Serum Strongylus vulgaris-specific antibody responses to anthelmintic treatment in naturally infected horses (original) (raw)
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Development of Strongylus vulgaris-specific serum antibodies in naturally infected foals
Veterinary Parasitology
Strongylus vulgaris is regarded as the most pathogenic helminth parasite infecting horses. Migrating larvae cause pronounced endarteritis and thrombosis in the cranial mesenteric artery and adjacent branches, and thromboembolism can lead to ischemia and infarction of large intestinal segments. A recently developed serum ELISA allows detection of S. vulgaris-specific antibodies during the six-month-long prepatent period. A population of horses has been maintained at the University of Kentucky without anthelmintic intervention since 1979, and S. vulgaris has been documented to be highly prevalent. In 2012, 12 foals were born in this population, and were studied during a 12-month period (March-March). Weekly serum samples were collected to monitor S. vulgaris specific antibodies with the ELISA. Nine colts underwent necropsy at different time points between 90 and 300 days of age. At necropsy, Strongylus spp. and Parascaris equorum were identified to species and stage and enumerated. In...
Veterinary Parasitology: X
Strongylus vulgaris is considered the most pathogenic nematode parasite of the horse. Frequent deworming programs since the 1970s have reduced the prevalence of S. vulgaris to low levels, but to the price of widespread benzimidazole resistance in the small strongyles (cyathostominae) and ivermectin resistance especially in the equine roundworm Parascaris spp. To slow down the progression of anthelmintic resistance in Sweden, horse anthelmintics were made prescription only medicine in 2007 and selective therapy principles were introduced. This means that only individuals with high egg excretion or clinical signs of helminth infection were treated instead of blanket treatment of all horses on a farm. The aims of this study were to investigate the prevalence and risk factors associated with S. vulgaris infection in Sweden ten years after the introduction of a selective therapy regime. A total of 529 faecal samples from 106 farms were collected during March to June in 2016 and 2017. A web-based questionnaire was used to collect information about deworming routines. Strongyle faecal egg counts (FEC) were performed by McMaster and presence of S. vulgaris was demonstrated with a specific PCR on individual larval cultures. Results were analysed by mixed logistic (S. vulgaris prevalence) or linear (FEC) regression models, where farm was included as random factor. The overall prevalence of S. vulgaris at individual and farm levels was 28% and 61%, respectively. We observed a 2.9 increased odds risk of S. vulgaris infection on farms that based their treatment on strongyle FEC only as compared to farms that complemented strongyle FECs with larval cultures or dewormed regularly, 1-4 times per year, without prior diagnosis. We found no association between the prevalence of S. vulgaris and strongyle FEC level, horse age, geographical region or signs of colic. The prevalence of S. vulgaris was 25% in horses shedding ≤150 eggs per gram. Thus horses with low strongyle FECs that are left untreated could be an important source of S. vulgaris infection. This may be an important reason for the approximately threefold increase in S. vulgaris prevalence since 1999 in Sweden. However, our combined results indicate that selective therapy based on a combination of strongyle FECs and larval cultivation was not associated with an increased risk of S. vulgaris infection. Still, S. vulgaris needs to be monitored continuously and should be taken into careful consideration when the treatment frequency is reduced.
Isolation and characterization of immunodiagnostic antigen from Strongylus vulgaris infecting horses
World applied sciences journal, 2010
Isolation of immunodiagnostic fraction from Strongylus vulgaris adult worms was described by CNBr-Sepharose 4B affinity column chromatography. The isolation process resulted in a fraction with 2161.5 fold increase in binding activity compared to its crude extract. Characterization of the isolated fraction by SDS polyacrylamide gel electrophoresis and isoelectric focusing showed that the fraction consists of only two bands of 39 and 31 KDa with isoelectric points of 6.8 and 6.7. Comparative evaluation of the immunogenic binding activities of the crude extract, unbound and bound fractions by ELISA proved the potency of the bound fraction over the other two antigens. Diagnosis of S. vulgaris infection in horses by ELISA in which the bound fraction was utilized, recorded high infection percentage (73.7) as compared with the parasitological examination (27.6). The isolated fraction in the current study could be utilized successfully in the diagnosis of S. vulgaris infection using ELISA, ...
Strongyle infections and parasitic control strategies in German horses - a risk assessment
BMC veterinary research, 2014
BackgroundAs a consequence of the increasing levels of anthelmintic resistance in cyathostomes, new strategies for equine parasite control are being implemented. To assess the potential risks of these, the occurrence of strongyles was evaluated in a group of 1887 horses. The distribution of fecal egg counts (FECs), the frequency of anthelmintic drug use, and the deworming intervals were also analyzed. Between June 2012 and May 2013, 1887 fecal samples from either selectively or strategically dewormed horses were collected at 195 horse farms all over Germany and analyzed quantitatively with a modified McMaster technique. All samples with FEC ¿20 eggs per gram (EPG) were subjected to coproculture to generate third-stage larvae (LIII) for species differentiation.ResultsEgg counts were below the limit of detection (20 EPG) in 1046 (55.4%) samples and above it in 841 (44.6%) samples. Strongylus vulgaris larvae were identified in two of the 841 positive samples. Infections with cyathostom...
New Perspectives in Equine Intestinal Parasitic Disease: Insights in Monitoring Helminth Infections
The Veterinary clinics of North America. Equine practice, 2018
Regular anthelmintic treatment has contributed to anthelmintic resistance in horse helminths. This mass anthelmintic treatment was originally developed owing to a lack of larvicidal drugs against Strongylus vulgaris. The high prevalence of anthelmintic resistance and shortening of strongyle egg reappearance period after avermectins/moxidectins requires epidemiologically appropriate and sustainable measures. Selective anthelmintic treatment is a much-needed deworming approach: More than 50% of adult horses manifest no strongyle egg excretion. In this article, selective anthelmintic treatment procedure is described, with the specific focus on the advantages of an evidence-based, medically appropriate, and sustainable treatment system that slows the development of anthelmintic resistance.
Parasite Immunology, 2020
Strongylus vulgaris is considered to be the most pathogenic parasite infecting horses. The control of S. vulgaris has during the last decades relied on regular treatments with anthelminthic drugs. However, an emerging anthelminthic resistance observed in other equine nematodes such as the closely related cyathostomins 1,2 has resulted in medical treatment restrictions issued in 2007 by the European Union (2001/82/EG). In the Nordic countries, these restrictions are reported to have contributed to an increased prevalence of S. vulgaris, 3,4 urging for development of alternative methods to control equine parasites. Formulation of vaccines against parasites is a great challenge because of the parasite's complex life cycle and their ability to modulate the host immune response. The life cycle of S. vulgaris involves migration through host tissues by different larval stages. Horses are infected by ingesting infective third stage (L3) larvae on pasture. At this point, the L3s are still encapsulated in their protective second
Veterinary Parasitology, 2014
M.K. Nielsen). a b s t r a c t Migrating Strongylus vulgaris and encysted cyathostomin larvae cause a localized inflam-matory response in horses. It is unknown whether these larvae elicit a systemic acute phase response (APR), evidenced by changes in serum amyloid A (SAA), haptoglobin (Hp), iron (Fe), albumin, or albumin/globulin (A/G) ratio. In this study, 28 horses were randomly allocated to receive either pyrantel tartrate or a pelleted placebo formulation in their daily feed. Concurrent with treatment, all the horses were administered 5000 pyrantel-susceptible cyathostomin infective larvae once daily, 5 days a week, for 24 weeks. Beginning in the fifth week, the horses also received 25 S. vulgaris larvae once weekly for the remainder of the study. At regular biweekly intervals, fecal samples were collected for quantitative egg counts, and whole blood and serum samples were collected for measurement of packed cell volume, total protein, albumin, globulin, A/G ratio, SAA, Hp, and Fe. On days 161-164, all the horses were euthanatized and necropsied. Samples were collected for enumeration of total luminal worm burdens, encysted cyathostomin larval populations, and migrating S. vulgaris larvae. Concentrations of Hp, Fe, and A/G ratio were associated significantly with strongyle burdens. Only treated male horses had significant increases in serum albumin. Larval S. vulgaris did not associate with Fe, whereas Fe was associated negatively with both total cyathostomin burdens and encysted L4s. The A/G ratios differed significantly between the two treatment groups. Significant differences between groups and individual time points were also observed for Hp and Fe, whereas SAA concentrations remained low throughout the study. In general, this study illustrated that experimental inoculations with S. vulgaris and cyathostomins may be associated with changes in Hp, Fe, and serum proteins, but not with SAA. Overall, these changes suggest that mixed strongyle infections elicit a mild acute phase reaction.