On the statistical analysis of worm counts in chickens.
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Animals↗
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Results for “NEMATODE INFECTIONS”
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Dirofilaria immitis: identification and characterization of circulating parasite antigens.
A method for the identification of circulating parasite antigens in filarial nematode infections was developed using canine infections with Dirofilaria immitis as a model. Filarial antigens ranging in molecular weight from 211 to 13 kDa were extracted from the sera of microfilaremic dogs by a solid phase immunobinding procedure and identified by immunostaining of Western blots. A major antigen of 104 kDa was selected for further characterization. The 104 kDa circulating antigen showed antigenic and biochemical identity with 104 kDa peptides found in extracts of adult male and microfilarial stages of the parasite. The 104 kDa peptide was antigenically stable under a variety of storage conditions. Its potential as a diagnostic target is discussed.
Animals↗
Surface antigens of male worms and microfilariae of Onchocerca gibsoni.
Living adult males and microfilariae of the cattle filarial parasite Onchocerca gibsoni were externally labelled with radioactive iodine using the iodogen and Bolton-Hunter procedures. Characterization of labelled surface proteins by sodium dodecyl sulphate (SDS)-polyacrylamide gel electrophoresis revealed clear cut differences in the two life cycle stages. In addition, the two radiolabelling procedures yielded some differences in the profiles of radiolabelled surface proteins for both adults and microfilariae. Immunoprecipitation analysis revealed a number of labelled antigens recognized by antibodies in human onchocerciasis serum pools, thereby demonstrating the usefulness of O. gibsoni as a model in Onchocerca volvulus vaccine studies. The reactivity of microfilarial antigens extended to antibodies from other human nematode infections, whereas male surface antigens, particularly those of low molecular weight, were Onchocerca specific. This indicates that O. gibsoni can provide a convenient source of specific diagnostic antigen.
Animals↗
A case of ileus caused by a spiruroid nematode.
A 34-year-old male living in Aichi Prefecture, Japan, complained of lower abdominal pain. Ileus was suspected based on his clinical history and symptoms, and a laparotomy was performed. Four sections of a nematode were found in a large eosinophilic granuloma in the intestinal wall, and were identified as the larva of a spiruroid nematode. This is the third reported case of a spiruroid nematode infection found in the ileum.
Adult↗
Intrapulmonary lymphoid tissue of pigs exposed to aerosols of carbon particles, of Salmonella oranienburg, of Mycoplasma granularum, and to an oral inoculum of larvae of Metastrongylus apri.
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Aerosols↗
Disseminated granulomatous disease in a cat caused by larvae of Toxocara canis.
The gross and histological findings of a case of disseminated granulomatous disease caused by larval nematode infection in a cat are presented. The larvae were identified as those of Toxocara canis and the lesions associated with infection of cats with various ascaridoid larvae are discussed.
Animals↗
Larva migrans that affect the mouth.
As air travel expands, tropical diseases are increasingly likely to be encountered. We report a case of a nematode infection from dogs and cats that appeared in the mouth as larva migrans, and we review the literature.
Adult↗
The contribution of infections to protein-calorie deficiency.
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Animals↗
Characterization, cloning and host-protective activity of a 30-kilodalton glycoprotein secreted by the parasitic stages of Trichostrongylus colubriformis.
The helminth Trichostrongylus colubriformis is a parasitic nematode infecting the small intestine of sheep. We report the isolation and characterization of a 30-kDa glycoprotein capable of partially protecting guinea-pigs against the parasite. This glycoprotein is secreted by the L4 and adult parasitic stages of the worm. The sequence of three separate cDNA clones predicts the polypeptide to be about 15 kDa, with four N-linked carbohydrate chains and an internal disulphide bond. The clones also indicate the existence of sequence variability in this antigen. Limited sequence homology to a porcine intestinal peptide suggests an influence on host gut physiology.
Amino Acid Sequence↗
Vaccines against gastrointestinal nematode parasites of ruminants.
A consequence of intensive livestock production is an increase in the incidence and impact of gastrointestinal (GI) parasites. Farmers have sought to redress this shift in the natural host-parasite relationship by chemotherapy. However, with the widespread development of resistance to anthelmintics and the current impetus for sustainable agricultural practices, alternatives such as vaccines are being sought to maintain animal productivity. In this article, David Emery and Barry Wagland discuss recent advances in immunity to nematode infections of ruminants and the development of vaccines made possible by the dogged persistence and ingenuity of cadres of parasitologists who have done more than 'go through the motions'.
Journal Article↗
Photodynamic action of erythrosin B as a toxic mechanism for infective larvae of bovine gastrointestinal nematodes.
The effect of erythrosin B on adults and 3rd stage larvae of gastrointestinal nematodes of cattle was studied by treating calves per os with 20 mg kg-1, 40 mg kg-1, and 60 mg kg-1 of the dye daily for 21 days and monitoring its effect. Erythrosin B had no detectable effect on adult nematode fecundity or viability. Data collected did indicate, however, that erythrosin B produced a consistent toxic effect on 3rd stage larvae after exposure to fluorescent light. This toxic effect was dependent upon dosage of erythrosin B administered, time of light exposure and, to a much lesser extent, the length of time the larvae were left in culture in the presence of the dye.
Animals↗
The relation between the natural worm burden of steers and the faecal egg count differentiated to species.
The relation between the faecal egg count and the worm burden was investigated in 104 steers of three breeds, 9-24 months of age, which were subjected to natural infection with nematode larvae from pasture at The National Cattle Breeding Station near Rockhampton in central Queensland. The worm species found were Cooperia spp., Haemonchus placei, Trichostrongylus axei, Oesophagostomum radiatum and small numbers of Bunostumum phlebotumum. The faecal egg count was found to be a reliable measure of the size of the worm burden. Steers slaughtered at 24 months of age had 90% fewer worms and 96% fewer eggs g-1 faeces (P less than 0.001) than those slaughtered at 9 months of age. Adjusted for age, the estimated faecal egg count increased 14 times (95% confidence limits 7.2, 35) for each 10-fold increase in estimated worm numbers. The proportion of each species of larvae obtained from faecal culture (larval differential count) was related to the composition of the worm burden as measured by the proportion of worms in selected maturity categories and in selected length categories for each species (P less than 0.001).
Analysis of Variance↗
Development of resistance to Trichostrongylus colubriformis in goats.
A high level of host resistance to Trichostrongylus colubriformis was established in a group of Saanen goats infected weekly with 10,000 infective larvae for 10 weeks, treated with an anthelmintic and then challenged twice with 50,000 larvae, with a further anthelmintic treatment 28 days after the first challenge. A second group of goats exposed only to the two challenge infections developed worm burdens intermediate between, and significantly different from, the first group and a third control group given only the second challenge infection. Nematode fecundity (eggs per female) and male:female ratios were also significantly decreased in the first two groups. Faecal egg counts and worm counts were highly correlated and this relationship was dominated by the influence of the number of eggs/female nematode. The goats were approximately 9 months old at the start of the experiment.
Analysis of Variance↗
Enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to Anoplocephala perfoliata in horse sera.
A scolex antigen of the horse tapeworm Anoplocephala perfoliata containing at least 14 different proteins was employed in an enzyme-linked immunosorbent assay (ELISA) for detection of antibodies to A. perfoliata in equine sera. The assay was applied to sera from 426 slaughtered horses with different numbers of worms and with varying degrees of intestinal lesions. As measured by the ELISA, there was a very strong effect on the antibody levels both from the number of tapeworms present and from the intestinal lesion score. However, considerable individual variation was observed between horses with similar worm counts. The ELISA values of horses that were either negative for strongyles and tapeworms or positive only for strongyles were similar, whereas both of these groups differed significantly from animals that harboured only A. perfoliata. Thus it seemed that cross-reactivity with concurrent nematode infections did not occur. Furthermore, a significant seasonal pattern in antibody levels was observed which reflected the establishment of newly acquired infections. No observations were made of confounding effects owing to age and previous anthelmintic treatment of the horses. It is concluded that the ELISA presented here has a potential for monitoring A. perfoliata infection on a herd level and can be used as a complementary diagnostic tool in epidemiological studies. The present study indicates that transmission of A. perfoliata in Central Sweden occurred during a short period in spring and more consistently in late autumn.
Aging↗
Ivermectin resistant Haemonchus contortus in Louisiana lambs.
Fifteen weaned crossbred (Suffolk x Louisiana Native) lambs were treated with albendazole (10 mg kg-1) to remove existing nematode infections. They were inoculated with Haemonchus contortus infective larvae from a residual population surviving treatment with the oral formulation of ivermectin (0.2 mg kg-1). One group of five lambs remained untreated, another group of five was treated with the injectable formulation of ivermectin (0.2 mg kg-1), and a third group of five was treated with the oral formulation of ivermectin (0.2 mg kg-1). Subsequent to the treatments, there was essentially no difference in mean fecal egg count or mean number of H. contortus recovered at necropsy between the three groups.
Albendazole↗
Prevalence and epidemiology of trichostrongylids in Wyoming cattle with consideration of the inhibited development of Ostertagia ostertagi.
During 1988, monthly collections of abomasa and the cranial portion of the small intestine of 208 native Wyoming cattle were examined for adult and larval helminth parasites. Egg counts were performed on colonic faecal specimens. The animals ranged from 7 months to 8 years of age and were sampled at slaughter houses or diagnostic laboratories from five different counties in the State. Most of the cattle had ranged for a long time on non-irrigated, high altitude grass plains from about 1250 to 2500 m above sea level. All animals examined were found infected. Nematode genera (and number of species) found included Ostertagia (4), Trichostrongylus (2), Haemonchus (1), Cooperia (4) and Nematodirus (2). One trematode, Fasciola hepatica, and a cestode, Moniezia benedeni, also were found. Trichostrongylus axei, Trichostrongylus longispicularis and Cooperia lyrata were found for the first time in Wyoming, Ostertagia circumcincta was found for the first time in cattle in Wyoming, and Haemonchus placei, tentatively identified in a previous survey, was definitively confirmed. Predominant species (and prevalence) were Ostertagia ostertagi (98%), Cooperia oncophora (60.6%), Ostertagia bisonis (41.8%), Cooperia bisonis (33.6%) and T. Axei (27.9%). One or more of the four species of Ostertagia were found in all animals. Inhibited O. ostertagi and O. bisonis larvae predominated from November to April and reached a peak in January to comprise 88% of the total nematode burden for that month. The adult population of abomasal nematodes peaked in April and predominated thereafter until October. Haemonchus placei also spent the autumn-winter period in an inhibited state of development. Faecal egg counts were lowest during winter months, when the highest number of worms were present as L4 larvae, as determined by luminal and mucosal counts. Nematode populations in the small intestine peaked in June and persisted until November. The results of this study showed the magnitude and species composition of nematode parasitism in cattle raised on high altitude grass plains, underscored the inaccuracy of faecal egg counts as an indicator of worm burden during fall and winter seasons, and provided information on which anthelmintic treatment timing would be most efficacious.
Abomasum↗
Molecular characterisation and developmental expression of a cellulose-binding protein gene in the soybean cyst nematode Heterodera glycines.
Secretory proteins encoded by 'parasitism genes' expressed in the oesophageal gland cells of plant-parasitic nematodes play key roles in nematode infection and parasitism of host plants. A cellulose-binding protein-encoding cDNA, designated Hg-cbp-1, was cloned from a Heterodera glycines oesophageal gland-cell long-distance PCR cDNA library. The cDNA hybridised to genomic DNA of H. glycines in Southern blots, and the genomic sequence of Hg-cbp-1 contained only one intron. The Hg-cbp-1 cDNA contained an open reading frame encoding 132 amino acids, with a predicted signal peptide sequence for secretion and a cellulose-binding domain. Bacterial expressed recombinant HG-CBP-1, minus the signal peptide sequence, had no hydrolytic activity on carboxymethyl-cellulose but was able to bind to cellulose. The developmental expression of Hg-cbp-1, determined by real-time reverse transcriptase PCR, showed that Hg-cbp-1 is expressed throughout the parasitic cycle of H. glycines, with a relatively higher expression level in developing parasitic stages.
Amino Acid Sequence↗
Mermithid parasitism of Hawaiian Tetragnatha spiders in a fragmented landscape.
Hawaiian Tetragnatha spiders inhabiting small forest fragments on the Big Island of Hawaii are parasitized by mermithid nematodes. This is the first report of mermithid nematodes infecting spiders in Hawaii, and an initial attempt to characterize this host-parasite interaction. Because immature mermithids were not morphologically identifiable, a molecular identification was performed. A phylogenetic analysis based on 18S small ribosomal subunit nuclear gene sequences suggested that Hawaiian spider mermithids are more closely related to a mainland presumptive Aranimemis species that infects spiders, than to an insect-infecting mermithid collected on Oahu, HI, or to Mermis nigrescens, also a parasite of insects. Measured infection prevalence was low (ranging from 0 to 4%) but differed significantly among forest fragments. Infection prevalence was associated significantly with fragment area, but not with spider density nor spider species richness. Results suggest that mermithid populations are sensitive to habitat fragmentation, but that changes in infection prevalence do not appear to affect spider community structure.
Animals↗