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PubMed1997

An attempt to control lungworm disease and parasitic gastroenteritis on commercial dairy farms by the use of an adaptation of Michel's dose-and-move system.

On seven dairy farms an attempt was made to control lungworm disease in calves by turnout on a pasture grazed earlier by cows, followed by a move to aftermath and ivermectin treatment 2 months later. Transmission of lungworm was observed on all farms. Lungworm disease occurred on four farms at treatment. Coughing re-occurred on three of these farms in some animals 2 months later. Owing to poor performance between turnout and treatment, weight gain was below the norm on the farm with the highest infections and most severe respiratory signs. On the other farms respiratory signs did not result in poor weight gain. Gastrointestinal nematode infections remained low on all farms. The conclusion is that this dose and move scheme cannot be recommended for the control of lungworm.

Animals↗
PubMedDate not supplied

ELISA antibody determination in patients with anisakiosis or toxocariosis using affinity chromatography purified antigen.

One of the fundamental aspects of a parasitic infection diagnosis is the use of adequate antigens to develop specific and sensitive immunoassays. This fact is especially complicated in nematode infection cases because of the high cross-reactivity among different parasites in this group. We performed an evaluation of Anisakis simplex antigens purified by affinity chromatography. We used sera from 38 patients diagnosed with Anisakis sensitization and sera from 35 patients with clinical suspicion of visceral larva migrans (VLM). These sera were assayed by the ELISA method against the crude extracts (CEs) and the purified antigens. When the sera from patients diagnosed with Anisakis sensitization were tested against the A. simplex CE, the IgG was the most abundant immunoglobulin. When the A. simplex larval antigens were purified using a column of IgG anti-A. simplex (PAK) or a column of IgG anti-Ascaris suum (PAS) were tested, we observed a higher diminution in the IgG levels, which coincides with the augmentation of the mean values against the "eluted of Ascaris" (EAS antigen). When the IgE was detected, only 18.4% of the sera reacted with the PAS antigen. We have observed that in the purification process of A. simplex antigen by affinity chromatography, the majority of the proteins that produced cross-reactivity against A. suum and Toxocara canis were eliminated.

Animals↗
PubMed1992

The significance of the "lung phase" in host-helminth relations.

Many helminth infections have a "lung phase" whose significance considering the host-parasite relations has not yet been clarified. In some nematode infections larvae must pass through the lungs, in others adult worms live in the respiratory tract, and some others cause tropical pulmonary eosinophilia. Some examples of these infections (Nippostrongylus brasiliensis, Schistosoma mansoni, Trichinella spiralis and Toxocara canis) are considered to clarify whether this phase of infection is a "pro-host" or a "pro-parasite" mechanism. Whereas in primary infections--in some cases--transit through the lungs may render the parasite more resistant to host defence mechanisms (e.g., Schistosoma and perhaps Trichinella infections) or enables completion of the cycle (Nippostrongylus and Toxocara infections), in secondary infections the lungs might be the site of parasite killing.

Animals↗
PubMed1989

Increased establishment of lungworms (Dictyocaulus viviparus) in calves after previous infections with gastrointestinal nematodes (Ostertagia ostertagi and Cooperia oncophora).

The influence of a priming infection with gastrointestinal nematodes on the subsequent establishment of lungworms was studied. Repeated inoculations of calves with Ostertagia ostertagi and Cooperia oncophora during 3, 5 or 7 weeks resulted in an establishment of lungworms that was 191% of the establishment found in naïve controls. The higher take was associated with a higher faecal output of lungworm larvae and with lower weight gains of calves. The effect was not significantly influenced by the duration of the primary infections or by the actual presence or absence of worms in the gastrointestinal tract.

Analysis of Variance↗
PubMed1992

Morphology of the bile ducts of the brook lamprey, Lampetra lamottenii (Le Sueur) before and during infection with the nematode, Truttaedacnitis stelmioides (Vessichelli, 1910) (Nematoda: Cucullanidae).

Routine light microscopy and transmission and scanning electron microscopy were used to describe and compare the biliary tree of larval Lampetra lamottenii before and during infestation of the bile ducts with the nematode, Truttaedacnitis stelmioides. The most prominent changes to the biliary tree following infection by the parasite are the dilation of the bile ducts, alterations to their epithelial cells, and an increase in periductal fibrous tissue. In recently infected animals, the simple epithelium of dilated bile ducts often contains many mitotic figures. In long-term infestations, the epithelium is stratified or pseudostratified. Changes to the fine structure of the biliary epithelial cells include increase and/or dilation of the RER and SER, and increases in microfilaments, intermediate filaments, and microtubules. The abundance of dense bodies may reflect enhance reabsorption of biliary constituents, and their accumulation may ultimately result in cytolysis. There are increased mucous granules in the apical cytoplasm of biliary epithelial cells and an abundance of mucinous material within the bile duct lumen, and the basal lamina appears thickened. The changes to the liver of L. lamottenii following infection are discussed and compared to those reported in small mammals following bile duct ligation, in patients with extrahepatic biliary obstruction, and in parasitic infection of the biliary tree.

Animals↗
PubMed2001

A field survey on the status of internal parasites in calves on organic dairy farms in southwestern Sweden.

Infections with internal parasites are one of the most important causes of reduced productivity in first-grazing season cattle (FGSC). In conventional herds, nematode infections can be controlled by prophylactic anthelmintic treatments, but this is prohibited in organic production. The purpose of this investigation was to monitor the status of internal parasitism on 15 organic cattle enterprises in southwestern Sweden during the 1997 and 1998 grazing seasons, and to estimate the benefits of some management practices in parasite control. On each farm, the numbers of Eimeria alabamensis oocysts per gram of (opg) faeces were counted in seven fresh dung pats collected from the paddock 8-10 days after the turnout of FGSC. Faecal samples from 5 to 15 FGSC were also analysed for nematode eggs per gram (epg) faeces at four occasions during each grazing season. In addition, the FGSC and one group of second-grazing season cattle (SGSC) were weighed at turnout and housing and at the same time blood samples were collected, and analysed for serum pepsinogen concentration and antibodies against the lungworm, Dictyocaulus viviparus. On seven farms, 1-6 samples with more than 100000 opg were found, indicating considerable pasture contamination by E. alabamensis. However, clinical signs of coccidiosis were not observed. The highest outputs of nematode eggs were observed 45-55 days after turnout. More than 500 epg were only observed in 12 (2.2%) of the calves in 1997 and in three (0.6%) animals in 1998. Only 1% of the serum samples had pepsinogen values exceeding 3.6 U tyrosine, indicative of subclinical Ostertagia ostertagi infection. Lungworm infection was detected in five and nine herds in 1997 and 1998, respectively. The number of seropositive animals on these farms ranged between one (10%) and seven (70%). Clinical signs of dictyocaulosis were observed on two farms. The results indicate that dictyocaulosis is a problem in organic dairy herds in Sweden. On the other hand, the study shows that good management such as usage of parasite safe pastures and supplementary feeding may help control gastrointestinal parasites.

Animals↗
PubMed1996

Comparison between fenbendazole and moxidectin applied in a dose and move system for the control of Dictyocaulus viviparus infections in calves.

A grazing study was performed with the main objective to compare the effect of moxidectin (MDT) and fenbendazole (FBZ) in a 'dose and move' system on nematode infections in calves with special emphasis on Dictyocaulus viviparus. Three groups of six calves were grazed from May to October 1994. All groups grazed together until 9 weeks after turnout when they were moved to separate mowed pastures. One group (MM) was then treated with 0.5 mg kg-1 MDT pour-on, the second group (FM) was treated with 7.5 mg kg-1 FBZ drench and the third group served as untreated pasture control group (PC). Two calves from MM and two from FM were experimentally infected with 20 lungworm larvae at turnout in order to initiate low infections in the herd. Pairs of tracer calves grazing during the first 7, 8 or 9 weeks after turnout acquired mean burdens of 218, 255 and 1156 lungworms, respectively. MDT and FBZ treatment removed adult lungworms from MM and FM. In PC faecal larval counts increased until the end of July, when most animals were suffering from lungworm disease. No lungworm disease occurred in both dose and move groups. In FM larvae reappeared in the faeces of some of the calves from 1 month after treatment and low patent infections remained to be present in FM in some calves until the end of the experiment. No reappearance of larvae after treatment was observed in MM. The mean Optical Density (OD) values of the three groups on pasture closely followed the infection patterns. After housing in October all calves, and also a group of five permanently housed non-infected control calves (HC), were infected experimentally with 5000 D. viviparus larvae to evaluate development of immunity. The worm counts at necropsy showed that groups on pasture had developed immunity. However, the degree of immunity was lower in MM than in FM and PC.

Animal Husbandry↗
PubMed2000

Comparative study of strongyle infections of cattle and buffaloes in Mindanao, the Philippines.

Faecal samples were collected from 500 cattle and 385 buffaloes belonging to backyard farmers from 24 villages in the province of Bukidnon, Mindanao, the Philippines. Strongyle nematode infections were studied on these samples by faecal egg counts and infective larvae differentiation. The effects of animal species and age on the prevalence and intensity of infections were studied. The overall prevalence of strongyle infection was 53% for cattle and 28% for buffaloes. The prevalence decreased with increasing age in both animal species. Faecal egg counts were significantly lower in buffaloes than in cattle. Adult animals had lower egg counts than calves. This age effect was most pronounced in buffaloes. Six genera of strongyle nematodes were identified from the faecal cultures in both animal species, Mecistocirrus, Haemonchus, Trichostrongylus, Cooperia, Bunostomum and Oesophagostomum. The distribution of larvae did not vary much with age.

Animals↗
PubMed1990

Appetite, digestive efficiency, feed utilization and carcass evaluation of housed calves naturally infected with gastrointestinal nematodes.

The progress of two groups of 10 calves, which had previously been exposed to trichostrongyle infections by grazing infected pastures, was monitored from housing in October to slaughter the following April. Each of the animals of one group had received a morantel sustained release bolus, the other control group remained untreated. The high faecal egg counts and serum pepsinogen concentrations, together with the clinical signs of ostertagiosis observed in the controls in October, persisted during the first month of housing but improved thereafter. From late November onwards, no difference in feed intake and digestive efficiency was observed between the groups. The control calves exhibited a significantly greater feed conversion efficiency over the period February-April, (7.5 vs. 12.3 kg feed kg-1 liveweight gain, P less than 0.001). This reduced the liveweight advantage of the MSRB group over the controls at housing to 25 kg.

Animal Feed↗
PubMed2004

Evaluation of copper supplementation to control Haemonchus contortus infections of sheep in Sweden.

A pen study was conducted to assess the effect of providing daily copper mineral supplement, or copper wire particle (COWP) capsules, on established or incoming mixed nematode infections in young sheep. For lambs with established (6 week old) infections, COWP resulted in 97% and 56% reduction of the adult and early L4 stages of H. contortus, respectively, compared with controls (p<0.001). Additionally there was a 74% reduction in Teladorsagia circumcincta infections in the COWP lambs compared with controls (p<0.01). However, no effect was observed when COWP were given at the commencement of a larval dosing period of 6 weeks. There was no significant effect of copper mineral supplement (given at the recommended rate to prevent Cu deficiency) on either established, or developing parasite infections. In addition, a field trial was conducted on a commercial farm to assess the effects of COWP in the management of recurrent H. contortus infections, but lack of parasites during the grazing season prevented an adequate assessment from being made. These results indicate that there is little, if any, benefit from a parasite control standpoint in recommending copper therapy, specifically to control parasites in Swedish sheep flocks.

Animals↗
PubMed2004

Granulomatous inflammation during Heligmosomoides polygyrus primary infections in FVB mice.

Host responses to primary infections with Heligmosomoides polygyrus were studied in fast responding FVB mice (H-2(q)). Pathological changes in the intestinal mucosa, mesenteric lymph nodes and spleen were examined. Features of the fast response were typical: low effectiveness of infection and limiting of parasite survival and egg production, with worm expulsion occurring about 60 days post-infection. The intestinal inflammatory response involved infiltration by different cells into the intestinal mucosa and granulomata formation. As is typical for intestinal nematode infection enteropathy, decreased villus:crypt ratio and hyperplasia of goblet and Paneth cells were also present. Reactions of the intestinal mucosa, mesenteric lymph nodes and spleen increased over time post-infection and after worm expulsion. Enteropathy may help worm expulsion by creating an unfavourable environment for H. polygyrus. The implications of these findings and the potential role of intestinal intraepithelial lymphocytes in the pathogenesis of generated lesions are discussed.

Animals↗
PubMed2004

Binding of hematin by a new class of glutathione transferase from the blood-feeding parasitic nematode Haemonchus contortus.

The phase II detoxification system glutathione transferase (GST) is associated with the establishment of parasitic nematode infections within the gastrointestinal environment of the mammalian host. We report the functional analysis of a GST from an important worldwide parasitic nematode of small ruminants, Haemonchus contortus. This GST shows limited activity with a range of classical GST substrates but effectively binds hematin. The high-affinity binding site for hematin was not present in the GST showing the most identity, CE07055 from the free-living nematode Caenorhabditis elegans. This finding suggests that the high-affinity binding of hematin may represent a parasite adaptation to blood or tissue feeding from the host.

Animals↗
PubMed1989

Occurrence and metabolic significance of microbodies in trophic hyphae of the nematophagous fungus Arthrobotrys oligospora.

This paper describes the results of an ultrastructural study on the subcellular events occurring in nematode-infecting (trophic) hyphae of the nematophagous fungus Arthrobotrys oligospora. In early stages of the infection process (30 min-4 h), the infection bulb and developing trophic hyphae are characterized by a highly proliferated endoplasmic reticulum (ER). Its membranes often appeared vesiculated and occur in close association with the cell membrane of the cells. Upon further invasion of the nematode, lipid droplets developed in the trophic hyphae; these droplets were first observed 4-5 h after the infection but were abundantly present after 24-36 h. Along with the formation of lipid droplets proliferation of microbodies was observed. These organeles were characterized by the presence of catalase and thiolase and were frequently observed in close association with the lipid droplets. Later on the lipid droplets disappeared. During this period new vegetative mycelium developed from the trap that had originally captured the nematode. Our results suggest that part of the nutrients released from the nematode are first converted into lipids by the fungus which in turn are degraded via the beta-oxidation pathway and further metabolized to support growth of new vegetative hyphae.

Animals↗
PubMed1995

An ivermectin tablet for sheep: efficacy against gastro-intestinal nematodes and a bioavailability comparison with a liquid ivermectin formulation.

An ivermectin tablet for oral administration to sheep was developed for use in countries where it is customary to treat sheep with anthelmintic tablets. Tablets require no special administration equipment, and offer convenience for storage and transport. The ivermectin tablet, which delivers 10 mg of ivermectin (200 micrograms kg-1 in a 50 kg sheep), had similar bioavailability to a liquid formulation of ivermectin (IVOMEC Liquid for Sheep) as determined by peak plasma ivermectin concentrations and area under the concentration curve in plasma (P > 0.10). In dose confirmation trials in which nematode infections were induced in helminth-naive sheep, animals treated with the ivermectin tablet had significantly fewer adult and fourth-stage larval nematodes than untreated control sheep (P < 0.01) with efficacies > 99% against all nematode species tested. In six field trials evaluating the efficacy of the ivermectin tablet in 240 Merino sheep, the reductions in faecal nematode egg counts ranged between 98 and 100%, as determined by comparison of pre- and post-treatment counts for the ivermectin-treated group.

Administration, Oral↗
PubMed2003

Macrophages in chronic type 2 inflammation have a novel phenotype characterized by the abundant expression of Ym1 and Fizz1 that can be partly replicated in vitro.

Using a murine model of nematode infection, we have discovered macrophages that display a novel phenotype that may be characteristic of macrophages in chronic type 2 inflammation. These nematode-elicited macrophages (NeMphi) are characterized by two unique features: the ability to actively suppress proliferation of a broad range of cell types and the high level expression of two novel macrophage genes, Ym1 and Fizz1. NeMphi also show some similarities with in vitro-derived 'alternatively activated macrophages' such as the downregulation of inflammatory cytokines. We therefore investigated how much of the phenotype discovered in vivo could be replicated by activation with Th2 cytokines in vitro. Fizz1 and Ym1 were upregulated by IL-4 and IL-13 in vitro but at a considerably lower level than in NeMphi. In vitro treatment with IL-4 could also partly replicate the ability of NeMphi to block cellular proliferation. As well as the quantitative differences in gene expression and suppressive phenotype, we also observed phenotypic differences in the cell morphology between macrophages activated in vivo and in vitro. Although this study illustrated that macrophages activated in chronic inflammation have distinct features that cannot be readily reproduced in vitro it also demonstrated that some features of the complex NeMphi phenotype can be replicated by treatment of cultured macrophages with Th2 cytokines. In future, we hope to use in vitro analysis to help define the pathways that lead to this distinctive in vivo macrophage phenotype.

Animals↗
PubMed2006

Content of glycogen and trehalose and activity of alpha-amylase and trehalase in Galleria mellonella larvae infected with entomopathogenic nematodes Steinernema affinis and S. feltiae.

INTRODUCTION: The influence of infection with two species of entomopathogenic nematodes of Steinernematidae family on metabolism of glycogen and trehalose of the host was studied. MATERIAL AND METHODS: Last instar larvae (L7) of Galleria mellonella were experimentally infected with Steinernema affinis and S. feltiae. At 6, 12, 18 and 24 h after infection concentrations of trehalose and glycogen as well as activity of trehalase and alpha-amylase were determined. RESULTS: The content of glycogen was lower in insects infected with S. feltiae than in the controls and animals infected with S. affinis. The content of trehalose was higher in insects from both infected groups than in the controls. Its concentration was slightly higher in larvae infected with S. affinis than in those infected with S. feltiae. The activity of alpha-amylase after infection with S. affinis was low. It was significantly higher in insects infected with S. feltiae. In animals of both infected groups, following a significant reduction at 6 h, the activity of trehalase remained at a similar level, higher than in the controls. In the paper the effects of infection with (i) different species of entomopathogenic nematodes and (ii) the importance of the developmental stage of the insect-host for changes in its metabolism of glycogen and trehalose were discussed.

Animals↗
PubMed1998

A survey of Toxocara infections in cat breeding colonies in The Netherlands.

Faecal samples from 225 adults cats and 112 kittens and dust and soil samples from 25 catteries in the Netherlands were examined for Toxocara eggs. The results of this survey showed a low nematode infection rate in the investigated Dutch catteries since only four adult cats (2%) from two catteries (8%) were found to shed Toxocara cati eggs. No other helminth eggs were seen in the faecal samples. Nematode eggs were not present in the environmental dust and soil samples from houses and kennels; only Dipylidium caninum eggs were found in only two samples of household dust.

Animal Husbandry↗
PubMed2002

Helminth control used by trainers of thoroughbreds in England.

A telephone survey was conducted of the methods used to control parasitic worms at 106 thoroughbred training yards. Most of the horses were allowed access to grass and were therefore at risk of infection. The control methods relied primarily on the use of anthelmintics and appeared reasonably successful because only 44 per cent of trainers reported observing clinical signs of nematode infections. They dosed their horses frequently, 40 per cent treating every four to six weeks and 25 per cent treating every seven to eight weeks. New arrivals on yards were usually treated with anthelmintic but the strategies used would be unlikely to prevent the introduction of anthelmintic-resistant nematodes on most yards or to deal with encysted cyathostomes. Trainers were responsible for the design of most control schemes, and only 42 per cent of them based their choice of anthelmintic on veterinary advice.

Animals↗