Strongylus vulgaris

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M K Nielsen - One of the best experts on this subject based on the ideXlab platform.

  • nonstrangulating intestinal infarctions associated with Strongylus vulgaris clinical presentation and treatment outcomes of 30 horses 2008 2016
    Equine Veterinary Journal, 2018
    Co-Authors: Tina H Pihl, S.n. Olsen, M K Nielsen, Pall S Leifsson, Stine Jacobsen
    Abstract:

    Background Strongylus vulgaris is re-emerging in horses kept under surveillance-based parasite control regimens. Information on nonstrangulating intestinal infarction associated with S. vulgaris is needed to improve recognition of the condition. Objective To describe the typical clinical presentation, laboratory findings, gross pathology, treatment and outcome of horses with nonstrangulating intestinal infarction. Study design Retrospective case series. Methods Nonstrangluating intestinal infarction was diagnosed in 30 horses with a localised intestinal infarction with concurrent signs of S. vulgaris migration and no signs of intestinal strangulation or enterocolitis. Data were obtained from medical records in the period 2008-2016. Long-term follow-up information was obtained by telephonic interviews. Levels of S. vulgaris-specific antibodies were retrospectively assessed. Associations between nonstrangulating intestinal infarction and selected variables were evaluated using Fisher's exact and Mann-Whitney U tests. Results The most consistent findings at admission were mild colic of >24 h duration without signs of shock or strangulated intestine, increased peritoneal fluid WBC (>5 × 109 /L), increased serum amyloid A (SAA) concentration and a positive S. vulgaris-specific antibody titre. Medical treatment was attempted in nine horses with none surviving. Exploratory laparotomy was performed in 21 horses. Eleven horses were subjected to euthanasia intraoperatively due to the presumed poor prognosis. Of the nine horses, three (33%) undergoing intestinal resection survived to discharge. The surviving horses were alive and returned to athletic function for at least 2 years following discharge. Main limitations Only nine of the 30 horses underwent resection of the infarcted intestine, and the prognosis for surgical intervention in nonstrangulating intestinal infarction is, therefore, difficult to estimate. Conclusions In areas where S. vulgaris is prevalent, nonstrangulating intestinal infarction should be considered as a differential diagnosis in horses presenting with mild colic and peritonitis. Survival of nonstrangulating intestinal infarction is possible in cases where surgical intervention with resection of the infarcted intestine is feasible. The summary is available in Spanish - see Supporting Information.

  • detection of Strongylus vulgaris in equine faecal samples by real time pcr and larval culture method comparison and occurrence assessment
    BMC Veterinary Research, 2016
    Co-Authors: A Kaspar, M K Nielsen, Kurt Pfister, Cornelia Silaghi, H Fink, Miriam C Scheuerle
    Abstract:

    Strongylus vulgaris has become a rare parasite in Germany during the past 50 years due to the practice of frequent prophylactic anthelmintic therapy. To date, the emerging development of resistance in Cyathostominae and Parascaris spp. to numerous equine anthelmintics has changed deworming management and the frequency of anthelmintic usage. In this regard, reliable detection of parasitic infections, especially of the highly pathogenic S. vulgaris is essential. In the current study, two diagnostic methods for the detection of infections with S. vulgaris were compared and information on the occurrence of this parasite in German horses was gained. For this purpose, faecal samples of 501 horses were screened for S. vulgaris with real-time PCR and an additional larval culture was performed in samples of 278 horses. A subset of 26 horses underwent multiple follow-up examinations with both methods in order to evaluate both the persistence of S. vulgaris infections and the reproducibility of each diagnostic method. The real-time PCR revealed S. vulgaris-DNA in ten of 501 investigated equine samples (1.9%). The larval culture demonstrated larvae of S. vulgaris in three of the 278 samples (1.1%). A direct comparison of the two methods was possible in 321 samples including 43 follow-up examinations with the result of 11 S. vulgaris-positive samples by real-time PCR and 4 S. vulgaris-positive samples by larval culture. The McNemar’s test (p-value = 0.016) revealed a significant difference and the kappa values (0.525) showed a moderate agreement between real-time PCR and larval culture. The real-time PCR detected a significantly higher proportion of positives of S. vulgaris compared to larval culture and should thus be considered as a routine diagnostic method for the detection of S. vulgaris in equine samples.

  • changes in serum Strongylus vulgaris specific antibody concentrations in response to anthelmintic treatment of experimentally infected foals
    Frontiers in Veterinary Science, 2015
    Co-Authors: M K Nielsen, Jennifer L. Bellaw, J A Scare, H S Gravatte, Julio C Prado, Craig R. Reinemeyer
    Abstract:

    Strongylus vulgaris is the most pathogenic nematode parasite of horses. Its extensive migration in the mesenteric blood vessels can lead to life-threatening intestinal infarctions. Recent work has shown that this parasite is still identified among managed horse populations. A serum enzyme-linked immunosorbent assay (ELISA) has been developed for the detection of migrating larvae of S. vulgaris. Previous work has documented an increase in ELISA values following larvicidal treatment with ivermectin and suggested that the target parasite antigen is primarily produced by the later larval stages. The aim of this study was to experimentally inoculate cohorts of foals with S. vulgaris, and then compare ELISA responses to early or later ivermectin treatments. Fifteen foals were held in confinement and infected orally with ~ 25 S. vulgaris third-stage larvae on days 0, 7, 14, and 21. Foals were weaned on Day 43 and turned out to a pasture not previously grazed by horses. Foals remained at pasture continuously until the study was terminated on Day 196. On Day 55, foals were randomly allocated to three treatment groups of five each. Group 1 received ivermectin on Day 56, Group 2 received ivermectin on Day 112, and Group 3 foals served as untreated controls. Serum and fecal samples were collected at 28-day intervals throughout the study. Serum samples were analyzed with the S. vulgaris-specific ELISA and fecal samples were processed for fecal egg counting. The ELISA values of Group 1 foals were significantly lower than Groups 2 or 3 on days 140-196. Both treated groups exhibited increased ELISA values following ivermectin treatment. Results indicate that the target diagnostic antigen is produced throughout the course of arterial infection with S. vulgaris, but that an early ivermectin treatment can reduce the cumulative antigen produced over the course of an infection.

  • effects of daily pyrantel tartrate on strongylid population dynamics and performance parameters of young horses repeatedly infected with cyathostomins and Strongylus vulgaris
    Veterinary Parasitology, 2014
    Co-Authors: Craig R. Reinemeyer, M K Nielsen, U V Andersen, Julio C Prado, B Schricker, T Kennedy
    Abstract:

    Strongylid infections are ubiquitous in grazing horse populations. Infections with cyathostomin (small strongyle) and strongylin (large strongyle) nematodes have long been associated with clinical disease in horses, but little is known about their subclinical impact. A masked, randomized, controlled study was conducted to evaluate the effects of daily administration of pyrantel tartrate on body condition scores, weight gain, fecal egg counts, and total worm counts of young horses repeatedly inoculated with strongylid larvae. Twenty eight immature horses were treated with larvicidal anthelmintic regimens and randomly allocated to two groups. Group 1 horses were given a pelleted placebo product once daily, and those in Group 2 received pyrantel tartrate once daily at ∼ 2.64 mg/kg body weight. On five days during each week, ∼ 5000 infective cyathostomin larvae were administered to each horse. In addition, horses received ∼ 25 infective Strongylus vulgaris larvae once weekly. Horses were maintained on pasture for 154 days and had ad libitum access to grass hay throughout. At approximate, 14-day intervals, body weights were measured, body condition scores were assigned, fecal samples were collected for egg counts, and blood samples were collected for measurement of S. vulgaris antibodies and various physiologic parameters. After 22 weeks at pasture and 14-17 days in confinement, horses were euthanatized and necropsied. Nematodes were recovered and counted from aliquots of organ contents, representative samples of large intestinal mucosa, and the root of the cranial mesenteric artery. Daily treatment with pyrantel tartrate at the recommended dosage significantly reduced numbers of adult cyathostomins in the gut lumen and early third-stage larvae in the cecal mucosa, increased the proportions of fourth-stage larvae in the gut contents, and was accompanied by significant improvements in body condition scores. Fecal egg counts of horses receiving daily pyrantel tartrate were significantly reduced, with percentages of efficacy ranging from 84.4% to 98.9%, but egg counts of both groups increased significantly over the course of the study. Treatment also significantly reduced the numbers of S. vulgaris larvae in the cranial mesenteric artery by 99.2%. Serum antibodies to S. vulgaris apparently persisted from pre-enrollment infections, but ELISA values gradually declined over the course of the study. This study has provided useful insights into the effects of daily pyrantel tartrate on the dynamics of cyathostomin infection, and into some subclinical effects of strongylid parasitism in horses.

  • physiologic and systemic acute phase inflammatory responses in young horses repeatedly infected with cyathostomins and Strongylus vulgaris
    Veterinary Parasitology, 2014
    Co-Authors: U V Andersen, Stine Jacobsen, S.n. Olsen, Craig R. Reinemeyer, Nils Toft, M K Nielsen
    Abstract:

    Abstract Migrating Strongylus vulgaris and encysted cyathostomin larvae cause a localized inflammatory 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.

Martin K. Nielsen - One of the best experts on this subject based on the ideXlab platform.

  • diagnosing Strongylus vulgaris in pooled fecal samples
    Veterinary Parasitology, 2021
    Co-Authors: Martin K. Nielsen, Chelsea Facison, Jessica A Scare, Avery N Martin, Holli S Gravatte, Ashley E Steuer
    Abstract:

    Abstract Strongylus vulgaris is the most pathogenic intestinal helminth parasite infecting horses. The migrating larvae in the mesenteric blood vessels can cause non-strangulating intestinal infarctions, which have a guarded prognosis for survival. Infections are typically diagnosed by coproculture, but a PCR test is available in some countries. While it is ideal to test horses individually, many veterinarians and clients wish to pool samples to reduce workload and cost of the diagnostic method. The purpose of this study was to determine if pooling of fecal samples would negatively impact diagnostic performance of the coproculture and the PCR for determination of S. vulgaris infection. Ten horses with strongylid eggs per gram (EPG) >500 and confirmed as either S. vulgaris positive or negative were selected as fecal donors. Eight pools with feces from five horses were created with 0%, 10 %, 20 %, 30 %, 40 %, 50 %, 80 %, and 100 % S. vulgaris positive feces. From each pool, 20 subsamples of 10 g each were collected and analyzed. Half of these samples were set up for coproculture and the other half for PCR. All pools containing 50 % or greater S. vulgaris positive feces were detected positive by both PCR and coproculture. In the pools with less than 50 % S. vulgaris positive feces, the PCR detected 33 positive samples compared to 24 with the coproculture. Three samples from the 0% pool were detected as low-level PCR positives, but this could be due to contamination. These results indicate that diagnosing S. vulgaris on pooled samples is reliable, when at least 50 % of the feces in a pool are from S. vulgaris positive animals. Since S. vulgaris remains relatively rare in managed horses, however, some diagnostic sensitivity is expected to be lost with a pooled sample screening approach. Nonetheless, pooled sample screening on farms could still be considered useful under some circumstances, and the PCR generally performed better at the lower proportions of S. vulgaris positive feces.

  • Changes in Hemostatic Indices in Foals Naturally Infected With Strongylus vulgaris
    Journal of Equine Veterinary Science, 2017
    Co-Authors: Tina H Pihl, Martin K. Nielsen, Stine Jacobsen
    Abstract:

    Abstract Strongylus vulgaris has been found endemic in equine populations subject to parasite control by targeted selective anthelmintic therapy. This study investigated hemostasis in foals naturally infected with S. vulgaris and monitored this response over the course of progressing infection stages. The hemostatic indices D-dimer, antithrombin III (ATIII), fibrinogen, prothrombin time (PT), and activated partial thromboplastin time were evaluated in weekly blood samples for up to 50 weeks in 12 foals born into a herd with high prevalence of S. vulgaris . Results were compared with weekly S. vulgaris antibody enzyme-linked immunosorbent assay values in all foals using a linear mixed effects model with repeated measures and to total numbers of S. vulgaris larvae in nine foals at necropsy with Pearson linear correlation. In the first week of life, all evaluated indices of hemostasis were significantly different from those observed in the rest of the study weeks, corresponding to previously demonstrated aberrancies in neonates. Significant changes were seen for D-dimer in weeks 11–24, 26–27, 30, and 39 compared with week 2, for PT in weeks 12–13 compared with week 6, and for ATIII in week 15 compared with week 4. Strongylus vulgaris antibody levels were statistically associated with D-dimer ( P = .0076) and fibrinogen ( P = .0004) concentrations. Naturally acquired infection with S. vulgaris was associated with changes suggestive of mild activation of coagulation, fibrinolysis, and inflammation. The results of this study may help elucidate the pathogenesis of the endarteritis, thromboembolism, and nonstrangulating intestinal ischemia that is observed in horses with S. vulgaris infection.

  • Evaluation of Baermann apparatus sedimentation time on recovery of Strongylus vulgaris and S. edentatus third stage larvae from equine coprocultures
    Veterinary Parasitology, 2015
    Co-Authors: Jennifer L. Bellaw, Martin K. Nielsen
    Abstract:

    Abstract Traditional methods of diagnosing equine Strongylinae infections require culturing feces, sedimenting the culture media in Baermann apparatuses, collecting the sediment, and morphologically identifying recovered third stage larvae. However, this method is plagued by low negative predictive values. This study evaluated sedimentation time within the Baermann apparatus by comparing larval recovery from the traditionally collected sediment, “sediment 1”, and from the usually discarded remaining fluid contents, “sediment 2”, of the Baermann apparatus after 12, 24, and 48 h. A grand total of 147,482 larvae were recovered and examined. Sedimentation time did not significantly influence total larval recovery. At all three durations, significantly more Cyathostominae and Strongylus vulgaris larvae were covered from sediment 1 than from sediment 2. However, less than 60% of all recovered Strongylus edentatus were recovered from sediment 1. As 95% of S. vulgaris larvae were always recovered from sediment 1, the need for collection and examination of the remaining fluid contents of the Baermann apparatus is obviated when performing coprocultures for diagnosis of S. vulgaris infections, and sedimentation for 12 h is adequate. Approximately 70% of Cyathostominae were recovered in sediment 1 at all durations, suggesting that 12 h of sedimentation is adequate, although there is a need for future research to evaluate the risk of selection bias at differing sedimentation times among individual cyathostomin species. In contrast to S. vulgaris , collecting and examining the entire contents of the Baermann apparatus may be necessary when an increased diagnostic sensitivity and negative predictive value is desired in diagnosing S. edentatus infections as only 38–61% of larvae were recovered from sediment 1 portion of the Baermann apparatus. This information will allow researchers and practitioners to make more informed decisions in choosing appropriate larval recovery techniques, balancing recovery, time, and effort.

  • Nonstrangulating intestinal infarction associated with Strongylus vulgaris in referred Danish equine cases.
    Equine veterinary journal, 2015
    Co-Authors: Martin K. Nielsen, Stine Jacobsen, S.n. Olsen, E. Bousquet, Tina H Pihl
    Abstract:

    SummaryReasons for performing study Strongylus vulgaris is a pathogenic helminth parasite infecting horses and was once considered to be the primary cause of colic. Migrating larvae cause ischaemia and infarction of intestinal segments. This knowledge is derived from case reports and experimental inoculations of parasite-naive foals, and it remains unknown to what extent the parasite is associated with different types of colic. Objectives To evaluate the role of S. vulgaris as a risk factor for different types of colic in horses. Study design A retrospective case–control study among horses referred with abdominal pain to the University of Copenhagen Large Animal Teaching Hospital during 2009–2011. Methods Each colic case was matched with an equid of the same type (pony, Warmblooded or Coldblooded), age, sex and admitted in the same month and year but for problems unrelated to the gastrointestinal tract. Serum samples were analysed for antibodies to migrating S. vulgaris larvae using a recently developed enzyme-linked immunosorbent assay (ELISA). The following 4 case definitions were used: colic sensu lato, i.e. all horses presenting with colic (n = 274), with further subgroups, i.e. undiagnosed colics (n = 48), strangulating obstructions (n = 76) and nonstrangulating infarctions (n = 20). Results Strongylus vulgaris antibody levels were similar to control values in colics sensu lato and horses with undiagnosed colic. In contrast, nonstrangulating intestinal infarctions were significantly associated with positive S. vulgaris ELISAs (odds ratio 5.33, 95% confidence interval 1.03–27.76, P = 0.05). Also, horses with nonstrangulating infarctions had a significantly higher occurrence of positive ELISAs than horses with strangulating obstructions (odds ratio 3.79, 95% confidence interval 1.34–10.68, P = 0.01) and the colic sensu lato group (odds ratio 3.09, 95% confidence interval 1.20–8.01, P = 0.02). Conclusions Nonstrangulating intestinal infarction was strongly associated with S. vulgaris-specific antibodies, whereas the more broadly defined colic categories were not associated with positive ELISA results. Thus, the ELISA holds potential to become a helpful adjunct in diagnosis and management of horses with colic. The Summary is available in Chinese – see Supporting information.

  • Serum Strongylus vulgaris-specific antibody responses to anthelmintic treatment in naturally infected horses
    Parasitology Research, 2015
    Co-Authors: Martin K. Nielsen, Holli S Gravatte, Anand N. Vidyashankar, Jennifer Bellaw, Xin Cao, Emily F. Rubinson, Craig R. Reinemeyer
    Abstract:

    Strongylus vulgaris is the most pathogenic helminth parasite of horses, causing verminous endarteritis with thromboembolism and infarction. A serum enzyme-linked immunosorbent assay (ELISA) has been validated for detection of antibodies to an antigen produced by migrating larvae of this parasite. The aim was to evaluate ELISA responses to anthelmintic treatment in cohorts of naturally infected horses. Fifteen healthy horses harboring patent S. vulgaris infections were turned out for communal grazing in May 2013 (day 0). On day 55, horses were ranked according to ELISA titers and randomly allocated to the following three groups: no treatment followed by placebo pellets daily; ivermectin on day 60 followed by placebo pellets daily; or ivermectin on day 60 followed by daily pyrantel tartrate. Fecal and serum samples were collected at ∼28-day intervals until study termination on day 231. Increased ELISA values were observed for the first 53 days following ivermectin treatment. Titers were significantly reduced 80 days after ivermectin treatment. Horses receiving daily pyrantel tartrate maintained lower ELISA values from 137 days post ivermectin treatment until trial termination. These results illustrate that a positive ELISA result is indicative of either current or prior exposure to larval S. vulgaris infection within the previous 5 months.

S.n. Olsen - One of the best experts on this subject based on the ideXlab platform.

  • nonstrangulating intestinal infarctions associated with Strongylus vulgaris clinical presentation and treatment outcomes of 30 horses 2008 2016
    Equine Veterinary Journal, 2018
    Co-Authors: Tina H Pihl, S.n. Olsen, M K Nielsen, Pall S Leifsson, Stine Jacobsen
    Abstract:

    Background Strongylus vulgaris is re-emerging in horses kept under surveillance-based parasite control regimens. Information on nonstrangulating intestinal infarction associated with S. vulgaris is needed to improve recognition of the condition. Objective To describe the typical clinical presentation, laboratory findings, gross pathology, treatment and outcome of horses with nonstrangulating intestinal infarction. Study design Retrospective case series. Methods Nonstrangluating intestinal infarction was diagnosed in 30 horses with a localised intestinal infarction with concurrent signs of S. vulgaris migration and no signs of intestinal strangulation or enterocolitis. Data were obtained from medical records in the period 2008-2016. Long-term follow-up information was obtained by telephonic interviews. Levels of S. vulgaris-specific antibodies were retrospectively assessed. Associations between nonstrangulating intestinal infarction and selected variables were evaluated using Fisher's exact and Mann-Whitney U tests. Results The most consistent findings at admission were mild colic of >24 h duration without signs of shock or strangulated intestine, increased peritoneal fluid WBC (>5 × 109 /L), increased serum amyloid A (SAA) concentration and a positive S. vulgaris-specific antibody titre. Medical treatment was attempted in nine horses with none surviving. Exploratory laparotomy was performed in 21 horses. Eleven horses were subjected to euthanasia intraoperatively due to the presumed poor prognosis. Of the nine horses, three (33%) undergoing intestinal resection survived to discharge. The surviving horses were alive and returned to athletic function for at least 2 years following discharge. Main limitations Only nine of the 30 horses underwent resection of the infarcted intestine, and the prognosis for surgical intervention in nonstrangulating intestinal infarction is, therefore, difficult to estimate. Conclusions In areas where S. vulgaris is prevalent, nonstrangulating intestinal infarction should be considered as a differential diagnosis in horses presenting with mild colic and peritonitis. Survival of nonstrangulating intestinal infarction is possible in cases where surgical intervention with resection of the infarcted intestine is feasible. The summary is available in Spanish - see Supporting Information.

  • Nonstrangulating intestinal infarction associated with Strongylus vulgaris in referred Danish equine cases.
    Equine veterinary journal, 2015
    Co-Authors: Martin K. Nielsen, Stine Jacobsen, S.n. Olsen, E. Bousquet, Tina H Pihl
    Abstract:

    SummaryReasons for performing study Strongylus vulgaris is a pathogenic helminth parasite infecting horses and was once considered to be the primary cause of colic. Migrating larvae cause ischaemia and infarction of intestinal segments. This knowledge is derived from case reports and experimental inoculations of parasite-naive foals, and it remains unknown to what extent the parasite is associated with different types of colic. Objectives To evaluate the role of S. vulgaris as a risk factor for different types of colic in horses. Study design A retrospective case–control study among horses referred with abdominal pain to the University of Copenhagen Large Animal Teaching Hospital during 2009–2011. Methods Each colic case was matched with an equid of the same type (pony, Warmblooded or Coldblooded), age, sex and admitted in the same month and year but for problems unrelated to the gastrointestinal tract. Serum samples were analysed for antibodies to migrating S. vulgaris larvae using a recently developed enzyme-linked immunosorbent assay (ELISA). The following 4 case definitions were used: colic sensu lato, i.e. all horses presenting with colic (n = 274), with further subgroups, i.e. undiagnosed colics (n = 48), strangulating obstructions (n = 76) and nonstrangulating infarctions (n = 20). Results Strongylus vulgaris antibody levels were similar to control values in colics sensu lato and horses with undiagnosed colic. In contrast, nonstrangulating intestinal infarctions were significantly associated with positive S. vulgaris ELISAs (odds ratio 5.33, 95% confidence interval 1.03–27.76, P = 0.05). Also, horses with nonstrangulating infarctions had a significantly higher occurrence of positive ELISAs than horses with strangulating obstructions (odds ratio 3.79, 95% confidence interval 1.34–10.68, P = 0.01) and the colic sensu lato group (odds ratio 3.09, 95% confidence interval 1.20–8.01, P = 0.02). Conclusions Nonstrangulating intestinal infarction was strongly associated with S. vulgaris-specific antibodies, whereas the more broadly defined colic categories were not associated with positive ELISA results. Thus, the ELISA holds potential to become a helpful adjunct in diagnosis and management of horses with colic. The Summary is available in Chinese – see Supporting information.

  • physiologic and systemic acute phase inflammatory responses in young horses repeatedly infected with cyathostomins and Strongylus vulgaris
    Veterinary Parasitology, 2014
    Co-Authors: U V Andersen, Stine Jacobsen, S.n. Olsen, Craig R. Reinemeyer, Nils Toft, M K Nielsen
    Abstract:

    Abstract Migrating Strongylus vulgaris and encysted cyathostomin larvae cause a localized inflammatory 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.

  • svsxp a Strongylus vulgaris antigen with potential for prepatent diagnosis
    Parasites & Vectors, 2013
    Co-Authors: Ulla V Andersen, S.n. Olsen, Craig R. Reinemeyer, Daniel K Howe, Sriveny Dangoudoubiyam, Nils Toft, Jesper Monrad, Peter Nejsum, E T Lyons, Martin K. Nielsen
    Abstract:

    Strongyle parasites are ubiquitous in grazing horses. Strongylus vulgaris, the most pathogenic of the large strongyles, is known for its extensive migration in the mesenteric arterial system. The lifecycle of S. vulgaris is characterised by a long prepatent period where the migrating larvae are virtually undetectable as there currently is no test available for diagnosing prepatent S. vulgaris infection. Presence of S. vulgaris larvae in the arterial system causes endarteritis and thrombosis with a risk of non-strangulating intestinal infarctions. Emergence of anthelmintic resistance among cyathostomins has led to recommendations of reduced treatment intensity by targeting horses that exceed a predetermined strongyle faecal egg count threshold. One study suggests an apparent increase in prevalence of S. vulgaris on farms where reduced anthelmintic treatment intensity has been implemented. These issues highlight the need for an accurate and reliable assay for diagnosing prepatent S. vulgaris infection. Immunoscreening of a larval S. vulgaris cDNA library using hyperimmune serum raised against S. vulgaris excretory/secretory antigens was performed to identify potential diagnostic antigens. Immunoreactive clones were sequenced, one potential antigen was characterised, expressed as a recombinant protein, initially evaluated by western blot (WB) analysis, the diagnostic potential of the IgG subclasses was evaluated by ELISA, and the diagnostic accuracy evaluated using serum from 102 horses with known S. vulgaris infection status. The clone expressing the potential antigen encoded a S. vulgaris SXP/RAL2 homologue. The recombinant protein, rSvSXP, was shown to be a potential diagnostic antigen by WB analysis, and a target of serum IgGa, IgG(T) and total IgG in naturally infected horses, with IgG(T) antibodies being the most reliable indicator of S. vulgaris infection in horses. Evaluation of diagnostic accuracy of the ELISA resulted in a sensitivity of 73.3%, a specificity of 81.0%, a diagnostic odds ratio of 11.69; a positive likelihood ratio (LR) of 3.85 and a negative LR was 0.33. The area under the ROC curve was 0.820. IgG(T) antibodies to recombinant SvSXP show potential for use as an antigen for prepatent diagnosis of migrating stages of S. vulgaris with moderate to good diagnostic accuracy.

  • Real-time PCR evaluation of Strongylus vulgaris in horses on farms in Denmark and Central Kentucky.
    Veterinary parasitology, 2012
    Co-Authors: M K Nielsen, S.n. Olsen, E T Lyons, J Monrad, Stig Milan Thamsborg
    Abstract:

    Strongyle parasites are ubiquitous in grazing horses, and the large strongyle Strongylus vulgaris is considered the most pathogenic helminth parasite of horses. Recent investigations have suggested an association between occurrence of this parasite and usage of selective therapy based on regular fecal egg counts. The established diagnostic method for S. vulgaris involves larval culture and subsequent morphological identification of third stage larvae under the microscope. Recently, a real-time PCR assay was developed and validated for the detection and semi-quantification of S. vulgaris eggs in equine fecal samples. The purposes of the present study were (a) to determine the presence of S. vulgaris by real-time PCR in Danish and American horses on farms using vastly different anthelmintic treatment regimens and (b) to evaluate the association between larval culture results and the PCR. A total of 991 horses representing 53 different horse farms in Denmark and Central Kentucky were studied. Fresh fecal samples were collected from all horses, and strongyle eggs retrieved for DNA extraction and subsequent real-time PCR analysis. Individual larval cultures were performed on the Danish part of the data set (663 horses on 42 farms). On the Danish farms, the S. vulgaris PCR prevalence was found to be 9.2% on farms not basing parasite control on fecal egg counts, and 14.1% on farms using selective therapy. No horses were PCR positive in the American part of the study (328 horses on 11 farms). Kappa-values indicated a moderate agreement between PCR and larval culture results, while McNemar tests revealed no statistical difference between the paired proportions. Significant associations were found between PCR cycle of threshold (Ct) value groups and larval culture counts. Results indicate that both diagnostic methods can be useful for determining the occurrence of S. vulgaris on horse farms, but that they both are affected by potential sources of error. The PCR results confirmed previous findings suggesting that S. vulgaris can reemerge under selective therapy regimens.

Stine Jacobsen - One of the best experts on this subject based on the ideXlab platform.

  • nonstrangulating intestinal infarctions associated with Strongylus vulgaris clinical presentation and treatment outcomes of 30 horses 2008 2016
    Equine Veterinary Journal, 2018
    Co-Authors: Tina H Pihl, S.n. Olsen, M K Nielsen, Pall S Leifsson, Stine Jacobsen
    Abstract:

    Background Strongylus vulgaris is re-emerging in horses kept under surveillance-based parasite control regimens. Information on nonstrangulating intestinal infarction associated with S. vulgaris is needed to improve recognition of the condition. Objective To describe the typical clinical presentation, laboratory findings, gross pathology, treatment and outcome of horses with nonstrangulating intestinal infarction. Study design Retrospective case series. Methods Nonstrangluating intestinal infarction was diagnosed in 30 horses with a localised intestinal infarction with concurrent signs of S. vulgaris migration and no signs of intestinal strangulation or enterocolitis. Data were obtained from medical records in the period 2008-2016. Long-term follow-up information was obtained by telephonic interviews. Levels of S. vulgaris-specific antibodies were retrospectively assessed. Associations between nonstrangulating intestinal infarction and selected variables were evaluated using Fisher's exact and Mann-Whitney U tests. Results The most consistent findings at admission were mild colic of >24 h duration without signs of shock or strangulated intestine, increased peritoneal fluid WBC (>5 × 109 /L), increased serum amyloid A (SAA) concentration and a positive S. vulgaris-specific antibody titre. Medical treatment was attempted in nine horses with none surviving. Exploratory laparotomy was performed in 21 horses. Eleven horses were subjected to euthanasia intraoperatively due to the presumed poor prognosis. Of the nine horses, three (33%) undergoing intestinal resection survived to discharge. The surviving horses were alive and returned to athletic function for at least 2 years following discharge. Main limitations Only nine of the 30 horses underwent resection of the infarcted intestine, and the prognosis for surgical intervention in nonstrangulating intestinal infarction is, therefore, difficult to estimate. Conclusions In areas where S. vulgaris is prevalent, nonstrangulating intestinal infarction should be considered as a differential diagnosis in horses presenting with mild colic and peritonitis. Survival of nonstrangulating intestinal infarction is possible in cases where surgical intervention with resection of the infarcted intestine is feasible. The summary is available in Spanish - see Supporting Information.

  • Changes in Hemostatic Indices in Foals Naturally Infected With Strongylus vulgaris
    Journal of Equine Veterinary Science, 2017
    Co-Authors: Tina H Pihl, Martin K. Nielsen, Stine Jacobsen
    Abstract:

    Abstract Strongylus vulgaris has been found endemic in equine populations subject to parasite control by targeted selective anthelmintic therapy. This study investigated hemostasis in foals naturally infected with S. vulgaris and monitored this response over the course of progressing infection stages. The hemostatic indices D-dimer, antithrombin III (ATIII), fibrinogen, prothrombin time (PT), and activated partial thromboplastin time were evaluated in weekly blood samples for up to 50 weeks in 12 foals born into a herd with high prevalence of S. vulgaris . Results were compared with weekly S. vulgaris antibody enzyme-linked immunosorbent assay values in all foals using a linear mixed effects model with repeated measures and to total numbers of S. vulgaris larvae in nine foals at necropsy with Pearson linear correlation. In the first week of life, all evaluated indices of hemostasis were significantly different from those observed in the rest of the study weeks, corresponding to previously demonstrated aberrancies in neonates. Significant changes were seen for D-dimer in weeks 11–24, 26–27, 30, and 39 compared with week 2, for PT in weeks 12–13 compared with week 6, and for ATIII in week 15 compared with week 4. Strongylus vulgaris antibody levels were statistically associated with D-dimer ( P = .0076) and fibrinogen ( P = .0004) concentrations. Naturally acquired infection with S. vulgaris was associated with changes suggestive of mild activation of coagulation, fibrinolysis, and inflammation. The results of this study may help elucidate the pathogenesis of the endarteritis, thromboembolism, and nonstrangulating intestinal ischemia that is observed in horses with S. vulgaris infection.

  • Nonstrangulating intestinal infarction associated with Strongylus vulgaris in referred Danish equine cases.
    Equine veterinary journal, 2015
    Co-Authors: Martin K. Nielsen, Stine Jacobsen, S.n. Olsen, E. Bousquet, Tina H Pihl
    Abstract:

    SummaryReasons for performing study Strongylus vulgaris is a pathogenic helminth parasite infecting horses and was once considered to be the primary cause of colic. Migrating larvae cause ischaemia and infarction of intestinal segments. This knowledge is derived from case reports and experimental inoculations of parasite-naive foals, and it remains unknown to what extent the parasite is associated with different types of colic. Objectives To evaluate the role of S. vulgaris as a risk factor for different types of colic in horses. Study design A retrospective case–control study among horses referred with abdominal pain to the University of Copenhagen Large Animal Teaching Hospital during 2009–2011. Methods Each colic case was matched with an equid of the same type (pony, Warmblooded or Coldblooded), age, sex and admitted in the same month and year but for problems unrelated to the gastrointestinal tract. Serum samples were analysed for antibodies to migrating S. vulgaris larvae using a recently developed enzyme-linked immunosorbent assay (ELISA). The following 4 case definitions were used: colic sensu lato, i.e. all horses presenting with colic (n = 274), with further subgroups, i.e. undiagnosed colics (n = 48), strangulating obstructions (n = 76) and nonstrangulating infarctions (n = 20). Results Strongylus vulgaris antibody levels were similar to control values in colics sensu lato and horses with undiagnosed colic. In contrast, nonstrangulating intestinal infarctions were significantly associated with positive S. vulgaris ELISAs (odds ratio 5.33, 95% confidence interval 1.03–27.76, P = 0.05). Also, horses with nonstrangulating infarctions had a significantly higher occurrence of positive ELISAs than horses with strangulating obstructions (odds ratio 3.79, 95% confidence interval 1.34–10.68, P = 0.01) and the colic sensu lato group (odds ratio 3.09, 95% confidence interval 1.20–8.01, P = 0.02). Conclusions Nonstrangulating intestinal infarction was strongly associated with S. vulgaris-specific antibodies, whereas the more broadly defined colic categories were not associated with positive ELISA results. Thus, the ELISA holds potential to become a helpful adjunct in diagnosis and management of horses with colic. The Summary is available in Chinese – see Supporting information.

  • physiologic and systemic acute phase inflammatory responses in young horses repeatedly infected with cyathostomins and Strongylus vulgaris
    Veterinary Parasitology, 2014
    Co-Authors: U V Andersen, Stine Jacobsen, S.n. Olsen, Craig R. Reinemeyer, Nils Toft, M K Nielsen
    Abstract:

    Abstract Migrating Strongylus vulgaris and encysted cyathostomin larvae cause a localized inflammatory 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.

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  • Frilevande larver av Strongylus vulgaris
    2020
    Co-Authors: Ling Julia
    Abstract:

    Den stora blodmasken, Strongylus vulgaris, drabbar hästar på betet. Parasiten har en fekal-oral livscykel som tar ca sex månader att fullborda. Infekterade individer sprider ägg från S. vulgaris via träcken, varpå äggen kläcks och larver utvecklas i träckhögen på betet. Då S. vulgaris utvecklats till det infektiösa larvstadiet, L3-stadiet, kan parasiten smitta nya individer. Den fortsatta parasitära utvecklingen sker sedan i hästens digestionskanal samt intilliggande kärl. De skador som S. vulgaris larver orsakar innan de utvecklats till adulta maskar i hästens grovtarm kan skapa en rad olika hälsoproblem. Den kliniska betydelsen av skadorna beror på dess omfattning och lokalisation, vilket ger upphov till en bred symptombild med allt från symptomlöshet till kolik och peritonit. S. vulgaris har ökat kraftigt bland svenska hästbesättningar de senaste åren, något som tycks bero på utebliven diagnostik och således utebliven behandling av infekterade individer. I dagsläget finns inga tillgängliga studier som visat hur frilevande larver av S. vulgaris beter sig på betet. Studier av små blodmaskar, cyathostominae, samt blandade populationer av blodmaskar har studerats. Det har då antagits att de båda arterna av blodmaskar uppträder på liknande vis gällande överlevnad samt övervintring på betet. Infektiösa larvstadier av cyathostominae kontaminerar beten genom att migrera från träckhögen ut i den omgivande vegetationen, vilket kan påvisas genom att provta gräs från kontaminerade beten. I vilken omfattning S. vulgaris migrerar från träckhögen och hur snabbt smittrycket byggs upp är ännu inte klarlagt. Syftet med den här deskriptiva studien är att få mer kunskap om hur S. vulgaris larver smittar ett bete, samt hur länge smittan finns kvar på betet. Studien har delats upp i tre delstudier. I delstudie 1 undersöktes hur länge larver av S. vulgaris överlever på betet, samt om det är möjligt att detektera betessmitta genom gräsprover. I delstudie 2 studerades smittrycket från S. vulgaris larver och hur långt de migrerar från träckhögar som deponerats på en gräsyta under våren. I delstudie 3 undersöktes kläckning av ägg från S. vulgaris, samt larvers smitttryck och migration till den omgivande vegetationen från träckhögar som deponerats på en gräsyta under hösten. För att besvara frågeställningar i de olika delstudierna togs gräsprov, träckprov och även jordprov (endast i delstudie 1 och 2) vid upprepade tillfällen under sommaren och hösten år 2019. Samtliga prover analyserades sedan för detektion och kvantifiering av L3-larver av S. vulgaris. Resultatet visar att den största smittreservoaren på betet är träckhögarna. Studien visar också att det tar fyra veckor för L3-larver att utvecklas på betet då träckhögar deponeras på en gräsyta på hösten. S. vulgaris kan återfinnas i gräsprov från smittade beten, men parasiten tycks migrera i mycket låg omfattning till den omgivande vegetationen. Att använda gräsprov för att detektera förekomst av S. vulgaris på ett bete är därför ingen bra diagnostisk metod. Då träckhögar fungerar som en reservoar för smitta kan mockning av hagar utgöra ett bra komplement till läkemedel för att reducera smittan från betet. Längre studier med mer frekventa provtagningar är nödvändigt för att fastställa hur S. vulgaris överlever, övervintrar samt migrerar i beteshagen.The large strongyle, Strongylus vulgaris, is a common endoparasite in grazing horses. The parasite has a fecal-oral life cycle, which takes six months to complete. Infected horses spread eggs from S. vulgaris to the pasture with feces. The eggs hatch and develop into larvae the third stage larvae (L3) on pasture and are ingested by grazing horses. The larvae then continue to develop through somatic migration in the horse’s intestines and arteries of the intestine, where they cause lesions in blood vessels, which can be associated with thrombosis, and ischemic lesions of the intestine. The clinical significance of the parasite-induced lesions depend on their magnitude and location. Infected horses can therefor show a broad spectrum of clinical signs including no symptoms to colic and peritonitis. The prevalence of S. vulgaris has increased during the last centuries in Sweden, probably due to the fact that S. vulgaris diagnostics is not always included in the parasite monitoring programme and therefore a risk that low egg shedding horses are left untreated. There are no available studies today explaining the behaviour of free living larvae of S. vulgaris on pasture. In studies of small strongyles, cyathostominae, it has been assumed that small strongyles and S. vulgaris behave in a similar way in terms of survival, migration pattern and overwintering on pasture. Infectious larval stages of cyathostominae contaminate pasture by migrating from feacal patches to the surrounding vegetation. This can be observered by sampling grass from contaminated areas. The extent of how S. vulgaris migrates from the feacal patch and how the infection increases on pasture has not yet been determined. The aim of this descriptive study is to gain more knowledge about how free-living larvae of S. vulgaris infect a pasture and how long the infection remains on contaminated areas. The study has been divided into three minor studies. In study 1, we investigated how long free living stages of S. vulgaris survives on pasture and whether it is possible to detect infection on pasture with grass samples. In the second study, the infection pressure from larvae of S. vulgaris was studied and how and when the larvae migrate from the feacal patch deposited on pasture during the spring. In the third study the hatching of eggs from S. vulgaris was studied, as well as larval infection pressure and migration to surrounding vegetation from feacal patch deposited on pasture during the autumn. To answer the questions, samples from grass, feces and soil were collected repeatedly during the summer and autumn of 2019. All samples were analysed for detection and quantification of third stage larvae of S. vulgaris. The results of this study show that the greatest reservoir on pasture are the feacal patches. The study also shows that S. vulgaris larvae migrate from the feacal pach to the surrounding vegatation to a low extent. Manual removal of feces from pasture is therefore a good alternative to anthelmintic drugs to reduce pasture contamination. Grass samples on pasture needs to be complimented with samples from the feacal patches to detect the presence of S. vulgaris in pasture. These preliminary data need to be further evaluated with longer studies and more frequent sampling to determine how S. vulgaris survives, overwinters and migrate on pasture

  • Free living larvae of Strongylus vulgaris : an experimental study
    SLU Dept. of Biomedical Sciences and Veterinary Public Health, 2020
    Co-Authors: Ling Julia
    Abstract:

    Den stora blodmasken, Strongylus vulgaris, drabbar hästar på betet. Parasiten har en fekal-oral livscykel som tar ca sex månader att fullborda. Infekterade individer sprider ägg från S. vulgaris via träcken, varpå äggen kläcks och larver utvecklas i träckhögen på betet. Då S. vulgaris utvecklats till det infektiösa larvstadiet, L3-stadiet, kan parasiten smitta nya individer. Den fortsatta parasitära utvecklingen sker sedan i hästens digestionskanal samt intilliggande kärl. De skador som S. vulgaris larver orsakar innan de utvecklats till adulta maskar i hästens grovtarm kan skapa en rad olika hälsoproblem. Den kliniska betydelsen av skadorna beror på dess omfattning och lokalisation, vilket ger upphov till en bred symptombild med allt från symptomlöshet till kolik och peritonit. S. vulgaris har ökat kraftigt bland svenska hästbesättningar de senaste åren, något som tycks bero på utebliven diagnostik och således utebliven behandling av infekterade individer. I dagsläget finns inga tillgängliga studier som visat hur frilevande larver av S. vulgaris beter sig på betet. Studier av små blodmaskar, cyathostominae, samt blandade populationer av blodmaskar har studerats. Det har då antagits att de båda arterna av blodmaskar uppträder på liknande vis gällande överlevnad samt övervintring på betet. Infektiösa larvstadier av cyathostominae kontaminerar beten genom att migrera från träckhögen ut i den omgivande vegetationen, vilket kan påvisas genom att provta gräs från kontaminerade beten. I vilken omfattning S. vulgaris migrerar från träckhögen och hur snabbt smittrycket byggs upp är ännu inte klarlagt. Syftet med den här deskriptiva studien är att få mer kunskap om hur S. vulgaris larver smittar ett bete, samt hur länge smittan finns kvar på betet. Studien har delats upp i tre delstudier. I delstudie 1 undersöktes hur länge larver av S. vulgaris överlever på betet, samt om det är möjligt att detektera betessmitta genom gräsprover. I delstudie 2 studerades smittrycket från S. vulgaris larver och hur långt de migrerar från träckhögar som deponerats på en gräsyta under våren. I delstudie 3 undersöktes kläckning av ägg från S. vulgaris, samt larvers smitttryck och migration till den omgivande vegetationen från träckhögar som deponerats på en gräsyta under hösten. För att besvara frågeställningar i de olika delstudierna togs gräsprov, träckprov och även jordprov (endast i delstudie 1 och 2) vid upprepade tillfällen under sommaren och hösten år 2019. Samtliga prover analyserades sedan för detektion och kvantifiering av L3-larver av S. vulgaris. Resultatet visar att den största smittreservoaren på betet är träckhögarna. Studien visar också att det tar fyra veckor för L3-larver att utvecklas på betet då träckhögar deponeras på en gräsyta på hösten. S. vulgaris kan återfinnas i gräsprov från smittade beten, men parasiten tycks migrera i mycket låg omfattning till den omgivande vegetationen. Att använda gräsprov för att detektera förekomst av S. vulgaris på ett bete är därför ingen bra diagnostisk metod. Då träckhögar fungerar som en reservoar för smitta kan mockning av hagar utgöra ett bra komplement till läkemedel för att reducera smittan från betet. Längre studier med mer frekventa provtagningar är nödvändigt för att fastställa hur S. vulgaris överlever, övervintrar samt migrerar i beteshagen.The large strongyle, Strongylus vulgaris, is a common endoparasite in grazing horses. The parasite has a fecal-oral life cycle, which takes six months to complete. Infected horses spread eggs from S. vulgaris to the pasture with feces. The eggs hatch and develop into larvae the third stage larvae (L3) on pasture and are ingested by grazing horses. The larvae then continue to develop through somatic migration in the horse’s intestines and arteries of the intestine, where they cause lesions in blood vessels, which can be associated with thrombosis, and ischemic lesions of the intestine. The clinical significance of the parasite-induced lesions depend on their magnitude and location. Infected horses can therefor show a broad spectrum of clinical signs including no symptoms to colic and peritonitis. The prevalence of S. vulgaris has increased during the last centuries in Sweden, probably due to the fact that S. vulgaris diagnostics is not always included in the parasite monitoring programme and therefore a risk that low egg shedding horses are left untreated. There are no available studies today explaining the behaviour of free living larvae of S. vulgaris on pasture. In studies of small strongyles, cyathostominae, it has been assumed that small strongyles and S. vulgaris behave in a similar way in terms of survival, migration pattern and overwintering on pasture. Infectious larval stages of cyathostominae contaminate pasture by migrating from feacal patches to the surrounding vegetation. This can be observered by sampling grass from contaminated areas. The extent of how S. vulgaris migrates from the feacal patch and how the infection increases on pasture has not yet been determined. The aim of this descriptive study is to gain more knowledge about how free-living larvae of S. vulgaris infect a pasture and how long the infection remains on contaminated areas. The study has been divided into three minor studies. In study 1, we investigated how long free living stages of S. vulgaris survives on pasture and whether it is possible to detect infection on pasture with grass samples. In the second study, the infection pressure from larvae of S. vulgaris was studied and how and when the larvae migrate from the feacal patch deposited on pasture during the spring. In the third study the hatching of eggs from S. vulgaris was studied, as well as larval infection pressure and migration to surrounding vegetation from feacal patch deposited on pasture during the autumn. To answer the questions, samples from grass, feces and soil were collected repeatedly during the summer and autumn of 2019. All samples were analysed for detection and quantification of third stage larvae of S. vulgaris. The results of this study show that the greatest reservoir on pasture are the feacal patches. The study also shows that S. vulgaris larvae migrate from the feacal pach to the surrounding vegatation to a low extent. Manual removal of feces from pasture is therefore a good alternative to anthelmintic drugs to reduce pasture contamination. Grass samples on pasture needs to be complimented with samples from the feacal patches to detect the presence of S. vulgaris in pasture. These preliminary data need to be further evaluated with longer studies and more frequent sampling to determine how S. vulgaris survives, overwinters and migrate on pasture

  • Strongylus vulgaris and Anoplocephala perfoliata : impacts on the gastrointestinal tract of the horse
    SLU Dept. of Biomedical Sciences and Veterinary Public Health, 2017
    Co-Authors: Ling Julia
    Abstract:

    Strongylus vulgaris (stora blodmasken) och Anoplocephala perfoliata (bandmask) är två av hästens betesburna inälvsparasiter. Infektion med dessa förknippas ofta med ohälsa och gastrointestinala besvär hos hästen. För att minska parasitbördan och undvika resistensutveckling tillämpas idag en selektiv avmaskningsstrategi i Sverige. Det innebär att behandling med anthelmintika endast ska ske vid bekräftad parasitinfektion. Idag analyseras äggförekomst i träckprov för att detektera förekomst av A. perfoliata. men än finns ingen helt tillförlitlig metod för att kvantifiera antalet bandmaskägg. För detektion av S. vulgaris krävs förutom träckprov, en tidskrävande odling av äggen till larvstadium L3, för korrekt diagnos. Gemensamt för de båda parasiterna är att det ännu inte finns någon rapporterad resistens mot anthelmintika. Larvstadier av S. vulgaris migrerar från tarmen till Arteria mesenterica cranialis och dess förgreningar. Obduktionsfynd visar att larvernas vandring skapar en lokal inflammation i blodkärlen, kallad verminös arterit. Skador på kärlens endotel kan ge upphov till trombbildning, vilket har setts orsaka ischemiska skador på hästens tarm. A. perfoliata orsakar problem i övergången mellan ileum och cecum, där vuxna maskar ger upphov till en lokal inflammation. Bandmaskrelaterade skador bekräftas förvärras med infektionens intensitet, vilket ger upphov till olika grader av enterit. Parasitförekomst är vanligt hos betande hästar och kolik är ofta ett multifaktoriellt orsakat tillstånd. Det råder därför delade meningar om eller hur de båda parasiterna ger upphov till kolikbesvär hos hästen. En studie har dock lyckats hitta ett samband mellan ischemisk kolik och infektion med S. vulgaris. Andra forskare har även funnit ett samband mellan spasmodisk kolik och ileumförstoppning vid hög förekomst av A. perfoliata. Det finns brister i dagens diagnostiska metoder då infektion med S. vulgaris eller A. perfoliata ska bekräftas och det blir ett problem då sambandet mellan kolik och parasitinfektion ska studeras. Det faktum att det inte är möjligt att kvantifiera antalet bandmaskägg, samt att det vid identifiering av S. vulgaris inte är möjligt att detektera patogena larvstadier, har gjort att nya analysmetoder har beprövats. Användning av serologiska tester och indirekt ELISA är nyutvecklad diagnostik som än inte används frekvent i praktiken. Vid parasitinfektion sker ett immunologiskt svar i form av IgG(T)-antikroppar hos hästen. Det är idag möjligt att mäta hästens IgG(T)-nivåer vid infektion med både S. vulgaris och A. perfoliata. I ett fåtal studier har forskare lyckats identifiera och kvantifiera tidiga larvstadier av S. vulgaris samt antalet vuxna A. perfoliata med hjälp av indirekt ELISA. Än behöver metoden utvecklas, men den tros vara ett viktigt kliniskt verktyg för att detektera parasitförekomst i framtiden. Syftet med litteraturstudien är att undersöka hur S. vulgaris och A. perfoliata påverkar hästens gastrointestinalkanal och om det finns något samband mellan infektion med respektive parasit och kolik. Litteraturstudien syftar också till att undersöka vilka diagnostiska metoder som finns tillgängliga för att utreda ett eventuellt samband mellan kolik och parasitinfektion.The large strongyle, Strongylus vulgaris, and the tapeworm, Anoplocephala perfoliata, are two common internal helminths in grazing horses. Both S. vulgaris and A. perfoliata are considered pathogenic, due to the injuries they cause in the horse’s intestinal tract. To lower the parasitic burden and to avoid anthelmintic resistance, Sweden has implemented a strategy called selective therapy. This means, that only horses that are confirmed infected with S. vulgaris or A. perfoliata should be treated with anthelmintics. Today, fecal samples are analysed to examine if horses are infected, but the capacity of these analyses are limited. It is not possible to exactly quantify the intensity of an infection with A. perfoliata. To identify S. vulgaris, it requires that a time-consuming larval culture is performed. There are no reports of resistance to anthelmintics in neither S. vulgaris or A. perfoliata. Several parasite-induced lesions have been found during necropsy of horses infected with S. vulgaris and A. perfoliata. Migrating larvae of S. vulgaris cause a verminous endarteritis in A. mesenterica cranialis and its branches. The damage of the blood vessels can cause thrombosis, which can be associated with infarctions and ischemic lesions of the intestine. Adult worms of A. perfoliata attaches to the mucosa around the ileocaecal junction, where they cause lesions and local inflammation. The severity of the lesions caused by A. perfoliata is proportional to parasite infection intensity. Internal parasites are common in grazing horses and colic is often a multifactorial caused condition. Due to these facts, opinions are divided between if and how these two helmints can cause colic. An association between colic caused by nonstrangulation infarctions and S. vulgaris has been shown in one study. Other studies have shown that tapeworm infection is a risk factor for spasmodic colic and ileal impaction colic. The diagnostic methods that are available for detection of S. vulgaris and A. perfoliata are limited, which creates difficulties when examining the association between the internal helminths and colic. Fecal sample analyses that are used today, are not able to quantify the eggs of A. perfoliata or detecting the pathogenic larvae stages of S. vulgaris. According to these facts, new diagnostic tools are under development. An indirect antibody ELISA for diagnosing S. vulgaris and A. perfoliata is under development. The horse’s immune system responds with IgG(T) antibodies towards these parasites and the indirect antibody ELISA makes it possible to measure the antibody levels. Some studies have used these new assays to both quantify the intensity of infection with A. perfoliata and quantify early larvae stages of S.vulgaris. These assays still need development to be used in practice, but it seems to be a diagnostic tool for the future. The aim of this study is to examine how S. vulgaris and A. perfoliata affect the intestinal tract of the horse, and if infection with these gastrointestinal helminths can be associated with colic. The purpose of this study is also to examine available diagnostic tools that can be used to investigate if the helminths can cause colic in horses

  • Strongylus vulgaris och Anoplocephela perfoliata
    2017
    Co-Authors: Ling Julia
    Abstract:

    Strongylus vulgaris (stora blodmasken) och Anoplocephala perfoliata (bandmask) är två av hästens betesburna inälvsparasiter. Infektion med dessa förknippas ofta med ohälsa och gastrointestinala besvär hos hästen. För att minska parasitbördan och undvika resistensutveckling tillämpas idag en selektiv avmaskningsstrategi i Sverige. Det innebär att behandling med anthelmintika endast ska ske vid bekräftad parasitinfektion. Idag analyseras äggförekomst i träckprov för att detektera förekomst av A. perfoliata. men än finns ingen helt tillförlitlig metod för att kvantifiera antalet bandmaskägg. För detektion av S. vulgaris krävs förutom träckprov, en tidskrävande odling av äggen till larvstadium L3, för korrekt diagnos. Gemensamt för de båda parasiterna är att det ännu inte finns någon rapporterad resistens mot anthelmintika. Larvstadier av S. vulgaris migrerar från tarmen till Arteria mesenterica cranialis och dess förgreningar. Obduktionsfynd visar att larvernas vandring skapar en lokal inflammation i blodkärlen, kallad verminös arterit. Skador på kärlens endotel kan ge upphov till trombbildning, vilket har setts orsaka ischemiska skador på hästens tarm. A. perfoliata orsakar problem i övergången mellan ileum och cecum, där vuxna maskar ger upphov till en lokal inflammation. Bandmaskrelaterade skador bekräftas förvärras med infektionens intensitet, vilket ger upphov till olika grader av enterit. Parasitförekomst är vanligt hos betande hästar och kolik är ofta ett multifaktoriellt orsakat tillstånd. Det råder därför delade meningar om eller hur de båda parasiterna ger upphov till kolikbesvär hos hästen. En studie har dock lyckats hitta ett samband mellan ischemisk kolik och infektion med S. vulgaris. Andra forskare har även funnit ett samband mellan spasmodisk kolik och ileumförstoppning vid hög förekomst av A. perfoliata. Det finns brister i dagens diagnostiska metoder då infektion med S. vulgaris eller A. perfoliata ska bekräftas och det blir ett problem då sambandet mellan kolik och parasitinfektion ska studeras. Det faktum att det inte är möjligt att kvantifiera antalet bandmaskägg, samt att det vid identifiering av S. vulgaris inte är möjligt att detektera patogena larvstadier, har gjort att nya analysmetoder har beprövats. Användning av serologiska tester och indirekt ELISA är nyutvecklad diagnostik som än inte används frekvent i praktiken. Vid parasitinfektion sker ett immunologiskt svar i form av IgG(T)-antikroppar hos hästen. Det är idag möjligt att mäta hästens IgG(T)-nivåer vid infektion med både S. vulgaris och A. perfoliata. I ett fåtal studier har forskare lyckats identifiera och kvantifiera tidiga larvstadier av S. vulgaris samt antalet vuxna A. perfoliata med hjälp av indirekt ELISA. Än behöver metoden utvecklas, men den tros vara ett viktigt kliniskt verktyg för att detektera parasitförekomst i framtiden. Syftet med litteraturstudien är att undersöka hur S. vulgaris och A. perfoliata påverkar hästens gastrointestinalkanal och om det finns något samband mellan infektion med respektive parasit och kolik. Litteraturstudien syftar också till att undersöka vilka diagnostiska metoder som finns tillgängliga för att utreda ett eventuellt samband mellan kolik och parasitinfektion.The large strongyle, Strongylus vulgaris, and the tapeworm, Anoplocephala perfoliata, are two common internal helminths in grazing horses. Both S. vulgaris and A. perfoliata are considered pathogenic, due to the injuries they cause in the horse’s intestinal tract. To lower the parasitic burden and to avoid anthelmintic resistance, Sweden has implemented a strategy called selective therapy. This means, that only horses that are confirmed infected with S. vulgaris or A. perfoliata should be treated with anthelmintics. Today, fecal samples are analysed to examine if horses are infected, but the capacity of these analyses are limited. It is not possible to exactly quantify the intensity of an infection with A. perfoliata. To identify S. vulgaris, it requires that a time-consuming larval culture is performed. There are no reports of resistance to anthelmintics in neither S. vulgaris or A. perfoliata. Several parasite-induced lesions have been found during necropsy of horses infected with S. vulgaris and A. perfoliata. Migrating larvae of S. vulgaris cause a verminous endarteritis in A. mesenterica cranialis and its branches. The damage of the blood vessels can cause thrombosis, which can be associated with infarctions and ischemic lesions of the intestine. Adult worms of A. perfoliata attaches to the mucosa around the ileocaecal junction, where they cause lesions and local inflammation. The severity of the lesions caused by A. perfoliata is proportional to parasite infection intensity. Internal parasites are common in grazing horses and colic is often a multifactorial caused condition. Due to these facts, opinions are divided between if and how these two helmints can cause colic. An association between colic caused by nonstrangulation infarctions and S. vulgaris has been shown in one study. Other studies have shown that tapeworm infection is a risk factor for spasmodic colic and ileal impaction colic. The diagnostic methods that are available for detection of S. vulgaris and A. perfoliata are limited, which creates difficulties when examining the association between the internal helminths and colic. Fecal sample analyses that are used today, are not able to quantify the eggs of A. perfoliata or detecting the pathogenic larvae stages of S. vulgaris. According to these facts, new diagnostic tools are under development. An indirect antibody ELISA for diagnosing S. vulgaris and A. perfoliata is under development. The horse’s immune system responds with IgG(T) antibodies towards these parasites and the indirect antibody ELISA makes it possible to measure the antibody levels. Some studies have used these new assays to both quantify the intensity of infection with A. perfoliata and quantify early larvae stages of S.vulgaris. These assays still need development to be used in practice, but it seems to be a diagnostic tool for the future. The aim of this study is to examine how S. vulgaris and A. perfoliata affect the intestinal tract of the horse, and if infection with these gastrointestinal helminths can be associated with colic. The purpose of this study is also to examine available diagnostic tools that can be used to investigate if the helminths can cause colic in horses

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