Ecology of Sand Flies (Diptera: Psychodidae: Phlebotominae) in the North of the State of Mato Grosso, Brazil

Abstract

Key words: Lutzomyia umbratilis -Leishmania braziliensis -Phlebotominae -Mato Grosso -Brazil Environmental alterations in different regions of Brazil have been modifying the epidemiological profile of leishmaniasis for some decades. These changes have created high-risk areas for Leishmania infection (Lainson 1988, 1989, Walsh et al. 1993, Rangel 1995.The migration movements toward the Amazon Region that have taken place in the last three decades have been directly or indirectly supported by the Federal Government through colonization projects and road construction. Those migratory currents have produced considerable alterations in the environment and they have given rise to haphazard colonization models. Such environmental changes and new associations between man and nature have created new focuses of human disease: malaria and, especially of cutaneous leishmaniasis. Peixoto de Azevedo country, in the north of the State of Mato Grosso, is an area where such a chain of events has been recorded.The region was covered by primitive forest 25 years ago, but now there are over 100,000 inhabitants in the area, and their main interests have been agriculture and mining. These two activities account for the regions thriving economy followed by wood extraction and cattle raising. The economic development of the region has contributed to the changing in the environment and has brought the population into contact with vector sand flies and could explain the increase in the number of cases of (T Pereira, pers. commun.).This study aims to contribute to present knowledge on phlebotomine sand fly ecology the in the Central-West Region of Brazil. MATERIALS AND METHODSArea studied -Peixoto de Azevedo, a large country covering an area of 14,383 km 2 is located 661 km from Cuiabá, in the north of the State of Mato Grosso, at latitude 10 o 13'23"S and longitude 54 o 58'47"W (Fig. 1). The weather is hot and humid, with three dry months (equatorial climate), with an average yearly temperature of 26 o C, and annual rainfall ranging from 2,000 to 3,000 mm. The relief of the area presents a complex base made up of southern Amazon Plateau Residuals. Those plateaus, that interfluves with slopes at heights above 400 m are included in the Peripheral Amazon Basin, which also features mountain ridges carved in volcanic, sub-volcanic and metamorphic Precambrian rocks. The local vegetation is composed by an ecologically tense region, a small spot where two different vegetation types occur (Ama- zon Forest and savanna) (IBGE 1996). This region has been influenciated by human modifications (anthropic action). The local economy now is based on agricultural production (rice, corn, beans), cattle raising, timber extraction (cinnamon, jatobá and cedar), and lately, in less proportion on gold prospecting.Sand fly collections -In order to establish the two collection sites, some captures with Shannon trap were done. The station Beira-Rio Farm was approximately 22 km apart from station BR-080 (primary Forest). Sand fly collections were carried out mo...

Phlebotomines (Diptera: Psychodidae) in forested areas of the Serra da Bodoquena, state of Mato Grosso do Sul, Brazil

“…On the other hand, this density (i.e., of 2.4 insects/trap) is much lower than that observed in the Amazon forest in the northern region of Mato Grosso (ca. 60.0 insects/trap in preserved and degraded areas) (Azevedo et al 2002). It is also much inferior to that obtained in the 12 caves sampled on the Serra da Bodoquena (62.8 insects/trap) (Galati et al 2003a).…”

Study on phlebotomine sand fly (Diptera: Psychodidae) fauna in Belo Horizonte, state of Minas Gerais, Brazil

“…Previous investigations have proven that the single use of CDC traps does not allow the identification of phlebotomine fauna concerning its quantitative and qualitative features (Azevedo et al 2002, Oliveira et al 2003. Based on the results of the current work, the use of Shannon traps allowed us to evaluate the presence of some species that were not collected (Passos et al 1993) and it has been shown to be highly sensitive in detecting protozoa parasites into phlebotomine sand flies (Rodriguez et al 1999, Miranda et al 2002, Michalsky et al 2002.…”

“…Due to this fact, several studies have been undertaken in order to better understand the biology of L. whitmani. Particular features regarding genetics and adaptation of the species allow it to have different feeding and behavioral habits, depending on the habitat they live in (Rangel et al 1996, CampbellLedrum et al 2000, Azevedo et al 2002, Margonari et al 2004. Upon collecting L. whitmani in BH, it could be observed that the species is present in peridomiciliary areas as well as inside the houses (Tables IV, V), besides being predominant in thickly forested areas (Table V).…”

“…Nowadays, leishmaniasis has been observed in large urban centers, showing a wide diversity and adaptation of parasites (Leishmania) and vectors to the environmental changes caused by man (Marzorchi & Marzorchi 1994, Ashford 2000, Travi et al 2002, Azevedo et al 2002. Such factors enable the existence of several clinic-epidemiological manifestations of the disease and make control measures difficult in those areas.…”

Distribuição geográfica e características epidemiológicas da leishmaniose tegumentar americana em áreas de colonização antiga do Estado do Paraná, Sul do Brasil

“…Esse fato fica claro quando se nota que a grande maioria dos indivíduos nessa situação é do sexo masculino em idade produtiva, com residência permanente na zona urbana dos municípios paranaenses. A migração para a Região Amazônica nas últimas décadas, apoiada direta ou indiretamente pelo governo federal por meio de projetos desorganizados de colonização e construção de estradas, é um fator interveniente importante na ocorrência da leishmaniose tegumentar americana 30 . Em muitos casos os migrantes não se adaptam bem, devido ao novo sistema agrícola vigente e pela perda dos laços familiares e comunitários, retornando à sua origem.…”