Validation of phlebotomine cardinal temperatures and humidities in the region of Rio Arinos, Mato Grosso, Brazil

The purpose of this study was to validate the phlebotomine cardinal temperatures and humidities, reported by Campelo Júnior et al. (2014), using different collection data, obtained in a study on the number of these insects, captured in the Arinos region, in Nova Mutum, Mato Grosso, Brazil, according to spatial (100 m to 1000 m) and temporal (June 2011 to April 2012) variability. Phlebotomines were captured in the riparian forest, by means of 10 traps positioned approximately every 100 m, northwards from the road along the river bank, with samples obtained bimonthly during three consecutive nights for a period of 12 months. Average relative humidity and temperature during the periods when the traps remained at the collection points were measured using a digital thermometer-hygrometer. The phlebotomine sand fly fauna was highly diversified, presenting 31 species, of which Lutzomyia antunesi was the most prevalent (45.4%). L. flaviscutellata, L. whitmani and L. umbratilis, known vectors of Leishmania spp., were also found. There was a marked variation in the quantity of phlebotomines captured throughout the consecutive collection days, as each sampling was affected by different factors determining a different maximum value for the number of insects present in each situation, as demonstrated for temperature and air humidity.

Phlebotomine sandfly fauna and natural Leishmania infection rates in a rural area of Cerrado (tropical savannah) in Nova Mutum, State of Mato Grosso in Brazil

Introduction American cutaneous leishmaniasis (ACL) has been reported in every municipality of the State of Mato Grosso, Brazil, but the transmission epidemiology remains poorly understood. Our study was developed in a rural area of the Nova Mutum municipality where four autochthonous cases of ACL were reported in 2009. Our aims were to describe the local phlebotomine sandfly fauna and to investigate the infection rates and infecting Leishmania species in the captured sandflies. Methods Entomological captures were performed bimonthly at 10 fixed sites close to the edge of a forested area between June 2011 and April 2012. Results A total of 3,743 phlebotomine sandflies belonging to 31 distinct species were captured. Approximately 75% of the specimens were females. The most abundant species (45.4%) was Lutzomyia antunesi, which was consistently captured at every site. Species that are epidemiologically important for ACL, such as L. flaviscutellata, L. whitmani and L. umbratilis, were also captured. L. antunesi and L. ubiquitalis were naturally infected by Leishmania braziliensis or Le. guyanensis, with minimum infection rates of 0.88% and 6.67%, respectively. Surprisingly, L. antunesi was infected by Le. infantum (synonym chagasi). Conclusions The natural infection of L. antunesi and L. ubiquitalis by Leishmania sp. suggests that these species might play a role in the zoonotic cycle of ACL in Nova Mutum. The presence of Le. infantum in L. antunesi suggests that there may be a risk of an outbreak of visceral leishmaniasis (VL) in Nova Mutum. .

Phlebotomine sand flies and canine infection in areas of human visceral leishmaniasis, Cuiabá, Mato Grosso / Flebotomíneos e infecção canina em áreas de leishmaniose visceral humana, Cuiabá, Mato Grosso

Visceral leishmaniasis is a systemic infectious disease that can cause to a severe, potentially life-threatening chronic condition in humans. Risk factors for infection in urban areas have been associated with poor living conditions, the presence of sand fly vectors and infected pets. This study aimed to describe sand fly and canine infection in the neighborhoods of human visceral leishmaniasis occurrence in the city of Cuiabá, Mato Grosso State, central-western Brazil, reported between January 2005 and December 2006. A total of 1,909 sand flies were collected. They were predominantly males and the most frequent species were Lutzomyia cruzi (81.25 percent), Lutzomyia whitmani (13.88 percent) and Lutzomyia longipalpis (2.62 percent). The sand fly density was not significantly correlated with the variation of environmental factors. The prevalence of canine visceral leishmaniasis in the neighborhoods studied was 26.82 percent and it was found that areas with high density of vectors coincided with areas of high prevalence of dogs and those with the highest rates of human cases. The study of vectors and other potential hosts are essential for a good understanding of visceral leishmaniasis and the related public health concerns, aiming at the prevention and control of leishmaniasis in the city of Cuiabá, Mato Grosso State.

A leishmaniose visceral é uma doença infecciosa sistêmica, de evolução crônica grave, potencialmente fatal para o homem. Os fatores de risco para a infecção em áreas urbanas têm sido associados às precárias condições de moradia, à presença de flebotomíneos vetores e de animais domésticos infectados. O presente trabalho objetivou descrever a fauna flebotomínica e infecção canina nos bairros de ocorrência da leishmaniose visceral humana no município de Cuiabá, Mato Grosso, notificados no período de janeiro de 2005 a dezembro de 2006. Foram coletados 1.909 flebotomíneos, as espécies mais frequentes foram Lutzomyia cruzi (81,25 por cento), Lutzomyia whitmani (13,88 por cento) e Lutzomyia longipalpis (2,62 por cento). A densidade de flebotomíneos não apresentou correlação significativa com a variação dos fatores ambientais. A prevalência de leishmaniose visceral canina nos bairros foi de 26,82 por cento e observou-se que as regiões com grande densidade de vetores coincidem com áreas de alta prevalência em cães e áreas nas quais foi detectado o maior número de casos humanos. O estudo de vetores e outros possíveis hospedeiros são imprescindíveis para um bom entendimento da doença a fim de gerar benefícios para a saúde pública, visando à prevenção e o controle das leishmanioses no município de Cuiabá e no Estado de Mato Grosso.

Temporal distribution of Aedes aegypti Linnaeus (Diptera, Culicidae), in a Hospital in Cuiabá, State of Mato Grosso, Brazil / Distribuição Temporal de Aedes aegypti Linnaeus (Diptera, Culicidae), em um Hospital de Cuiabá, Mato Grosso, Brasil

This study aimed at registering and monitoring the presence of Aedes aegypti in the University Hospital Júlio Muller, Cuiabá-MT, as well as investigating the influence of temperature and rainfall on its temporal distribution and egg densities in ovitraps. The study was performed from April/2007 to March/2008, utilizing ovitraps with 10 percent of hay infusion and a wood paddle as an oviposition substrate. For surveillance, one ovitrap was placed in each of the 12 points distributed throughout the hospital. Ovitraps were collected monthly at the end of a 5-day installation period. After egg counting, wood paddles were immersed in water to allow larval eclosion for species identification through optical microscopy. Egg Density Index (EDI), Positive Ovitraps Index (POI), and Mean Number of Eggs (MNE) were used for data analysis. The presence of A. aegypti in the hospital was registered throughout the study period, except in July. The MNE was proportionally higher in the internal area (n= 8.47 eggs/paddle) when compared to the external area (n= 5.46 eggs/paddle), and was higher in September/October 2007 and January/February 2008. A significant increase in EDI, POI and MNE was registered in periods where the average temperature was higher, and the increase in POI was also concomitant with an increase in rainfall. The continuous presence of A. aegypti in the hospital throughout the study period, points out the need of including this mosquito in the arthropod control list in this environment. This is particularly important, considering that A. aegypti is an important vector of several arboviroses.

Esse estudo objetivou registrar e monitorar a presença de Aedes aegypti no Hospital Universitário Júlio Muller, Cuiabá - MT, bem como investigar a influência da temperatura e pluviosidade sobre sua distribuição temporal e densidade de ovos em ovitrampas. O estudo foi realizado de abril/2007 a março/2008, usando ovitrampas com 10 por cento de infusão de gramínea e uma palheta de madeira como substrato para oviposição. Para o monitoramento, uma ovitrampa foi colocada em cada um dos doze pontos distribuídos nas dependências do hospital. Mensalmente, as armadilhas eram recolhidas ao final do quinto dia de instalação. Após a contagem dos ovos, as palhetas foram imersas em água para eclosão das larvas e identificação da espécie alvo em microscopia óptica. Índice de Densidade de Ovos (IDO), Índice de Positividade de Ovitrampas (IPO) e Número Médio de Ovos (NMO) foram usados para análise dos dados. A presença do mosquito no hospital foi registrada ao longo de todo experimento, exceto em julho. A densidade média de ovos foi proporcionalmente maior na área interna (n= 8,47 ovos/palheta) comparada à externa (n= 5,46 ovos/palheta). O NMO foi mais elevado nos meses de setembro e outubro de 2007, janeiro e fevereiro de 2008. Aumentos significativos do NMO, IPO e IDO, foram registrados com a elevação da temperatura, e no IPO com aumento da pluviosidade. A constante presença do mosquito A. aegypti no hospital, indica a necessidade de incluir esse mosquito na lista de controle de artrópodes nesse ambiente. Isso é particularmente importante, considerando que o A. aegypti é importante vetor de várias arboviroses.

Monitoramento do mosquito Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae), por meio de ovitrampas no Campus da Universidade Federal de Mato Grosso, Cuiabá, Estado de Mato Grosso / Monitoring of Aedes aegypti mosquitoes (Linnaeus, 1762) (Diptera: Culicidae) by means of ovitraps at the Universidade Federal de Mato Grosso Campus, Cuiabá, State of Mato Grosso

A dengue é uma das mais importantes arboviroses que atinge o homem e constitui um sério problema de saúde nas áreas tropicais, cujas condições climáticas são favoráveis à ocorrência de focos de Aedes aegypti. Armadilhas de oviposição acrescidas de infusão de feno foram instaladas em 19 pontos no Campus da Universidade Federal de Mato Grosso com o objetivo de verificar mensalmente o nível de infestação do vetor da dengue e a influência dos fatores abióticos. Os resultados obtidos foram comparados com dados abióticos de temperatura e umidade relativa do ar, e de precipitação pluviométrica, mensais e dos dias que as armadilhas permaneceram no campo. A chuva é o único fator abiótico que apresenta influência no nível de infestação dos vetores da dengue no local. Existem diferenças significativas entre as quantidades de ovos de Aedes aegypti encontrados em diferentes locais de coleta na mesma área de estudo. O número de ovos encontrados em cada ponto ao longo do ano não obedece a um padrão de distribuição único.

Dengue is one of the most important arboviruses affecting man and is a serious health problem in tropical areas where climatic conditions are favorable for occurrences of foci of Aedes aegypti. Oviposition traps with added hay infusion were installed at 19 points on the campus of the Federal University of Mato Grosso with the objective of investigating the monthly levels of infestation with the dengue vector and the influence of abiotic factors. The results obtained were compared with the following monthly abiotic data: temperature, relative air humidity and precipitation; and with the number of days for which the traps remained in the field. Rain was the only abiotic factor that influenced the level of infestation of the dengue vector at this location. There were significant differences between the quantities of Aedes aegypti eggs found at different sites within the same study area. The numbers of eggs found at each site over the year did not follow a single distribution pattern.