Rosina Djunko Miyazaki

Habitat suitability mapping of Anopheles darlingi in the surroundings of the Manso hydropower plant reservoir, Mato Grosso, Central Brazil

BackgroundHydropower plants provide more than 78 % of Brazils electricity generation, but the countrys reservoirs are potential new habitats for main vectors of malaria. In a case study in the surroundings of the Manso hydropower plant in Mato Grosso state, Central Brazil, habitat suitability of Anopheles darlingi was studied. Habitat profile was characterized by collecting environmental data. Remote sensing and GIS techniques were applied to extract additional spatial layers of land use, distance maps, and relief characteristics for spatial model building.ResultsLogistic regression analysis and ROC curves indicate significant relationships between the environment and presence of An. darlingi. Probabilities of presence strongly vary as a function of land cover and distance from the lake shoreline. Vector presence was associated with spatial proximity to reservoir and semi-deciduous forests followed by Cerrado woodland. Vector absence was associated with open vegetation formations such as grasslands and agricultural areas. We suppose that non-significant differences of vector incidences between rainy and dry seasons are associated with the availability of anthropogenic breeding habitat of the reservoir throughout the year.ConclusionSatellite image classification and multitemporal shoreline simulations through DEM-based GIS-analyses consist in a valuable tool for spatial modeling of A. darlingi habitats in the studied hydropower reservoir area. Vector presence is significantly increased in forested areas near reservoirs in bays protected from wind and wave action. Construction of new reservoirs under the tropical, sub-humid climatic conditions should therefore be accompanied by entomologic studies to predict the risk of malaria epidemics.

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

TDengue 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.

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.

Temporal distribution of Aedes aegypti Linnaeus (Diptera, Culicidae), in a Hospital in Cuiabá, State of Mato Grosso, Brazil

Esse estudo objetivou registrar e monitorar a presenca de Aedes aegypti no Hospital Universitario Julio Muller, Cuiaba - MT, bem como investigar a influencia da temperatura e pluviosidade sobre sua distribuicao temporal e densidade de ovos em ovitrampas. O estudo foi realizado de abril/2007 a marco/2008, usando ovitrampas com 10% de infusao de graminea e uma palheta de madeira como substrato para oviposicao. Para o monitoramento, uma ovitrampa foi colocada em cada um dos doze pontos distribuidos nas dependencias do hospital. Mensalmente, as armadilhas eram recolhidas ao final do quinto dia de instalacao. Apos a contagem dos ovos, as palhetas foram imersas em agua para eclosao das larvas e identificacao da especie alvo em microscopia optica. Indice de Densidade de Ovos (IDO), Indice de Positividade de Ovitrampas (IPO) e Numero Medio de Ovos (NMO) foram usados para analise dos dados. A presenca do mosquito no hospital foi registrada ao longo de todo experimento, exceto em julho. A densidade media de ovos foi proporcionalmente maior na area interna (n= 8,47 ovos/palheta) comparada a 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 elevacao da temperatura, e no IPO com aumento da pluviosidade. A constante presenca do mosquito A. aegypti no hospital, indica a necessidade de incluir esse mosquito na lista de controle de artropodes nesse ambiente. Isso e particularmente importante, considerando que o A. aegypti e importante vetor de varias arboviroses.

Phlebotomine sand flies and canine infection in areas of human visceral leishmaniasis, 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%), Lutzomyia whitmani (13.88%) and Lutzomyia longipalpis (2.62%). 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% 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.

Spatial and Temporal Abundance of Three Sylvatic Yellow Fever Vectors in the Influence Area of the Manso Hydroelectric Power Plant, Mato Grosso, Brazil

ABSTRACT Human biting catches of sylvatic yellow fever (SYF) vectors were conducted at eight stations in the influence area of the Manso hydroelectric power plant (Central Brazil) in sampling campaigns every 2 mo from July 2000 to November 2001. In total, 206 individuals were captured and classified as one of three species important for the transmission of SYF in Mato Grosso state: Haemagogus (Haemagogus) janthinomys (Dyar, 1921); Haemagogus (Conopostegus) leucocelaenus (Dyar & Shannon, 1924); and Sabethes (Sabethoides) chloropterus (Humboldt, 1819). The highest vector abundance was observed during the rainy season (November through March) and SYF vectors were present in all sampling points throughout the year, mainly in riparian and shadowed transitional forests at shadowed ramps.

Effective surveillance of vector dynamics of Aedes aegypti in a hospital setting in Cuiabá, Mato Grosso, Brazil

INTRODUCTION Hospitals are important for vector control of endemic diseases. METHODOLOGY To investigate the presence of dengue vectors, 30 locations at a university hospital in Cuiabá, Mato Grosso, Brazil, were monitored from January to December 2009 for mosquito eggs using ovitraps placed in high-traffic internal and external areas. RESULTS A total of 2,302 eggs were obtained. Positivity rate at different sites ranged from 50.0% to 0.0%, with the highest indices in external areas. The presence of eggs correlated with increasing humidity (r = 9.81; p = 0.0013). DISCUSSION The study aimed to detect and verify the infestation level of the dengue vector and the influence of abiotic factors. CONCLUSIONS The results indicate that this hospital may be considered an environment for the spread of dengue and hence strategic actions, including control measures and programs aimed at preventing the transmission of this vector, must be implemented.