introduction Triatoma sordida is the most captured Triatomine species in the Brazilian artificial environment. In 2008, the discovery of three Triatomine populations with altered susceptibilities to deltamethrin highlighted the importance of investigating the genetic potential for resistance in triatomines. The purpose of this study was to characterize the susceptibility to deltamethrin of peridomestic T. sordida populations in Minas Gerais, Brazil. Methods A susceptibility reference lineage derived from Uberaba, Minas Gerais, Brazil was used. Serial dilutions of deltamethrin were prepared and applied to the dorsal abdomen of first instar nymphs. The control group received only pure acetone. Mortality was evaluated after 72h. Qualitative tests assessed mortality in response to a diagnostic dose of 1xLD99 of the susceptibility reference lineage. Results Susceptibility profile characterization of T. sordida populations revealed resistance ratios (RR50s) ranging from 0.42 to 3.94. The percentage mortality in response to the diagnostic dose varied from 70% to 100%. A comparison of the results obtained in the quantitative and qualitative assays demonstrated a lack of correspondence for some populations. Conclusions We demonstrated that only T. sordida populations that present a RR50>1.0 have altered susceptibility, and the execution of simultaneous field and laboratory tests is required to understand the actual effect of vector control. A possible cause of the observed resistance ratios might be the continuous use of pyrethroids in Brazil since the 1980s.

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Introduction Trypanosoma evansi was first identified in the Canary Islands in 1997, and is still present in a small area of the Archipelago. To date, the disease has exclusively affected camel herds, and has not been detected in any other animal hosts. However potential vectors of Trypanosoma evansi must be identified. Methods One Nzi trap was placed on a camel farm located in the infected area for a period of one year. Results Two thousand five hundred and five insects were trapped, of which Stomoxys calcitrans was the sole hematophagous vector captured. Conclusions Stomoxys calcitrans could be exclusively responsible for the transmission of Trypanosoma evansi among camels in the surveyed area, as other species do not seem to be infected by S. calcitrans in the presence of camels.

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IntroductionThe larvicidal activity of Solanum lycocarpumagainst Culex quinquefasciatus is unknown.MethodsWe evaluated the larvicidal activity of extracts of the green fruits of Solanum lycocarpum against third and fourth instar larvae of C. quinquefasciatus.ResultsDichloromethane and ethyl acetate fractions showed the greatest larvicidal effect at 200mg/L (83.3% and 86.7%, respectively). The methanol and dichloromethane, ethyl acetate, and hydromethanolic fractions demonstrated larvicidal effects against C. quinquefasciatus, with LC50 values of 126.24, 75.13, 83.15, and 207.05mg/L, respectively.ConclusionsThus, when considering new drugs with larvicidal activity from natural products, S. lycocarpum fruits may be good candidate sources.

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Introduction This study evaluated the presence of pathogenic human parasites on field-grown strawberries in the Federal District of Brazil. Methods A total of 48 samples of strawberries and 48 soil samples from 16 properties were analyzed. Results Contaminated strawberries were detected in 56% of the properties. Schistosoma mansoni, Ascaris lumbricoides or Ascaris suum, Balantidium coli, Endolimax nana, and Entamoeba spp. were detected. Soil was contaminated with Entamoeba spp., Entamoeba coli, Strongyloides spp., Ancylostomatidae, and Hymenolepis nana. Conclusions Producers should be instructed on the safe handling of strawberries in order to reduce the incidence of strawberries that are contaminated with enteroparasites.

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INTRODUCTION: Visceral leishmaniasis (VL) is a zoonosis of great importance to public health and is considered a neglected disease by the World Health Organization. The disease has expanded and become more prevalent in urban areas in Brazil. METHODS: Geospatial analyses were performed and thematic maps of the triad of the disease were produced for the study period (2003-2012) in the urban area of the municipality of Rondonópolis in the midwestern State of Mato Grosso (MT), Brazil, TerraView 4.2.2 software was used for the analyses. RESULTS: A total of 87.9% of the 186 confirmed human cases of VL were cured. Children between the ages of 1 and 4 were the most affected. Registered deaths were predominant among adults aged 60 years or older. The urban area of the municipality consists of eight strata and 12 census districts include 237 neighborhoods. All sectors had confirmed cases of VL. During the study period, human cases of the disease were recorded in 90 neighborhoods. The 23 deaths from the disease were distributed in 21 neighborhoods. Sandflies carrying the parasite were captured in 192 out of 200 neighborhoods evaluated for the presence of the VL vector. The presence of dogs carrying the parasite was confirmed in, 140 out of 154 surveyed neighborhoods. CONCLUSIONS: The data demonstrated the endemic nature of VL, with a high percentage of infected children, a high distribution of canine infection, and a wide adaptation and dispersal of the vectors in the urban environment. These results, illustrate the process of urbanization of VL in the municipality of Rondonópolis, MT, Brazil.

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Abstract:INTRODUCTION:Despite the recommendations by interpretation of resistance ratios obtained in laboratory bioassays, little is known about the actual impact of these results in the effectiveness of vector control activities in the field. In this context, our objective was to determine the mean value of different resistance ratios obtained by laboratory bioassays performed as part of the chemical control strategies of Triatoma sordida in the field.METHODS:Field bioassays were developed in Monte Azul and Coração de Jesus (Southeast, Brazil). In each location, samples were formed with three domestic units treated with alpha-cypermethrin 20.0% (Alfatek (r) 200 SC). One day after spraying, 10 fifth-instar nymphs remained in contact with the surfaces treated (adobe with plaster, adobe without plaster, or wood) with insecticide in plastic cones for 72h. Three cones were exposed inside the intradomicile and the peridomicile. The insects in the control group were exposed to an insecticide-free piece of cardboard. Mortality was measured 72h after removal of the insects from the treated surfaces. The tests were realized in triplicate.RESULTS:Mortality was 100.0% in all locations, except for Monte Azul; Landinho (96.6%) and Coração de Jesus; Barriguda (96.6%).CONCLUSIONS:Although the resistant populations in laboratory tests proved to be susceptible in the field, this observation is not sufficient to suggest that the cut-off points used to justify the resistance ratio should be changed. In this sense, we recommend that laboratory and field bioassays are carried out with a greater number of Triatominae populations to allow more in-depth consideration of the subject.

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ABSTRACTINTRODUCTION:The larvicidal activity of oils, fatty acids, and methyl esters of Solanum lycocarpum fruit against Culex quinquefasciatus is unknown.METHODS:The larvicidal activity of samples of ripe and unripe fruit from S. lycocarpum was evaluated against third and fourth instar larvae of C. quinquefasciatus .RESULTS:The oils, fatty acids, and methyl esters of S. lycocarpum showed the greatest larvicidal effect (57.1-95.0%) at a concentration of 100mg/L (LC 50values between 0.70 and 27.54mg/L).CONCLUSIONS:Solanum lycocarpum fruit may be a good source of new natural products with larvicidal activity.

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ABSTRACT INTRODUCTION: Aedes aegypti eggs can be collected from the water surface. METHODS: Aedes aegypti oviposition from 97 field ovitraps was studied. RESULTS: Of the 16,016 eggs collected, 11,439 were obtained from paddles in ovitraps and 4,577 from water. Further, 89 (91.8%) traps contained eggs on water and 22 (22.7%) traps contained eggs only on water. CONCLUSIONS: In field traps, Aedes aegypti females usually oviposit some eggs on water surface suggesting that they might also oviposit on water of some natural breeding, and this possibility needs to be investigated. Eggs oviposited on water need to be considered for collecting trap data.