Transmission of some species of internal parasites in horse foals born in 2013 in the same pasture on a farm in Central Kentucky

Tolliver, S. C.; Lyons, E. T.; Nielsen, Martin K.; Bellaw, Jennifer L.

doi:10.1515/helmin-2015-0035

Cited by 6 publications

(4 citation statements)

References 17 publications

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“…The included standard necropsies generally made fewer constraints on host enrollment, with some utilizing euthanized cases at veterinary hospitals or carcasses from slaughterhouses with varying ages and treatment histories [3,6]. For the NAm standard necropsies, in particular, most horses were used from university research herds with little to no anthelmintic exposure [39][40][41][42][43][44][45][46][47], and a large number included foals well under six months of age with young, developing infections of low intensity and species richness [40][41][42][43][44]. Likewise, EEur standard necropsies ranged from opportunistic abattoir collection [3] to use of horses experimentally infected with naturally mixed cyathostomin larvae [48].…”

Section: Discussionmentioning

confidence: 99%

Meta-analysis of cyathostomin species-specific prevalence and relative abundance in domestic horses from 1975–2020: emphasis on geographical region and specimen collection method

Bellaw

Nielsen

2020

Parasites Vectors

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Background Cyathostomins infect virtually all horses, and concomitant infections with 10 or more species per horse is standard. Species-specific knowledge is limited, despite potential species bias in development of disease and anthelmintic resistance. This is the first meta-analysis to examine effects of geographical region and cyathostomin collection method on reported composition of cyathostomin communities. Methods Thirty-seven articles published in English in 1975 or later, in which adults of individual species were systematically enumerated, were included. Seven regions; North America, South America, eastern Europe, western Europe, northern Europe, southern Africa, and Oceania, and three cyathostomin collection methods; (i) standard necropsy recovery from the large intestine, (ii) critical test collection from post-treatment feces and necropsy, and (iii) diagnostic deworming recovery solely from post-treatment feces, were considered. Generalized mixed linear models analyzed the effects of region and collection method on species-specific prevalence and relative abundance. Species richness was analyzed by mixed linear models. Results Definitively, the most prevalent and relatively abundant species were Cylicocyclus nassatus (prevalence = 93%, relative abundance = 20%), Cylicostephanus (Cys.) longibursatus (93%, 20%), and Cyathostomum catinatum (90%, 16%). A bias toward horses with high infection intensities and cyathostomin collection from feces resulted in North American critical tests and eastern European diagnostic deworming overestimating the species-specific prevalence and underestimating the relative abundance of rare/uncommon species compared to respective intra-regional standard necropsies. North American critical tests underestimated species richness due partially to identification key errors. Inter-regional standard necropsy comparisons yielded some species-specific regional differences, including a significantly higher Cys. longibursatus prevalence and relative abundance in North America (92%, 33%) than in eastern Europe (51%, 7%) (P > 0.0001). Localization of critical tests to North America and diagnostic deworming to Eastern Europe precluded expansive ‘region by collection method’ interaction analyses. Conclusion We provide substantial data to inform study design, e.g. effect and study size, for cyathostomin research and highlight necessity for method standardization and raw data accessibility for optimal post-factum comparisons.

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Section: Discussionmentioning

confidence: 99%

Meta-analysis of cyathostomin species-specific prevalence and relative abundance in domestic horses from 1975–2020: emphasis on geographical region and specimen collection method

Bellaw

Nielsen

2020

Parasites Vectors

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“…; Tolliver et al . ). If large strongyles were still prevalent within the herd, foals of this age group could acquire larval infections, but the magnitude should be minimal and unlikely to cause clinical manifestations.…”

Section: Two To 6 Monthsmentioning

confidence: 97%

“…As mentioned previously, few cyathostomin larvae undergo arrested development during a horse's first grazing season (Tolliver et al . ), so mucosal populations may be in a constant state of progressive development. Accordingly, there is little justification for administering larvicidal treatments to horses aged less than one year.…”

Section: Weaning To One Yearmentioning

confidence: 99%

Control of helminth parasites in juvenile horses

Reinemeyer

Nielsen

2016

Equine Veterinary Education

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Summary Parasite control in juvenile horses remains a substantial challenge for veterinary practitioners and their clients. This age group is at risk for various types of parasitic disease because their worm burdens tend to be larger and more diverse than in mature horses. This contrast is largely attributable to marked differences in relative levels of acquired immunity. Frequent, perennial anthelmintic treatment is not a sustainable approach for parasite control in this age group, but the simple, surveillance‐based parasite control strategies recommended for mature horses are not appropriate for juveniles either. Maneuvering through the early years of a horse's life requires up‐to‐date knowledge about biology and epidemiology of the parasite species in play as well as local evidence regarding the anthelmintic resistance status of each herd. This article provides an overview of the most important helminth parasites to target in a control programme for juvenile horses, and highlights how the target species change as horses age. Young foals (<2 months) are exposed to Strongyloides westeri and Parascaris spp., whereas the primary target parasite in foals between age 2 months and weaning is Parascaris spp. Beyond weaning, the focus shifts away from ascarids, and the targets instead are strongyles and tapeworms. Gasterophilus spp. and Oxyuris equi are also discussed.

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“…The proportion of foals infected with S. westeri on breeding farms in central Kentucky has ranged from 90%, 6%, 1.5%, to recently, 30%, reportedly mirroring the introduction and reduction of ivermectin use, although 33% was also reported in an anthelmintic‐free research herd (Lyons et al, 1993; Lyons & Tolliver, 2004, 2014a, 2015; Todd et al, 1949; Tolliver et al, 2015). The proportion of infected foals and the prevalence of positive S. westeri FEC tests within the foal population on breeding farms in Ireland is unknown.…”

Section: Introductionmentioning

confidence: 99%

Strongyloides westeri infection on a Thoroughbred breeding farm in Ireland (2014–2019): Prevalence, risk factors and peripartum ivermectin

Kirtland

McAloon

Walshe

et al. 2022

Equine Veterinary Education

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Background:The mean proportion of Strongyloides westeri (S. westeri) infected foals on Thoroughbred breeding farms in central Kentucky has been reported as 30%. The prevalence of S. westeri in Ireland and the effect of peripartum ivermectin treatment of the dam are unknown. Objectives:The objectives of the study were to determine the proportion of foals infected and the prevalence of positive S. westeri faecal egg count (FEC) tests within defined age groups on a Thoroughbred breeding farm in Ireland between 2014 and 2019 inclusive and, furthermore, to identify risk factors for infection and the effect of peripartum ivermectin treatment. We hypothesised no significant difference in S. westeri infection in progeny <365 days of age, where the dam received peripartum ivermectin treatment between 30 days pre-and 7 days post-foaling, versus no treatment. Study design: Retrospective observational cohort.Methods: Farm records of 1420 FECs for 459 foals were reviewed. Positive test prevalence and proportion of foals infected were determined using days between birth and each FEC result, up to 365 days. A mixed effects logistic regression model was constructed to examine the association between date of sample collection, year, age at sampling, peripartum dam ivermectin treatment and S. westeri patent infection in progeny <365 days of age.Results: Test prevalence and proportion of foals infected increased from 0.09 to 0.43 and 0.17 to 0.52, respectively. The risk of positive S. westeri infection was linearly and positively associated with day of the year (OR = 1.75; 95% CI: 1.14, 2.7; p = 0.01) and negatively associated with age (OR = 0.37; 95% CI: 0.23, 0.59; p = <0.001). Peripartum ivermectin treatment was associated with reduced S. westeri infection in progeny <365 days of age (OR = 0.24; 95% CI: 0.07, 0.79; p = 0.02). Main limitations:Faecal egg counts performed by trained lay personnel. Dynamic population. Conclusions:Increasing prevalence of S. westeri infection may reflect cumulative environmental contamination.

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Transmission of some species of internal parasites in horse foals born in 2013 in the same pasture on a farm in Central Kentucky

Cited by 6 publications

References 17 publications

Meta-analysis of cyathostomin species-specific prevalence and relative abundance in domestic horses from 1975–2020: emphasis on geographical region and specimen collection method

Meta-analysis of cyathostomin species-specific prevalence and relative abundance in domestic horses from 1975–2020: emphasis on geographical region and specimen collection method

Control of helminth parasites in juvenile horses

Strongyloides westeri infection on a Thoroughbred breeding farm in Ireland (2014–2019): Prevalence, risk factors and peripartum ivermectin

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