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At least 811 records · Page 45Linked to original sources
PubMed1996

On the distribution and abundance of eel parasites in Nova Scotia: influence of pH.

The geographic distribution of metazoan parasites of American eels (Anguilla rostrata) was determined from 28 sites in the Southern Upland and adjacent regions of Nova Scotia. Twelve parasite species were encountered. Component community diversity as measured by species richness, Shannon-Wiener index (H') and Hill's number (N1) decreased when pH < 5.4. Seven species (Azygia longa, Crepidostomum brevivitellum, Bothriocephalus claviceps, Proteocephalus macrocephalus, Paraquimperia tenerrima, Echinorhynchus salmonis, Ergasilus celestis) were found in both the Southern Upland and adjacent watersheds to the north. Three species (Pseudodactylogyrus anguillae, Diplostomum sp., Pomphorhynchus bulbocolli) were found only at sites beyond the Southern Upland, which flowed into the Bay of Fundy and had high pH values ( > 5.4). Two species (Daniconema anguillae, Echinorhynchus lateralis) were limited to sites within the Southern Upland. Digeneans were absent from rivers in the southwest with pH values < 4.7. Variation in occurrence of parasite species was observed among rivers within a single watershed and among years within individual sites. Nevertheless, the impact of acidity at the local level was observed regionally across the Southern Upland of Nova Scotia. These data support the hypothesis that parasite assemblages may be good indicators of environmental stress.

Acanthocephala↗
PubMed1997

Intestinal helminths of river otters (Lutra canadensis) from the Pacific northwest.

The intestinal helminth fauna of river otters, Lutra canadensis, from the Pacific Northwest was characterized by low species richness and intensity of infection. River otters from the lower Columbia River (n = 23) were infected with 9 species of helminths (83% prevalence); those from a relatively undisturbed reference area near the headwaters of the Trask and Wilson rivers on the Oregon coast (n = 6) were infected by 5 species of helminths (100% prevalence). Single species of Eucestoda (Schistocephalus solidus), Digenea (Euparyphium inerme), Acanthocephala (Corynosoma strumosum), and 8 species of Nematoda (Strongyloides lutrae; larvae of Eustrongylides sp., Anisakis sp., and Contracaecum sp.; 3 of Cystidicolidae, and Hedruris sp.) were collected. Most species are typical of piscine definitive hosts and were present as incidental parasites of river otters. Notably, specimens of Euparyphium inerme are reported for the first time in river otters from North America; occurrence of other helminths constitutes new host or geographic records for parasites in river otters in Oregon and Washington. Parasites with marine life cycles were acquired by river otters in freshwater habitats at a great distance from the ocean. The helminth fauna of river otters in the Pacific Northwest was influenced primarily by ecological factors and was indicative of eclectic food habits and the relatively extensive home ranges occupied by these mustelids.

Acanthocephala↗
PubMed1998

Gill parasites of mummichogs, Fundulus heteroclitus (Teleostei: Cyprinodontidae): effects of season, locality, and host sex and size.

I investigated the prevalences and densities of gill parasites in 4 seasonal samples of mummichog, Fundulus heteroclitus (n=242), from 2 creeks differing in salinity in central Chesapeake Bay. The parasites (and overall prevalence ranges) were: mobile (12-88%) and sessile (0-50%) peritrichs (Ciliophora); Myxobolus funduli (58-94%) (Myxozoa); Gyrodactylidae (0-94%) (includes Gyrodactylus sp. and Fundulotrema sp.) and Salsuginus sp. (74-100%) (Monogenea); metacercariae of Phagicola diminuta (75-100%) and Echinochasmus schwartzi (79-100%) (Digenea); Ergasilus manicatus (25-100%) (Copepoda); Lironeca ovalis (0-11%) (Isopoda); and cysts of unknown etiology, or CUEs (64-94%) (unknown taxon). CUEs were more abundant in fall and gyrodactylids in winter. The myxozoan, copepod, and 1 species of digenean were most abundant in spring. Except for gyrodactylids and CUEs, densities were greater in the less saline creek for all taxa. There were no significant differences between sexes except in 1 sample; digenean densities increased with host length for females but not males. There was a strong positive relationship of CUE density with host length and weaker positive associations of gyrodactylid and Salsuginus sp. densities with host length.

Animals↗
PubMed1995

The ecology of endoparasitic helminth infections of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) in Scotland.

Two hundred and forty brown trout (Salmo trutta) and 49 rainbow trout (Oncorhynchus mykiss), obtained from 21 locations in Central Scotland between October 1990 and August 1993, were examined for endoparasitic helminth infections. Crepidostomum farionis (Digenea) was the most widely distributed helminth species, followed by Eubothrium crassum (Cestoda), Diphyllobothrium dendriticum and D. ditremum (Cestoda), Neoechinorhynchus rutili (Acanthocephala), Echinorhynchus truttae (Acanthocephala), Eustrongylides sp. (Nematoda), Capillaria salvelini (Nematoda), Cyathocephalus truncatus (Cestoda), Raphidascaris acus (Nematoda) and Cystidicola farionis (Nematoda), in that order. The prevalences and intensities of each helminth infection were recorded. No evidence was found to indicate that even fish with the highest worm burdens (e.g. 339 plerocercoids of Diphyllobothrium spp.) were experiencing any obvious morbidity. An analysis of pairs of associations between species of helminths revealed a significantly positive association between N. rutili and C. farionis (P < 0.01). The results are discussed in terms of patterns in helminth communities in freshwater fish.

Acanthocephala↗
PubMed2006

Spatial covariation between infection levels and intermediate host densities in two trematode species.

Both theoretical arguments and empirical evidence suggest that parasite transmission depends on host density. In helminths with complex life cycles, however, it is not clear which host, if any, is the most important. Here, the relationships between the abundance of metacercariae in second intermediate hosts, and the local density of both the first and second intermediate hosts of two trematode species, are investigated. Samples of the snail Potamopyrgus antipodarum, the amphipod Paracalliope fluviatilis and the isopod Austridotea annectens were collected from ten stations in a New Zealand lake. In the trematode Coitocaecum parvum, neither the density of the snail first intermediate host nor that of the amphipod second intermediate host correlated with infection levels in amphipods. In contrast, in the trematode Microphallus, infection levels in isopod second intermediate hosts were positively associated with isopod density and negatively associated with the density of snail first intermediate hosts. These relationships are explained by a negative correlation between snail and isopod densities, mediated in part by their different use of macrophyte beds in the lake. Overall, the results suggest that, at least for Microphallus, local infection levels depend on local intermediate host densities.

Amphipoda↗
PubMed1999

Epidemiology of parasitoses in dairy animals in the North West Humid Himalayan Region of India with particular reference to gastrointestinal nematodes.

A systematic survey was conducted during two spells of 5 years each (1986-1990 and 1993-1997) to study the prevalence of parasitoses with particular reference to gastrointestinal (GI) nematodes and flukes in dairy animals (crossbred and native cattle, and buffaloes) belonging to 12 villages in the Kangra valley (Himachal Pradesh). Flukes (Fasciola, amphistomes and Dicrocoelium) and strongyles were the most important parasitic infections. Fasciola was endemic throughout the year, with a higher percentage infection in buffaloes than in cattle. Other fluke and nematode infections showed a seasonal pattern in prevalence, with a small peak in March April followed by a high peak in July September. The faecal egg counts (eggs per gram, epg) of flukes (Fasciola/amphistomes) ranged from 50 to 300 in cattle and 50 to 400 in buffaloes, with high loads during the rainy and post-rainy seasons. The GI nematode egg counts (excluding Toxocara) revealed a similar trend, with the overall monthly mean epg ranging from 85 to 1720 in cattle and 90 to 1625 in buffaloes, with a high peak during the months of July to September. On coproculture of positive samples, the nematode infections in order of prevalence were: Strongyloides, Trichostrongylus, Haemonchus, Oesophagostomum, Bunostomum and Mecistocirrus. The prevalence of most of the parasites was lower during the second 5-year period.

Ancylostomatoidea↗
PubMed1975

Mekong schistosomiasis. III: a parasitological survey of domestic water buffalo (Bubalus bubalis) on Khong Island, Laos.

Of 103 water buffalo (Bubalus bubalis) examined on Khong Island by means of the M.I.F.C. and hatching techniques, none were passing eggs resimbling those of the Mekong schistosome. One buffalo calf was infected with Orientobilharzia harinasutai and another with Schistosoma spindale; this is the first time these parasites have been reported from Laos. Since the buffalo that were examined had constant and year-round access to a part of the Mekong River that has been shown to be a site of heavy transmission of schistosomiasis to humans and dogs, it was considered that the buffalo would have acquired the infection with the human Mekong schistosome if this were possible. In the absence of buffalo necropsies, and since no eggs of the Mekong schistosome were detected in the stools of these animals, we assumed that they had either not become infected with this parasite or, if they had, that the infections did not produce eggs in the faeces which were detectable by the methods employed. On the basis of our examinations, it would not seem that domestic water buffalo are involved as reservoirs in the epidemiology of human schistosomiasis on Khong Island.

Animals↗
PubMed2000

Development and intensity dependence of Ornithodiplostomum ptychocheilus metacercariae in fathead minnows (Pimephales promelas).

Intensity-dependent development of Ornithodiplostomum ptychocheilus metacercariae was studied in fathead minnows (Pimephales promelas) exposed to 0, 20, or 120 cercariae. Subsamples of hosts were necropsied at 2-wk intervals to monitor parasite recruitment, growth, and time to encystment. The complex development of metacercariae within the cranium of minnows involved growth, encystment, and consolidation phases, each of which were affected by intensity. At the end of the growth phase, metacercariae from low-dose fish were 20% longer than those from high-dose fish and the latter took 2-4 wk longer to encyst. At the end of the postencystment consolidation phase (6-8 wk postinfection), the size of metacercariae decreased by approximately 50%. The rate of consolidation was slower in high-dose fish. Our results show that time, intensity, and temperature affect development of O. ptychocheilus. Because metacercariae development and differentiation are linked to infectivity, events occurring in intermediate hosts can potentially impact the structure and size of trematode suprapopulations.

Animals↗
PubMed1982

[Study of the therapeutic efficacy of Nilsan preparation against Paramphistomatidae and nematode infections in sheep].

Experiments were carried out with the preparation Nilsan (oxiclozanide + levamizal) in the treatment of sheep with Fasciola, Dictyocaulus, and Trichostrongylus infection. The trials involved a total of 2782 sheep on two sheep-breeding farms, constituting 15 flocks. The liveweight of the adult animals ranged from 40 to 60 kg, and that of the year-old female ones--from 40 to 45 kg. The daily ration on the two farms did not differ essentially from that offered to the animals in the past 2-3 years. It was found that at the rate of 22 to 28 cm3 per head Nilsan produced 76.67 to 96.67 percent effect against Paramphistomum infection, 100 percent effect against Dictyocaulus infection, 73.37 to 90.00 percent effect against Trichostrongylus infection, and 23.34 to 83.34 percent effect against Dicrocelium infection. The application of an ex tempore combination of oxiclozanide and levamizal to sheep at the rate of 24 cm3 per head produced 86.67 to 100 percent effect against Paramphistomum, 96.67 to 100 percent effect against Dictyocaulus, 86.67 to 96.67 percent effect against Trichostrongylus, and 46.67 to 86.67 percent effect against Dicrocelium. The experimental sheep produced 16.41 to 37.40 per cent more wool, 0.85 to 35.09 per cent more milk, and 8 to 12 per cent more weight gain.

Animals↗