F.J. Cortiñas

Ability of the fungus Duddingtonia flagrans to adapt to the cyathostomin egg-output by spreading chlamydospores

The analysis of the capability of the nematode trapping-fungus Duddingtonia flagrans to adapt to the cyathostomin egg-output in horses was evaluated. Fecal samples from 196 pasturing autochthonous Pura Raza Galega horses were collected from the rectum and then divided according to the egg-output into three groups: ≤ 300, 310-800 and >800 eggs per gram feces. Four doses of chlamydospores (0.1, 0.2, 0.4 and 0.8 × 10(6)/100g feces) were directly spread onto fecal pats on the ground, remaining one without treatment as control. Fecal pats confirmed the presence of gastrointestinal nematode larvae belonging to strongylid cyathostomins (Cyathostomum and Gyalocephalus spp). An overall 94% (95% CI 91, 97) percentage of reduction was obtained, and an increase in the activity of the trapping-fungi simultaneously to the rising in the number of cyathostomin eggs and larvae in the coprocultures was detected. A significantly highest reduction of the cyathostomin L3 in the coprocultures with more than 800 EPG was found, which indicates that Df trapping activity is larvae nematode density-dependant. The present research showed the high biological activity of D. flagrans against nematode larvae can adjust to the cyathostomin egg-output, and underlines its efficacy as a practical method for the control of these parasites in grazing horses.

Silvopastoralism and autochthonous equine livestock: analysis of the infection by endoparasites.

Two groups of autochthonous Pura Raza Galega (PRG) horses, one comprising 483 animals under a silvopasturing regime, and the other comprising 72 PRG horses managed in farms, were used to analyse the effect of silvopasture on infection by endoparasites. Results were considered according to the age and the sex of the horses. Faecal samples were individually collected from each animal and analysed by the coprological flotation, sedimentation and migration techniques. Coprocultures were also done to identify the main strongylid genera affecting the horses. Eggs from the gastrointestinal nematoda Parascaris equorum, strongyles and Oxyuris equi were the only endoparasites observed in the faeces of the horses. Larvae of Trichonema and Cyalocephalus spp. (small strongyles) and Strongylus and Triodontophorus (large strongyles) were identified in the coprocultures. The silvopasturing horses had the highest prevalence of the helminth parasites. The percentage of horses passing ascarid eggs was significantly higher in pasturing horses younger than 3 years. The prevalence of strongyles was statistically greater in the oldest grazing equines. Mares reached the highest prevalence of helminth egg output. Our results showed that native horses kept under silvopasture had the highest prevalence of the ascarids, strongyles and oxyurids, possibly due to their exposure to contaminated grazing areas, lack of appropriate feeding and control of their health status. We conclude that silvopasture increases the presence of infection by gastrointestinal nematoda in wild horses, especially by strongyles. Suitable measures to control parasitic diseases affecting horses in silvopasture should be considered in those systems.

AN APPROACH OF THE LABORATORY TO THE FIELD: ASSESSMENT OF THE INFLUENCE OF CATTLE MANAGEMENT ON THE SEROPREVALENCE OF FASCIOLIASIS BY USING POLYCLONAL- AND RECOMBINANT-BASED ELISAs

Abstract A cross-sectional study was conducted to assess the seroprevalence of fascioliasis by immunoenzymatic probes in an endemic area (northwestern Spain). Blood samples were collected from 1,034 cattle (crossbred, Rubia Gallega, and Friesian breeds), and the diagnosis of fascioliasis was carried out by determining both the occurrence of antigenemia and the presence of specific IgG antibodies against a Fasciola hepatica recombinant protein (FhrAPS). The IgG seroprevalence was 65% (95% CI, 62–68) by the FhrAPS-ELISA, and 32% (29–35) exhibited antigenemia; the lowest percentages occurred in the Friesians, and the highest percentages were found in the crossbreds. These results confirm an elevated seroprevalence of fascioliasis that is unexpected considering that most of the cattle livestock (Friesian and Rubia Gallega) receive fasciolicide treatment. The lack of adequate measures on the environment and erratic chemotherapy seem to be responsible for the fact that control of fascioliasis has not improved in the last 10 yr in the area of study.

The efficacy of four anthelmintics against Calicophoron daubneyi in naturally infected dairy cattle

The paramphistomicidal activity of four anthelmintics in dairy cattle naturally infected by Calicophoron (Paramphistomum) daubneyi was evaluated. Seventy Friesian adult cows were treated at drying-off (19 albendazole; 23 netobimin; 13 closantel and 15 oxyclozanide), and 21 remained untreated as controls. The anthelmintic efficacy was determined by estimating the faecal egg count reduction (FECR) values for each of the anthelmintics. The reduction in the number of cows shedding eggs in the faeces was also estimated. The C. daubneyi egg-output was not fully suppressed following the administration of any of the parasiticides. The FECR values ranged from 0% to 26% in the cows receiving albendazole or netobimin, with 11-39% of cattle becoming negative after therapy. Better results were achieved with closantel and oxyclozanide, with FECR values of 97-99% and CPCR (cattle positive by coprology reduction) percentages of 85-93%. The observation of a similar efficacy with closantel and oxyclozanide against C. daubneyi led us to recommend the administration of closantel in those countries where oxyclozanide is not available.

Potential use of Mucor circinelloides for the biological control of certain helminths affecting livestock reared in a care farm

A preliminary study to evaluate the possibilities of biological control procedures against parasites affecting livestock reared in a care farm has been conducted. Adults with mental disabilities were involved in spreading the spores of the filamentous fungus Mucor circinelloides directly onto the faeces, or as a food additive. In the first assay, the spores were sprayed directly onto the faeces of piglets and calves parasitised by roundworms (Ascaris suum) and liver flukes (Fasciola hepatica), respectively. In the second assay, the spores were mixed with on-farm mash feed. Participation of the adults in the experiments was fully satisfactory. In the manure sprayed Mucor spores, the viability of eggs of roundworms and flukes reduced by 53% and 74%, respectively. Significant reductions of viability of eggs of Ascaris (60%) and Fasciola (67%) in the faeces of piglets and calves given mash feed-added Mucor spores were achieved, which demonstrates their ability to survive in the digestive tract of the animals. It is concluded that biological control of parasites could be helpful to decrease the risk of infection in animals reared by intellectually disabled adults in a care farm, and it could motivate them to accomplish new tasks.

Clinical trial of efficacy of ivermectin pour-on against gastrointestinal parasitic nematodes in silvopasturing horses

The aim of this study was to assess, by a clinical trial, the efficacy of an ivermectin-based pour-on treatment against gastrointestinal parasitic nematodes in naturally infected horses using 2 groups of mature indigenous Pura Raza Galega grazing mares. Faecal and blood samples were collected individually over a 21 week period. Faeces were analysed by the coprological flotation, sedimentation and migration techniques. Changes in circulating blood cells were monitored over the study period. The administration of the ivermectin suppressed the egg-elimination of ascarids and pinworms throughout the study and no strongyle-eggs were observed in the treatment group between the 3rd and 10th weeks. The numbers of red cells increased significantly after the anthelmintic therapy, and a statistical reduction in circulating leucocytes was recorded. No side effects were observed. The pour-on ivermectin formulation was highly successful against gastrointestinal nematodes and appears to be a useful therapeutic routine for large groups of horses.

Application of the analysis of serum antibodies (immunoglobulins M and G) to estimate the seroprevalence of ovine oestrosis and to evaluate the effect of chemotherapy.

ABSTRACT The analysis of immunoglobulin (Ig) M and IgG serum isotypes as indicators of the presence of Oestrus ovis developmental stages was carried out. A serological survey to discover the seasonal variations in the prevalence of oestrosis in sheep from an oceanic climate area was developed. Six hundred and sixty-nine blood samples were analyzed for the presence of IgM and IgG using an enzyme-linked immunosorbent assay and O. ovis second-stage larvae excretory/ secretory antigens. In addition, the effect of an ivermectin-based treatment on the humoral immune response was measured. The percentage of positive animals was 54% for IgM and 55% for IgG. The highest percentages of sheep positive to IgM were recorded in the winter and to IgG in the summer. No animals positive to IgM were detected in the ivermectin-treated sheep. These results seem to underline that oestrosis is a parasitic disease to keep watch for in regions with an oceanic climate. A noninvasive evaluation of the success of chemotherapy seems possible by analyzing the serum IgM response.