Showing papers on "Digenea published in 1980"

Host specificity indices of parasites and their application.

Abstract: Indices are defined which describe host specificity of parasites but can be applied to any association between organisms. The indices are used to analyze latitudinal differences in host specificity of marine Monogenea and Digenea.

Ectoparasitic Monogenea, Digenea, and Copepoda from the gills of some marine fishes of New Caledonia and New Zealand

Abstract: The following ectoparasites are recorded from the gills of marine fishes in New Caledonia: Caligus prodiictus,’ Brachiella thynni (Copepoda), and Neothoracocotyle acanthocybii (Monogenea) from Acanthocybium solandri; Caligus productus, Caligus bonito (Copepoda), Allopseudaxinoides vagans, Allopseudaxine sp. (Monogenea), and Syncoelium filiferum (Digenea) from Katsuwonus pelamis. The following ectoparasites are recorded from the gills of marine fishes in New Zealand: Kahawaia truttae (Monogenea) and Syncoelium filiferum (Digenea) from Arripis trutta; Diplasiocotyle johnstoni (Monogenea) from Aldricheita forsteri; Neogrubea seriolellae, Eury‐sorchis australis (Monogenea), and Syncoelium filiferum (Digenea) from Seriolella brama; Mediavagina latridis (Monogenea), Lepeophtheirus erecsoni, and Aethon morelandi (Copepoda) from Latridopsis ciliaris. The male of Aethon morelandi is described for the first time.

A redescription of the fish blood-fluke Aporocotyle simplex Odhner, 1900 (Digenea, Sanguinicolidae) with comments on its biology

Abstract: The occurrence of A simplex in flatfish species at the type-locality, Gullmarfjorden on the west coast of Sweden, was studied A detailed morphological redescription and a specific diagnosis of the fluke is given Hippoglossoides platessoides is regarded as the main host and flukes from the co-hosts Limanda limanda and Pleuronectes platessa commonly show abnormal morphological features Morphological variations associated with host species and with size are described The possibility that the armed, extendable snout observed in living flukes may have been retained from the cercarial stage is suggested Ingestion of host blood cells is described and different functions of the two regions of the oesophagus in A simplex are discussed Pathological effects caused by dead, disintegrating flukes were observed in the gill filaments of the host The results presented make the status of A, orientalis Yamaouti, 1934, questionable and this species is regarded as a ‘species inquirenda’ A simplex of Zhuko

Studies on the biology of Plagiorchis elegans (Rudolphi, 1802), (Trematoda: Digenea) in its mammalian and molluscan hosts

Abstract: The taxonomy of the genus Plagiorchis Luhe, 1899 is reviewed with particular reference to the species P.elegans (Rud. 1802) and a list of Plagiorchia species previously recorded in Britain is given. The life cycle was initially established using Lymnaea stagnalis, Chironomus sp.larvae and LACA mice; morphology, intraspecific variation and host specificity at all levels of the life cycle have been examined and described. Besides L.stagnalis, L.palustris is susceptible to infection with P.elegans while L.peregra is refractory. Infections cause extensive damage to the digestive gland of L.stagnalis although they do not curtail its life span. Immature and mature specimens of L.stagnalis were infected; the former were castrated and the latter continued to reproduce. A single mother sporocyst of P.elegans produces approximately 650 daughter sporocyats from which develop several hundred thousand xiphidiocercariae. Upon release cercariae are negatively phototropic and negatively geotropic, with-light-and temperature affecting the rate of cercarial emmission. Cercariae encyst-in aquatic arthropods (Chironomus sp.,Asellus aquaticus and Gammarus pulex) and precociously in the snail host. Adult P.elegans range in size from 1.04 to 3.89mm by 0.34 to 0.96mm. Both mammals (mice, rats, gerbils and hamsters) and birds(chicks, ducklings and pigeons) are susceptible to infection. Egg counts were performed to follow the course of the infection in mice and rats. Primary infections of LACA mice are of short duration as a result of a host immune response. By means of surgical transplantation, the life span of P.elegans was increased from the expected 21 days to 63 days. Specimens recovered when the life cycle was completed using various combinations of intermediate and final hosts and those recovered from first and second challenge infections of LACA mice are compared statistically using canonical variate analysis. The only reliable anatomical criteria for distinguishing species of Plagiorchis are: 1. the relative sizes of the suckers and pharynx. 2. the presence or absence of a seminal receptacle, vas deferens and common genital atrium. 3. to a limited extent egg size and host specificity. According to these criteria many previously described species are considered to be synonymous with P.elegans and its geographical range is extensive.

On the morphological variation of Euparadistomum species (Digenea: Dicrocoeliidae) from small mammals in Malaysia.

Abstract: Euparadistomum is described from 7 species of small mammal in Malaysia. The worms display characteristics intermediate between E. buckleyi Singh and E. pearsoni Talbot particularly with regard to body shape and arrangement of vitelline fields. The nature of morphological variation is discussed and comment made on the possible life-cycle of the parasite.