ABSTRACT
Phylogenetic analysis of all 31 described mitochondrial (cytochrome b) haplotypes of Lutzomyia whitmani demostrated that new material from the State of Rondônia, in southwest Amazônia, forms a clade within a lineage found only in the rain-forest regions of Brazil. This rain-forest lineage also contains two other clades of haplotypes, one from eastern Amazônia and one from the Atlantic forest zone of northeast Brazil (including the type locality of the species in Ilhéus, State of Bahia). These findings do not favour recognizing two allopatric cryptic species of L. whitmani, one associated with the silvatic transmission of Leishmania shawi in southeast Amazônia and the other with the peridomestic transmission of Le. braziliensis in northeast Brazil. Instead, they suggest that there is (or has been in the recent past a continuum of inter-breeding populations of L. whitmani in the rain-forest regions of Brazil.
Subject(s)
Animals , Amazonian Ecosystem , Cytochromes b , DNA, Mitochondrial/ultrastructure , Phylogeny , Psychodidae/genetics , Disease Vectors , Leishmaniasis/epidemiology , Leishmaniasis/transmissionABSTRACT
Six species of Leishmania are at present known to cause cutaneous and/or mucocutaneous leishamniasis in Brazil, and they are all to be found in the Amazon region of this country. The eco-epidemiology of each is discussed, with the observation that the Amazonian leishmaniases are all zoonoses, with their source in silvatic mammals and phlebotomine sandfly vectors. With man's destruction of the natural forest in southern Brazil, some sandfly species have survived by adapting to a peridomestic or domiciliary habitat in rural areas. Some domestic animals, such as dogs and equines are seemingly now involved in the epidemiology of the disease. No such process has yet been reported in the Amazon region, but may well take place with the continuing devastation of its forest.
Subject(s)
Humans , Ecology , Leishmaniasis, Cutaneous/diagnosis , Animals, Laboratory/parasitology , Animals, Domestic/parasitology , Congress , Leishmaniasis, Visceral/diagnosisABSTRACT
Genomic DNA fragments from males of Psychodopygus wellcomei were isolated and shown to be useful as sensitive diagnostic probles for positively separting individuals of this species from those of Ps. complexus. These two members of the Ps. squamiventris series are found sympatrically in foci of cutaneous leishmaniasis in the hill forests of southern Pará State. Of the two species, only Ps. welcomei is thought to be an important vector of Leishmania braziliensis sensu stricto, buth this is based on circumstantial evidence because of the difficulties of identifying female sandflies wothin the series. The diagnostic probes were isolated from a library of Ps. wellcomei built by ligationg short fragments of Sau 3A-resistricted, genomic DNA into the plasmid vector PUC 18. Differential screening of 1316 library clones with total genomic DNA of Ps. Wellcomei and Ps. complexus identified 5 recombinants, with cross-hybridizing inserts of repetitive DNA, that showed strong specificity for Ps. wellcomei. As little as 0.4% of the DNA extracted from an individual sandfly (=ca. 0.5 namograms) was specifically detected. The diagnostic probes were used to identify as Ps. wellcomei a wild-caught female sandfly found infected with L. braziliensis s.s., providing only the second positive association between these two species
Subject(s)
Animals , Male , Female , DNA Probes , Psychodidae/genetics , Blotting, Southern , Disease Vectors , Genomic Library , Leishmania braziliensis/physiology , Leishmaniasis, Cutaneous/parasitology , Leishmaniasis, Cutaneous/transmissionABSTRACT
Fez-se registro, pela primeira vez, do isolamento de Leishmania (V.) lainsoni de um mamifero silvestre, o roedor Agouti paca (Rodentia: Dasyproctidae), no Estado do Para, Brasil. As amostras do parasita foram isoladas da pele, aparentemente integra, de 3 especimes desse roedor, capturados no municipio de Tucurui (ilha de Tocantins), em area que seria inundada pela formacao do lago da hidreletrica construida naquele municipio. Nenhum isolamento foi obtido de visceras de qualquer dos animais. A identificacao das amostras de L. (V.) lainsoni baseou-se na morfologia de amastigotas e promastigotas, no comportamento da infeccao em "hamsters", na analise bioquimica de isoenzimas e, ainda, atraves de testes com anticorpos monoclonais. A natureza inaparente da infeccao nos animais faz supor que o mamifero em questao possa representar um hospedeiro definitivo do parasita na regiao Amazonica.