Search PubMed⌕ Search

Biomedical subjects

J J Shaw

Publications and source records attributed to J J Shaw.

154 records · Page 9Linked to original sources
PubMedDate not supplied

The transmission of suprapylarian leishmania by the bite of experimentally infected sand flies (Diptera: Psychodidae).

Lutzomyia furcata transmitted Leishmania chagasi to a hamster 10 days after being experimentally fed on an infected spleen. An individual female Psychodopygus carrerai carrerai that had fed on a hamster lesion caused by Leishmania mexicana amazonensis transmitted this parasite 6 days later to another hamster. Transmission electron microscopy of this fly's head revealed a small number of degenerate promastigotes in the foregut, but only a few were attached.

Animals↗
PubMedDate not supplied

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 probes for positively separating 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. wellcomei is thought to be an important vector of Leishmania braziliensis sensu stricto, but this is based on circumstantial evidence because of the difficulties of identifying female sandflies within the series. The diagnostic probes were isolated from a library of Ps. wellcomei built by ligating short fragments of Sau 3A-restricted, 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 nanograms) 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.

Animals↗
PubMedDate not supplied

The dermal leishmaniases of Brazil, with special reference to the eco-epidemiology of the disease in Amazonia.

Six species of Leishmania are at present known to cause cutaneous and/or mucocutaneous leishmaniasis 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.

Animals↗
PubMedDate not supplied

Taxonomy of the genus Leishmania: present and future trends and their implications.

The application of different taxonomic methods (Cladistic, Evolutionary Taxonomy and Numerical Taxonomy) to the taxonomy of the Genus Leishmania are reviewed. The major groupings of the most recent classifications obtained using the cladistical approach agree with the major divisions of previous classifications which used traditional taxonomy (Evolutionary Taxonomy). The advantage of the cladistical approach is that it produces cladograms whose branches indicate more accurately levels of relationships between the different taxa. Numerical Taxonomy is useful for identification but not as good as the cladistical approach for classification. The ancient division of this monophyletic genus into two major evolutionary lines supports the use of the subgeneric names Leishmania and Viannia.

Animals↗
PubMedDate not supplied

A mitochondrial DNA phylogeny indicates close relationships between populations of Lutzomyia whitmani (Diptera: Psychodidae, Phlebotominae) from the rain-forest regions of Amazônia and northeast Brazil.

Phylogenetic analysis of all 31 described mitochondrial (cytochrome b) haplotypes of Lutzomyia whitmani demonstrated 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.

Animals↗