Surto de leishmaniose cutânea americana na cidade de Tartagal, Província de Salta, Argentina, 1993

An American cutaneous leishmaniasis outbreak, with cases clustering during 1993 in Tartagal city, Salta, was reported. The outbreak involved 102 individuals, 43.1% of them with multiple ulcers. Age (mean: 33 years old) and sex distribution of cases (74.5% males), as well as working activity (70 forest-related), support the hypothesis of classical forest transmission leishmaniasis, despite the fact that the place of permanent residence was in periurban Tartagal. Moreover, during July, sandflies were only collected from one of the 'deforestation areas'. Lutzomyia intermedia was the single species of the 491 phlebotomines captured, reinforcing the vector incrimination of this species. Most infections must have been acquired during the fall (April to June), a pattern consistent with previous sandfly population dynamics data. Based on the epidemiological and entomological results, it was advised not to do any vector-targeted periurban control measures during July. Further studies should be done to assess if the high rate of multiple lesions was due to parasite factors or to infective vector density factors.Foi registrado um surto de leishmaniose cutânea americana, com casos agrupados na cidade de Tartagal, província de Salta, durante 1993. O surto envolveu 102 indivíduos, 43,1% deles com úlceras múltiplas. A idade (média: 33 anos) e distribuição de sexo nos casos (74,5% homens) como também a ocupação (70% relacionado com a floresta), apóia a hipótese da clássica transmissão de leishmaniose na floresta, apesar do fato de que o lugar de residência permanente estava na área periurbana de Tartagal. Além disso, durante julho, foram colecionados flebótomos só de uma área de desmatamento. Lutzomyia intermedia foi a única espécie dos 491 flebotomíneos capturados e reforça a incriminação de vetor desta espécie. A maioria das infecções deve ter sido adquirida durante o outono (abril para junho), um padrão consistente com dados prévios sob a dinâmica de população de flebótomos. Com base nos resultados, epidemiológicos e entomológicos foi aconselhado não fazer qualquer controle sobre vetores na área periurbana durante julho. Mais adiante deveriam ser feitos estudos para avaliar se a alta taxa de lesões múltiplas foi devido a fatores do parasita ou a fatores de densidade do vetor

Demographic history and population structure of Anopheles pseudopunctipennis in Argentina based on the mitochondrial COI gene

Background: Anopheles pseudopunctipennis is an important malaria vector in the Neotropical region and the only species involved in Plasmodium transmission in the Andean foothills. Its wide geographical distribution in America, high preference for biting humans and capacity to rest inside dwellings after feeding, are attributes contributing to its vector status. Previous reports have tried to elucidate its taxonomic status, distinguishing populations from North, Central and South America. In the present study we used a mitochondrial marker to examine the demographic history of An. pseudopunctipennis in northwestern Argentina. Methods: Twelve localities were selected across 550 km of the distribution of this species in Argentina, including two near the Bolivian border and several in South Tucumán, for sampling. A fragment of the cytochrome oxidase I (COI) gene was sequenced and haplotype relationships were analyzed by a statistical parsimony network and a Neighbor-Joining (NJ) tree. Genetic differentiation was estimated with FS T. Historical demographic processes were evaluated using diversity measures, neutrality tests and mismatch distribution. Results: Forty-one haplotypes were identified, of which haplotype A was the most common and widely distributed. Neither the network nor the NJ tree showed any geographic differentiation between northern and southern populations. Haplotype diversities, Tajima’s D T and Fu & Li’s F and D neutrality tests and mismatch distribution supported a scenario of Holocene demographic expansion. Conclusion: The demographic pattern suggests that An. pseudopunctipennis has undergone a single colonization process, and the ancestral haplotype is shared by specimens from all localities, indicating mitochondrial gene flow. Genetic differentiation was minimal, observed only between one northern and one southern locality. The estimated time of the population expansion of this species was during the Holocene. These data suggest that regional vector control measures would be equally effective in both northern and southern localities sampled, but also that insecticide resistant genes may spread rapidly within this region.Fil: Dantur Juri, Maria Julia. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto Superior de Entomología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Moreno, Marta. New York State Department of Health; Estados Unidos. State University Of New York; Estados Unidos. University Of California At San Diego; Estados UnidosFil: Prado Izaguirre, Mónica J.. Universidad Central de Venezuela; VenezuelaFil: Navarro, Juan C.. Universidad Central de Venezuela; VenezuelaFil: Zaidenberg, Mario O.. Ministerio de Salud de la Nación. Coordinación Nacional de Control de Vectores; ArgentinaFil: Almiron, Walter Ricardo. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Claps, Guillermo Luis. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto Superior de Entomología; ArgentinaFil: Conn, Jan E.. New York State Department of Health; Estados Unidos. State University Of New York; Estados Unido

American cutaneous leishmaniasis outbreak, Tartagal city, province of Salta, Argentina, 1993

An American cutaneous leishmaniasis outbreak, with cases clustering during 1993 in Tartagal city, Salta, was reported. The outbreak involved 102 individuals, 43.1% of them with multiple ulcers. Age (mean: 33 years old) and sex distribution of cases (74.5% males), as well as working activity (70 forest-related), support the hypothesis of classical forest transmission leishmaniasis, despite the fact that the place of permanent residence was in periurban Tartagal. Moreover, during July, sandflies were only collected from one of the 'deforestation areas'. Lutzomyia intermedia was the single species of the 491 phlebotomines captured, reinforcing the vector incrimination of this species. Most infections must have been acquired during the fall (April to June), a pattern consistent with previous sandfly population dynamics data. Based on the epidemiological and entomological results, it was advised not to do any vector-targeted periurban control measures during July. Further studies should be done to assess if the high rate of multiple lesions was due to parasite factors or to infective vector density factors