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Biomedical subjects

D I Gibson

Publications and source records attributed to D I Gibson.

30 records · Page 2Linked to original sources
PubMed1997

Chaetotaxy and armature of Ichthyocotylurus erraticus (Rudolphi, 1809) and I. variegatus (Creplin, 1825) cercariae (Digenea, Strigeidae).

The armature and chaetotaxy of Ichthyocotylurus erraticus (Rudolphi 1809) and I. variegatus (Creplin 1825) cercariae were studied using scanning electron microscopy (SEM) and silver staining of the argentophilic sensilla. This represents the first detailed investigation of the surface structures of cercariae belonging to this genus. Both species exhibited a similar armature, although differences were recorded in the number of spines comprising the pre-oral tuft and the number of rows of spines in the post-oral collar. The number and the distribution of sensilla were found to be identical for both species of cercariae. Four types of sensilla, common to both species, were identified that differed in cilia length and in the structure of the surrounding collar. The distribution of particular sensillary forms was found to be consistent in both species.

Animals↗
PubMed1995

A study of the composition of the sclerites of Gyrodactylus Nordmann, 1832 (Monogenea) using X-ray elemental analysis.

The elemental compositions of the hamuli, marginal hooks and ventral bars were examined following their release from the opisthaptor of the monogenean parasites Gyrodactylus salaris, G. caledoniensis and G. colemanensis. Their compositions were determined using X-ray elemental analysis on an analytical scanning electron microscope, and the variation between each species investigated. Hamuli and marginal hooks exhibited a major peak for sulphur, whilst the ventral bar had high peaks of both sulphur and calcium. The high sulphur content and structure of the hamuli suggest they are composed of a keratin-like protein, while the nature of the ventral bar is less clear. The hamuli of G. colemanensis were differentiated from those of G. caledoniensis by virtue of their calcium fraction. Low levels of several other elements, including vanadium, were also detected in some sclerites. The composition of the hooks of Gyrodactylus and their relationship to the sclerites of monopisthocotyleans and polyopisthocotyleans is commented upon.

Animals↗
PubMed1994

The evolutionary expansion and host-parasite relationships of the Digenea.

Relevant data on the Digenea extracted from a host-parasite data-base are analysed in relation to host-groups, host-specificity, speciation, radiation and geographical distribution. The classification, evolution, co-evolution, and co-speciation of the group are discussed. Principal components analyses indicated that 119 families formed 11 groups in relation to their vertebrate hosts and the 55 families with molluscan records formed 6 groups in relation to their molluscan hosts. The most prominent host-groups are the Fish and Mammals. Individual digenean families did not exhibit the host combinations Fish+Birds, Fish+Mammals, Herpetiles+Birds and Herpetiles+Mammals. Families with Fish hosts tended to use Prosobranch and, to a lesser extent Bivalve, molluscs, whereas families in Herpetiles, Birds and Mammals tended to use Pulmonates. Families using 3 or 4 mixed vertebrate groups tended to use mixed molluscan groups. Families using Herpetiles as the vertebrate host tend to be the most host-specific and the least speciose, whereas those using 3 to 4 mixed vertebrate groups are the most speciose. In a detailed examination of three zoogonid genera, few indications of co-evolution with their vertebrate hosts were detected, and geographical information from the data-base appeared to shed no light upon the geographical origins of the Digenea. Some of these findings are commented upon in relation to the evolution of the Digenea.

Animals↗
PubMed1994

Molecular systematics in the acanthocephalan genus Echinorhynchus (sensu lato) in northern Europe.

New biological species and high levels of inter- and intraspecific genetic divergence were discovered in an allozyme study of some North European members of the acanthocephalan genus Echinorhynchus (sensu lato), parasites of fish and malacostracan crustaceans. (i) A strong differentiation between the marine E. gadi and the fresh- and brackish-water E. salmonis (genetic identity I congruent to 0) supports a generic distinction between these taxa; however, the subdivision would not entirely concur with the concepts of Echinorhynchus (sensu stricto) and Metechinorhynchus suggested earlier. (ii) Samples of E. gadi from the Baltic, Norwegian and North Seas included three distinct, partially sympatric biological species (spp. I-III; I congruent to 0.5). (iii) E. bothniensis, previously only known from the northern Baltic Sea, represents a complex of freshwater taxa with an intermediate host relationship to the 'glacial relict' Mysis spp. and with a distributional and host analogy to the North American E. leidyi. A population in a northern lake in the Barents Sea basin is closely related to E. bothniensis of the Baltic area, but is probably specifically distinct; the divergence between these populations (I congruent to 0.6) is similar to that between their Mysis host species. (iv) Considerable intraspecific differentiation (FST = 0.25), probably reflecting post-glacial population bottlenecks, was found between Baltic and nearby lacustrine E. bothniensis, and between Atlantic and Baltic E. gadi sp. I.

Acanthocephala↗
PubMed1989

Cutaneous oesophagostomiasis in man.

A case is presented of infection by Oesophagostomum, a nematode worm, producing a cutaneous nodule in man. Of the 70 individual cases reported in man it is believed that this is the first in which the worm has produced a lesion outside the gastro-intestinal tract and without evidence of bowel infection. This finding suggests either that the worm is able to achieve direct skin penetration or that it can be disseminated from the bowel via the bloodstream or the lymphatics. The pathology caused by Oesophagostomum and the possible modes of infection are discussed in relation to studies in animals, particularly simians and cattle.

Adolescent↗
PubMed1986

Gastro-intestinal helminths of donkeys in Burkina Faso.

Thirty adult donkeys from Burkina Faso were necropsied and their gastro-intestinal worm burdens counted and determined. The strongylids were the most abundant species with a prevalence of 100% for Strongylus vulgaris. Four species of Strongylus, two of Triodontophorus and six of the Cyathostominae were recovered. All of the animals were also infested with habronematid nematodes, but oxyurid and ascaridid nematodes were found in low numbers. In addition to the nematodes, the paramphistomid trematode Gastrodiscus aegyptiacus and the anoplocephalid cestode Anoplocephala magna occurred in varying numbers. Faecal egg-counts from 131 donkeys ranged between 100 and 9,200 for strongylid eggs.

Animals↗
PubMedDate not supplied

Hyperparasitism by helminths: new records of cestodes and nematodes in proteocephalid cestodes from South American siluriform fishes.

Proteocephalid cestode hyperparasites are reported from numerous proteocephalids occurring in pimelodid fishes in different regions of Brazil. In addition, three specimens of a nematode hyperparasite are reported from the proteocephalid cestode Choanoscolex abscissus from the pimelodid fish Pseudoplatystoma corruscans in Brazil. Previous records of cestode and nematode hyperparasites of cestodes are listed, and the possible identities of the Brazilian records are discussed.

Animals↗
PubMedDate not supplied

A survey of gastrointestinal helminths of the common helmet guinea fowl (Numida meleagris galeata) in Burkina Faso.

Guinea fowls in Burkina Faso (Africa) harbored 13 species of helminth parasites. The two most abundant species were Subulura suctoria and Ascaridia numidae, which comprised 89% of the nematodes. The other nematode species (Gongylonema congolense, Eucoleus annulatus, Synhimantus spiralis, Tetrameres fissispina, and Cyrnea parroti) occurred at low levels. Five species of cestodes and one acanthocephalan were also present. It is likely that guinea fowl act as important reservoir hosts of chicken nematodes.

Africa↗