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All horses may be affected but most are less than five years old. Geriatric animals also have an increased susceptibility. Disease commonly occurs in late winter or early spring. A history of an unthrifty or 'poor do-er' young horse combined with identifcation of larvae in faeces may arouse clinical suspicion of cyathostomosis.
All horses may be affected but most are less than five years old. Geriatric animals also have an increased susceptibility. Disease commonly occurs in late winter or early spring. A history of an unthrifty or 'poor do-er' young horse combined with identifcation of larvae in faeces may arouse clinical suspicion of cyathostomosis.
==Clinical Signs==
Acute disease:
Acute disease:
* Increased or decreased appetite
* Increased or decreased appetite
* Recurrent colic
* Recurrent colic
Other clinical features of the disease include ventral oedema due to a protein-losing enteropathy. Adult and larval worms may cause damage to the intestinal mucosa through plug feeding, resulting in ulcer formation.
Other clinical features of the disease include ventral oedema due to a protein-losing enteropathy. Adult and larval worms may cause damage to the intestinal mucosa through plug feeding, resulting in ulcer formation.
==Diagnosis==
==Diagnosis==
The clinical features of cyathostomosis are relatively non-specific and confirming a diagnosis of cyathostomosis may be difficult. Faecal egg counts may not be useful as large numbers of eggs in the faeces do not always indcate a pathological worm burden. Affected horses may show the following abnormalities on haematology and biochemistry:
The clinical features of cyathostomosis are relatively non-specific and confirming a diagnosis of cyathostomosis may be difficult. Faecal egg counts may not be useful as large numbers of eggs in the faeces do not always indcate a pathological worm burden. Affected horses may show the following abnormalities on haematology and biochemistry:
Intestinal biopsy via laparotomy may may reveal a massive eosinophilic infiltration of the mucosa.
Intestinal biopsy via laparotomy may may reveal a massive eosinophilic infiltration of the mucosa.
==Pathology==
==Pathology==
Post mortem examination of the large intestine may reveal larvae in the mucosa, seen as small grey to red mucosal nodules (the characteristic 'pepper-pot' lesion). Mass emergence results in mucosal erosions, ulcers and fibrinous exudate. A catarrhal and haemorrhagic colitis and typhlitis may be seen, with hyperaemia or necrosis of the tissue. In chronic cases, thickening of the intestinal wall may be present. Adult worms (approximately 1.5cm in length) may be seen within the intestinal lumen.
Post mortem examination of the large intestine may reveal larvae in the mucosa, seen as small grey to red mucosal nodules (the characteristic 'pepper-pot' lesion). Mass emergence results in mucosal erosions, ulcers and fibrinous exudate. A catarrhal and haemorrhagic colitis and typhlitis may be seen, with hyperaemia or necrosis of the tissue. In chronic cases, thickening of the intestinal wall may be present. Adult worms (approximately 1.5cm in length) may be seen within the intestinal lumen.
==Treatment==
==Treatment==
Treatment is indicated for horses with faecal egg counts greater than 200 eggs per gram. Cyathostomins are widely resistant to anthelmintics, particularly benzimidazoles. Moxidectin PO is effective against these resistant strains and also against encysted larvae. Refractory cases may benefit from concurrent corticosteroid therapy with prednisolone. Twice-weekly removal of manure from pastures is recommended. Adequate stocking density, grazing management and
Treatment is indicated for horses with faecal egg counts greater than 200 eggs per gram. Cyathostomins are widely resistant to anthelmintics, particularly benzimidazoles. Moxidectin PO is effective against these resistant strains and also against encysted larvae. Refractory cases may benefit from concurrent corticosteroid therapy with prednisolone.
==Prognosis==
==Prognosis==
Approximately 40% of horses affected with acute diarrhoea from larval cyathosomosis will recover if treated appropriately.
Approximately 40% of horses affected with acute diarrhoea from larval cyathosomosis will recover if treated appropriately.
==Prevention==
==Prevention==
Good grazing management such as regular manure removal, harrowing, pasture rotation and grazing horses with ruminants all aid in reducing pasture contamination. Anthemlintic programs should only be used as an adjunct to good hygiene and management practices.
Good grazing management such as regular manure removal, harrowing, pasture rotation and grazing horses with ruminants all aid in reducing pasture contamination. Anthemlintic programs should only be used as an adjunct to good hygiene and management practices.
==References==
* Fox, M and Jacobs, D. (2007) '''Parasitology Study Guide Part 2: Helminths''' ''Royal Veterinary College''
* Fox, M and Jacobs, D. (2007) '''Parasitology Study Guide Part 2: Helminths''' ''Royal Veterinary College''