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Biomedical subjects

D H Molyneux

Publications and source records attributed to D H Molyneux.

13 recordsLinked to original sources
PubMed1979

Studies on the ultrastructure, virus-like particles and infectivity of Leishmania hertigi.

Five strains of Leishmania hertigi hertigi isolated in Panama and three strains of L. hertigi deanei isolated in Brazil were studied. Ultrastructural examination of promastigotes grown in culture showed virus-like particles (VLPs), 55--60 nm diameter, in the cytoplasm of all strains. The VLPs were normally either organized in paracrystalline clusters or associated with induced tubules. In some cases the VLPs were associated with dense vesicular bodies. Mitochondria with which the VLPs were associated had enlarged elongate or circular cristae. Elongate 'microbodies' containing rod-like structures were observed in promastigotes grown in culture. Poor infections of promastigotes developed in the midguts of 10% of laboratory-bred Lu. longipalpis following experimental feeding on cultures of L. h. hertigi. VLPs were seen in a promastigote in the midgut of a sandfly five days after feeding. Laboratory mammals proved poor hosts for L. hertigi. Cryptic infections in the visceral organs of immunosuppressed hamsters and immunodeficient 'nude' mice were detectable only by culture. Infections of DS cell and mouse peritoneal macrophage cultures showed amastigotes with a high ribosomal density and deep invaginations of the pellicular layer. VLPs were rarely seen in these amastigotes.

Animals↗
PubMed1979

Tsetse movement in wind fields: possible epidemiological and entomological implications for trypanosomiasis and its control.

This paper presents evidence that tsetse flies (Glossina) can be dispersed by wind. This dispersal in West Africa is suggested to be along a south-west north-east axis. The implications of wind dispersal of Glossina for chemical and genetic control operations is discussed. Field experiments necessary to test this hypothesis are recommended. A study of human trypanosomiasis foci in West Africa has revealed that foci are orientated in roughly parallel lines in a south-west north-east direction. This directionally was significant when compared with 7 other compass points. It is proposed that foci could be populated by infected flies dispersed from the south west, where denser populations exist, on the prevailing winds in the late dry/early rainy season. The significance of these ideas in relation to the epidemiology of Trypanosoma brucei rhodesiense in Ethiopia and T. evansi are discussed.

Africa, Western↗
PubMed1978

Trypanosoma (megatrypanum) melophagium in the sheep ked, Melophagus ovinus. A scanning electron microscope (SEM) study of the parasites and the insect gut wall surfaces.

A description of the different stages of Trypanosoma (M.) melophagium in different regions of the gut of the sheep ked (Melophagus ovinus) as observed by the SEM is presented. The extensive pile carpet or palisade colonization of the midgut and pylorus is described. The method of attachment and the relationship of the parasites to the microvilli in the midgut and the cuticle of the pylorus and ileum observed by other methods are confirmed. The micro-structure of the surfaces themselves in the regions of the gut to which parasites attach are described. The use of the technique for the study of other similar systems is discussed.

Arachnid Vectors↗
PubMedDate not supplied

Observations on a trypanosomatid flagellate in a flea, Peromyscopsylla silvatica spectabilis.

The method of attachment of a trypanosomatid parasite to the cuticular epithelium of the hindgut of a flea Peromyscopsylla silvatica spectabilis by a desmosome-like structure is described; the flagella are modified and have enlarged intraflagellar areas which occupy the whole surface area of the gut, including clefts and folds of the epithelium. Unusual features of the parasite itself include a very much reduced flagellar pocket and pellicular microtubules which are made up of doublets and triplets. The problems of differentiation and characterisation of monogenetic insect flagellates are discussed in the light of these findings.

Animals↗