The identification of risk and essential elements along the strobila of the rat tapeworm Hymenolepis diminuta.

The rat tapeworm Hymenolepis diminuta can bioconcentrate several elements to conspicuously higher concentrations than tissues of their definitive host. The main aim of this study was to locate parts of the tapeworm into which lead, cadmium, zinc, copper, manganese and iron are accumulated. Male Wistar rats were experimentally infected with H. diminuta and worms were exposed to two different forms of lead for 6 weeks through the oral exposure of their rat hosts. After the exposure period, the element levels were determined in the posterior and anterior proglottids of the tapeworm. In all cases, lead concentrations were higher in the anterior parts than the posterior parts. Concentrations of cadmium, copper, iron, manganese and zinc were also significantly higher in the anterior parts. Zinc concentrations showed an opposite trend, with higher zinc levels detected in the posterior part of the strobila, in the control group. The present study demonstrates that risk and essential elements are accumulated mainly into the anterior part of H. diminuta.

The effect of Syphacia muris on nutrient digestibility in laboratory rats.

This study was carried out to investigate how pinworm infection in rats affects nutrient digestibility in the hosts. Twenty-four male outbred Wistar rats were randomly divided into two groups of 12 rats each. The rats from the first group (GI) were kept in cages with bedding containing pinworm eggs, and the second (control) group (GII) were kept in a separate room in clean, uncontaminated filter-top cages. The animals were put into individual metabolic cages later. Metabolic trials lasted five days and records of animal weight, food ingestion, and faecal weight were taken daily. Based on laboratory analysis of the feed and faecal nutrient content, digestibility values were determined. On day 15 of the experiment, the animals were euthanized. Although Syphacia muris were found in all rats from the GI group, animals exhibited no clinical signs. In our experiment, S. muris infection reduced the overall digestibility of all measured nutrients (P < 0.01). The most significant differences in digestibility were observed in the case of crude fibre and mineral matter (P < 0.01).

Effects of age, sex, lactation and social dominance on faecal egg count patterns of gastrointestinal nematodes in farmed eland (Taurotragus oryx).

The eland is a large African antelope that can be bred in a temperate climate, under similar conditions and production systems as cattle. However, knowledge of parasites in farmed elands outside the area of their native habitat is still limited, and information concerning factors that influence these parasites is lacking. Therefore, faecal samples from an entire herd of elands, including calves and adult females and males, were examined monthly over a one year period. Almost 84% of the animals were found to be positive for gastrointestinal nematodes. Strongyle-type eggs were most frequently detected (prevalence 75%), followed by Capillaria sp., Nematodirus sp. and Trichuris sp. eggs. Following culturing eggs to infective larvae, Teladorsagia sp., Trichostrongylus sp., Nematodirus sp., Cooperia sp. and Oesophagostomum sp. were identified. Following necropsy of two calves that died during the study one abomasal nematode (Teladorsagia circumcincta), five small intestinal nematode species (Nematodirus helvetianus, N. spathiger, Cooperia oncophora, C. curticei and Capillaria bovis) and two large intestinal nematodes (Oesophagostomum venulosum and Trichuris ovis) were recovered. From these findings, it is evident that the eland harbours nematodes that are typical for domestic cattle and small ruminants. Morphological and morphometric analyses of recovered nematodes revealed that these parasites do not require any special morphological adaptation to establish infection in elands. The faecal output of strongyle-type and Nematodirus sp. eggs was seasonal, with the highest egg production taking place during spring and summer. Calves had higher faecal egg counts (for all the monitored nematode species) than adults did. Lactation in females was significantly (P<0.0001) associated with higher strongyle nematode egg shedding. Social dominance also affected faecal egg count patterns. The lower the hierarchical position among adults (regardless of sex), the higher the risk of nematode infection. This effect was evident for strongyles (P<0.0001) and Capillaria sp. nematodes (P=0.0065). The results of our study suggest that control measures applicable in domestic cattle and small ruminants might be similarly applicable for controlling gastrointestinal nematode infections in captive farmed elands.

Genetic and morphological characterization of Trichuris myocastoris found in Myocastor coypus in the Czech Republic.

Trichuris sp. individuals were collected from Myocastor coypus from fancy breeder farms in the Czech Republic. Using morphological and biometrical methods, 30 female and 30 male nematodes were identified as Trichuris myocastoris. This paper presents the first molecular description of this species. The ribosomal DNA (rDNA) region, consisting of internal transcribed spacer (ITS)-1, 5.8 gene and ITS-2, was sequenced. Based on an analysis of 651 bp, T. myocastoris was found to be different from any other Trichuris species for which published sequencing of the ITS region is available. The phylogenetic relationships were estimated using the maximum parsimony methods and Bayesian analyses. T. myocastoris was found to be significantly closely related to Trichuris of rodents than those of ruminants.

Effect of Acanthocephalus lucii infection on total mercury concentrations in muscle and gonads of fish host (Perca fluviatilis).

The samples from 13 perches (Perca fluviatilis) - muscle with skin and bones; fish gonads; and acanthocephalan parasites were analysed for mercury (Hg). Hg concentrations were present in all analysed samples. There were found no statistically significant difference in Hg concentration in fish tissues between perches either with or without infection by the acanthocephalan parasite, Acanthocephalus lucii). In this study there was no evidence that acanthocephalan worms accumulate mercury from hosts. For this reason, A. lucii is not a suitable bioindicator for mercury pollution.

Effect of lead in water on the absorption of copper, iron, manganese and zinc by sheep (Ovis aries) infected with sheep tapeworm (Moniezia expansa).

The sheep tapeworm (Moniezia expansa) and its host Ovis aries were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES) for their copper, iron, manganese, zinc and lead levels. Element concentrations in cestode parasites were compared to those in various organs (liver, kidney, and muscle) of sheep. Tapeworms in the small intestine of sheep that were administered 2g of Pb(CH(3)COO)(2) per os daily (7 days) had significantly higher lead concentrations than sheep tissues. Cu levels significantly increased after Pb administration in sheep muscle and sheep tapeworms. Contrarily, Zn content significantly decreased in sheep muscle, but significantly increased in sheep tapeworms. However, Mn content significantly decreased after Pb administration in sheep tapeworms. Furthermore, Fe content significantly decreased after Pb administration in sheep liver and kidneys.

The initial discovery of thorny-headed worms in sheep.

Acanthocephalans belonging to the species Acanthocephalus lucii were found in the colon of a lamb from ecological farms in the Czech Republic. The main determination features used for these acanthocephalans are the shape and size of the hooks as well as the number of hooks on the proboscis. Three immature specimens measured 5.0-13.2mm in length; the appearance of the acanthocephalan body (in the studied material) suggests that passage through this unusual host causes the cystacanths to slightly increase in length. In the case of the lambs examined, the infection may be acquired through the accidental ingestion of the intermediate host - waterlouse (Asellus aquaticus).

Experimental studies on the cadmium accumulation in the cestode Moniezia expansa (Cestoda: Anoplocephalidae) and its final host (Ovis aries).

The tapeworm Moniezia expansa and naturally infected sheep were investigated with respect to their cadmium accumulation. Cadmium chloride (CdCl(2), 0.2 g) was added to 10 ml of distilled water and administered orally to the sheep every day for a period of 1 week. The cadmium content of M. expansa was lower than that in the liver tissues of sheep, although this difference was not significant. The highest mean cadmium concentrations were found in the liver of sheep infected with M. expansa (24.5+/-11.5 mgkg(-1) dry weight). The mean cadmium concentration measured in M. expansa was 21.5+/-19.2 mgkg(-1) dry weight, which was 31 and 1.5 times higher than levels determined in the muscle and kidney of the host, respectively, but 0.9 times lower than levels determined in the liver of host. Sheeps with M. expansa infection always had higher cadmium concentrations in the tissues (with the exception of the blood) than their uninfected conspecifics.