The prevalence and epidemiology of gastrointestinal parasites of horses in Victoria, Australia.

The prevalence and abundance of internal parasites in working horses autopsied in Poland

The small strongyles of horses, also known as cyathostomins, are considered the most prevalent and pathogenic parasites of horses today. The clinical syndrome of larval cyathostominosis which occurs as a result of mass emergence of inhibited stages has a high fatality rate despite the best standard of care given to affected horses. Management of the challenge level of cyathostomins to prevent the syndrome is preferable. Many different management programmes have been tried over the past two decades, with mixed success. Programmes have relied heavily on repeated use of anthelmintic treatments throughout the life of a horse. The widespread incidence of resistance to certain anthelmintics is reducing these options. An understanding of the biology of cyathostomins, risk factors for infection and appropriate strategic use of still effective anthelmintics is essential for the future management of this parasite group. This review highlights the necessity to use currently available anthelmintics that are appropriately suited to the biology of cyathostomins, and to maintain heir efficacy through an appropriate treatment strategy.

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Equine cyathostomins: a review of biology, clinical significance and therapy.

Sustainable equine parasite control: perspectives and research needs.

Few studies have described the combined effect of age, gender, management and control programmes on helminth prevalence and egg shedding in grazing equines. Here, fecal samples collected from 1221 Thoroughbred horses, residing at 22 studs in the UK, were analysed. The distribution of strongyle eggs amongst individuals in relation to age, gender and management practices was investigated. Fecal worm egg counts (FWECs), described as the number of eggs per gramme (epg) of feces, were determined using a modification of the salt flotation method. The FWEC prevalence (mean%) of strongyles, Parascaris equorum, tapeworm spp. and Strongyloides westeri was 56, 9, 4 and 8%, respectively. Strongyle, P. equorum, tapeworm spp. and S. westeri infections were detected on 22 (100%), 11 (50%), 9 (41%) and 8 (36%) of studs, respectively. Within all age and gender categories, strongyle FWECs were highly over-dispersed (arithmetic mean = 95 epg, aggregation parameter k=0·111) amongst horses. Animal age, last anthelmintic type administered and management practices (for example, group rotation on grazing) most strongly influenced strongyle prevalence and level of egg shedding (P < 0·05). Overall, 11% of equines (range: 234-2565 epg) were responsible for excreting 80% of the strongyle eggs detected on FWEC analysis. The results confirm that the judicious application of targeted treatments has potential to control equine strongyle populations by protecting individual horses from high burdens, whilst promoting refugia for anthelmintic susceptible genotypes.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/F1442079BCB46FF527A0EC6DE5073AA8/S0031182012001941a.pdf/div-class-title-helminth-egg-excretion-with-regard-to-age-gender-and-management-practices-on-uk-thoroughbred-studs-div.pdf

Helminth egg excretion with regard to age, gender and management practices on UK Thoroughbred studs.

A postmortem survey of 57 horses in tropical northern Queensland revealed 41 (89%) infected with intestinal strongyles. Thirty-five strongyle species (8 large strongyles and 27 small strongyles [Cyathostominae]) were recorded of which 9 species are reported from Australia for the first time. The 14 most prevalent small strongyles were Cyathostomum catinatum (in 76% of horses), Cyathostomum coronatum (65%), Cyathostomum pateratum (33%), Cyathostomum labiatum (30%), Cylicostephanus calicatus (70%), Cylicostephanus longibursatus (67%), Cylicostephanus goldi (43%), Cylicostephanus minutus (26%), Cylicocylus nassatus (67%), Cylicocyclus leptostomus (41%), Cylicocylus insigne (41%), Cylicocyclus radiatus (33%), Cylicocyclus brevicapsulates (22%), and Poteriostomum imperidentum (24%). The remaining cyathostomes were each found in less than 15% of horses. The 4 most common large strongyles were Triodontophorus serratus (30%), Strongylus vulgaris (28%), Strongylus equinus, and Strongylus edentatus (both 22%). The number of species of small strongyles per horse showed a marked variation (mean 10.3, range 2-21) but bore no relationship to either the total number of strongyles per horse, age, sex, and breed of horse, or season. Total number of strongyles per horse (mean 15,890, range 20-165,000) was less than in recent surveys in Europe and the U.S.A. Most horses had low worm burdens, whereas a very small number were heavily infected. Ninety-seven per cent of the total strongyle counts were small strongyles. Strongylus species contributed just over 1%. Small numbers of large strongyles per horse were usual with T. serratus (mean 570), S. vulgaris (mean 330), and S. equinus (mean 330) the most numerous.(ABSTRACT TRUNCATED AT 250 WORDS)

G. W. Hutchinson

Papers

Prevalence and abundance of equine strongyles (Nematoda: Strongyloidea) in tropical Australia.