Malaria transmission in two localities in north-western Argentina

<p>Abstract</p> <p>Background</p> <p>Malaria is one of the most important tropical diseases that affects people globally. The influence of environmental conditions in the patterns of temporal distribution of malaria vectors and the disease has been studied in different countries. In the present study, ecological aspects of the malaria vector <it>Anopheles </it>(<it>Anopheles</it>) <it>pseudopunctipennis </it>and their relationship with climatic variables, as well as the seasonality of malaria cases, were studied in two localities, El Oculto and Aguas Blancas, in north-western Argentina.</p> <p>Methods</p> <p>The fluctuation of <it>An. pseudopunctipennis </it>and the malaria cases distribution was analysed with Random Effect Poisson Regression. This analysis takes into account the effect of each climatic variable on the abundance of both vector and malaria cases, giving as results predicted values named Incidence Rate Radio.</p> <p>Results</p> <p>The number of specimens collected in El Oculto and Aguas Blancas was 4224 (88.07%) and 572 (11.93%), respectively. In El Oculto no marked seasonality was found, different from Aguas Blancas, where high abundance was detected at the end of spring and the beginning of summer. The maximum mean temperature affected the <it>An. pseudopunctipennis </it>fluctuation in El Oculto and Aguas Blancas. When considering the relationship between the number of malaria cases and the climatic variables in El Oculto, maximum mean temperature and accumulated rainfall were significant, in contrast with Aguas Blancas, where mean temperature and humidity showed a closer relationship to the fluctuation in the disease.</p> <p>Conclusion</p> <p>The temporal distribution patterns of <it>An. pseudopunctipennis </it>vary in both localities, but spring appears as the season with better conditions for mosquito development. Maximum mean temperature was the most important variable in both localities. Malaria cases were influenced by the maximum mean temperature in El Oculto, while the mean temperature and humidity were significant in Aguas Blancas. In Aguas Blancas peaks of mosquito abundance and three months later, peaks of malaria cases were observed. The study reported here will help to increase knowledge about not only vectors and malaria seasonality but also their relationships with the climatic variables that influence their appearances and abundances.</p

The spatio-temporal distribution patterns of biting midges of the genus Culicoides in Salta Province, Argentina

The goal of this survey was to analyze the spatio-temporal distribution patterns of Culicoides Latreille species (Diptera: Ceratopogonidae) and their relationship with environmental variables in Salta, northwestern Argentina. Culicoides were collected monthly from January 2003 through December 2005. The influence of the climatic variables on population abundance was analyzed with a multilevel Poisson regression. A total of 918 specimens belonging to five species were collected. The most abundant species was Culicoides paraensis Goeldi (65.5%), followed by Culicoides lahillei Iches (14.6%) and Culicoides debilipalpis Lutz (7.6%). The highest seasonal abundance for C. paraensis, C. debilipalpis and C. lahillei occurred during the spring and summer. A Poisson regression analysis showed that the mean maximum and minimum temperature and the mean maximum and minimum humidity were the variables with the greatest influence on the population abundance of Culicoides species.Facultad de Ciencias Naturales y Muse

Potential Distribution Map of <i>Culicoides insignis</i> (Diptera: Ceratopogonidae), Vector of Bluetongue Virus, in Northwestern Argentina

Culicoides insignis Lutz is incriminated as a vector of bluetongue virus (BTV) to ruminants in America. In South America, almost all countries have serological evidence of BTV infections, but only four outbreaks of the disease have been reported. Although clinical diseases have never been cited in Argentina, viral activity has been detected in cattle. In this study, we developed a potential distribution map of Culicoides insignis populations in northwestern Argentina using Maximum Entropy Modeling (Maxent). For the analyses, information regarding both data of specimen collections between 2003 and 2013, and climatic and environmental variables was used. Variables selection was based on the ecological relevance in relation to Culicoides spp. biology and distribution in the area. The best Maxent model according to the Jackknife test included 53 C. insignis presence records and precipitation of the warmest quarter, altitude, and precipitation of the wettest month. Accuracy was evaluated by the area under the curve (AUC = 0.97). These results provide an important analytical resource of high potential for both the development of suitable control strategies and the assessment of disease transmission risk in the region.Facultad de Ciencias Agrarias y ForestalesFacultad de Ciencias Naturales y Muse

New Records of Biting Midges of the Genus Culicoides (Diptera: Ceratopogonidae) from the Yungas, Paranaense Rainforest and Chaco Ecoregions of Argentina

Culicoides insignis and C. venezuelensis are documented for the first time from Salta province, C. guttatus from Salta and Tucumán provinces, and C. austroparaensis, C. biestroi, C. fernandoi, and C. foxi from Misiones province. The geographical distributions of C. lahillei, C. brasilianum, C. dureti and C. pseudoheliconiae are extended to Chaco and Misiones provinces.Facultad de Ciencias Naturales y Muse

New Records of Biting Midges of the Genus Culicoides (Diptera: Ceratopogonidae) from the Yungas, Paranaense Rainforest and Chaco Ecoregions of Argentina

Culicoides insignis and C. venezuelensis are documented for the first time from Salta province, C. guttatus from Salta and Tucumán provinces, and C. austroparaensis, C. biestroi, C. fernandoi, and C. foxi from Misiones province. The geographical distributions of C. lahillei, C. brasilianum, C. dureti and C. pseudoheliconiae are extended to Chaco and Misiones provinces.Facultad de Ciencias Naturales y Muse

Latitudinal gradient of biting midges in the genus <i>Culicoides</i> (Diptera: Ceratopogonidae) in Argentina and Bolivia

We provide the first records of 8 species of biting midges in the genus Culicoides (Diptera: Ceratopogonidae) in a wide latitudinal gradient of the Yungas Ecoregion in Argentina and the Chaco Ecoregion in Bolivia, including a map of their distribution, and an updated checklist of species in the study area. Additional locality records were obtained from published articles and from specimens collected in these and other ecoregions in both countries. Included are the first Argentinean records of Culicoides crescentis Wirth & Blanton and C. pampaensis Spinelli & Wirth from Salta Province; C. caridei Brèthes, C. crescentis, C. guttatus Coquillett, C. insignis Lutz, C. pampaensis, and C. venezuelensis Ortiz & Mirsa from Jujuy Province, and C. saltaensis Spinelli & Wirth and C. pampaensis from Tucumán Province. In addition, the first records of C. brasilianum Forattini, C. crescentis, and C. guttatus are provided from Bolivia.Facultad de Ciencias Naturales y Muse

The spatio-temporal distribution patterns of biting midges of the genus Culicoides in Salta Province, Argentina

The goal of this survey was to analyze the spatio-temporal distribution patterns of Culicoides Latreille species (Diptera: Ceratopogonidae) and their relationship with environmental variables in Salta, northwestern Argentina. Culicoides were collected monthly from January 2003 through December 2005. The influence of the climatic variables on population abundance was analyzed with a multilevel Poisson regression. A total of 918 specimens belonging to five species were collected. The most abundant species was Culicoides paraensis Goeldi (65.5%), followed by Culicoides lahillei Iches (14.6%) and Culicoides debilipalpis Lutz (7.6%). The highest seasonal abundance for C. paraensis, C. debilipalpis and C. lahillei occurred during the spring and summer. A Poisson regression analysis showed that the mean maximum and minimum temperature and the mean maximum and minimum humidity were the variables with the greatest influence on the population abundance of Culicoides species.Facultad de Ciencias Naturales y Muse

Potential Distribution Map of <i>Culicoides insignis</i> (Diptera: Ceratopogonidae), Vector of Bluetongue Virus, in Northwestern Argentina

Culicoides insignis Lutz is incriminated as a vector of bluetongue virus (BTV) to ruminants in America. In South America, almost all countries have serological evidence of BTV infections, but only four outbreaks of the disease have been reported. Although clinical diseases have never been cited in Argentina, viral activity has been detected in cattle. In this study, we developed a potential distribution map of Culicoides insignis populations in northwestern Argentina using Maximum Entropy Modeling (Maxent). For the analyses, information regarding both data of specimen collections between 2003 and 2013, and climatic and environmental variables was used. Variables selection was based on the ecological relevance in relation to Culicoides spp. biology and distribution in the area. The best Maxent model according to the Jackknife test included 53 C. insignis presence records and precipitation of the warmest quarter, altitude, and precipitation of the wettest month. Accuracy was evaluated by the area under the curve (AUC = 0.97). These results provide an important analytical resource of high potential for both the development of suitable control strategies and the assessment of disease transmission risk in the region.Facultad de Ciencias Agrarias y ForestalesFacultad de Ciencias Naturales y Muse