A Mitochondrial DNA phylogeny indicates close relationships between populations of Lutzomyia whitmani (Diptera: Psychodidae, Phlebotominae) from the rain-forest resgions of Amazônia and Northeast Brazil

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.

Cytological and isoenzyme analysis of the Bucay and Quevedo cytotypes of the onchocerciasis vector Simulium exiguum (Diptera: Simuliidae) in Ecuador

Four cytotypes of Simulium exiguum occur in Ecuador, where this morphospecies is the primary vector of onchocerciasis. In this paper, we give the first full description of the banding pattern of the larval polytene chromosomes of the Quevedo cytotypes differ from the chromosomal standard sequence (of the Cayapa cytotype) by the fixed inversions IIL-5 and IIL-6. The Quevedo cytotype additionally differs from the standard and Bucay cytotypes by processing a differentiated X chromosome, wich is indicated by the inversion IIS-A. As the degree of reproductive isolation between the Bucay and Quevedo cytotypes has not yet been estabilished, they must be regarded as intraspecific variants of the same species. In fact, isoenzyme characterizations showed that the Bucay and Quevedo cytotypes are differentiated only to the extent expected of incipient species or geographical populations. Moreover, the sibiling species status previously given to the Bucay cytotype needs be reassessed, there being inadequate analysis from areas in Ecuador where Bucay occurs in sympatry with the standard Cayapa cytotype. No isoenzyme electromorphs were discovered that identified all or mostadult females of any one (cytotype-pure) collection

DNA probes for distinguishing Psychodopygus wellcomei from Psychodopygus complexus (Diptera: Psychodidae)

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

A pilot study to control Lutzomyia umbratilis (Diptera: Psychodidae), the Leishmania brazileiensis greyanensis, in a peri-urban rainforest of Manaus, Amazonas State, Brazil

No segundo semestre de 1980, 112 (ou aproximadamente 16%) dos habitantes do recém estabelecido bairro de Säo José, cidade de Manaus, contraíram leishmaniose, durante o desmatamento que realizavam em seus lotes localizados na floresta tipo "terra firme". Com a ajuda da SUCAM, os AA. realizaram um estudo piloto para investigar a viabilidade de reduçäo das populaçöes de Lutzomyia umbratilis, o vetor silvático de Leishmania braziliensis guyanensis, borrifando inseticidas na base das árvores grandes da floresta que säo os lugares preferidos de repouso diurno destes insetos. A maioria do contato homem-vetor ocorre nestes lugares de repouso diurno (o vetor sendo mais ativo à noite nas copas das árvores) e, assim sendo, foi animador constatar uma nítida reduçäo das populaçöes de L. umbratilis nas bases das árvores por um período de 21 dias após uma única aplicaçäo de emulsäo de D.D.T. numa área de 200m quadrados. Quantidade apreciável de D.D.T. permaneceu na base das árvores por pelo menos oito meses, o que proporcionou a näo ocupaçäo das mesmas por L. umbratilis durante pelo menos onze meses. Os resultados mostram que a emulsäo de D.D.T. teve efeito repelente e letal(L. umbratilis foi altamente suscetível ao D.D.T. em "kits" da O.M.S.). Em contraste com as populaçöes das bases das árvores, as populaçöes noturnas de L. umbratilis (capturadas em armadilhas de luz tipo CDC, ou atacando ao homem näo foram significantemente reduzidas pelo tratamento com D.D.T., o que sugere a possível existência de apreciável imigraçäo noturna em áreas experimentais e/ou que lugares de repouso alternativo tenham sido procurados pelos flebótomos. Säo apresentadas sugestöes para ampliar o estudo piloto e a necessidade de colaboraçäo com uma equipe clínica é enfatizada. A leishmania b. guyanensis é o agente etiológico de uma forma de leishmaniose tegumentar humana ("pian bos") hiperendêmica numa vasta extensäo geográfica que se estende da Guiana Francesa à Amzônia Central, ao Norte do Rio Amazonas. Na ausência de uma vacina comprovada ou de métodos eficientes de controle do vetor, alguns métodos simples säo oferecidos para limitar a transmissäo de Le. b. guyanensis ao homem

Presence of Psychodopygus wellcomei (Diptera: Psychodidae), a proven vector of Leishmania braziliensis braziliensis, in Ceara State.

Psychodopygus wellcomei, um vetor comprovado de leishmaniose (muco) cutanea, foi pela primeria vez encontrado fora da Bacia Amazonica, no Estado do Ceara. Evidencia parasitologica e entomologica sugere que a Leishmania braziliensis braziliensis transmitida pelo Ps. wellcomei encontra-se largamente espalhada no "Macico montanhoso do Brasil"