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==Description==

==Description==

Cyathostomins are also known as small strongyles, and are one of the most important gastro-intestinal parasites of the horse. Over 40 species and several genera have been identified. The small, thread-like worms inhabit the caecum and the large colon with their developmental stages confined to the mucosa of the large intestine. Unlike the large strongyles, they do not undergo any extra-intestinal migration during development.  

Cyathostomins are also known as small strongyles, and are one of the most important gastro-intestinal parasites of the horse. Over 40 species and several genera have been identified. The small, thread-like worms inhabit the caecum and the large colon, with their developmental stages confined to the mucosa of the large intestine. Unlike the large strongyles, they do not undergo any extra-intestinal migration during development.  

Both an acute and chronic form of larval cyathostomosis occur in horses. The acute form occurs due to the re-emergence of 'encysted' (hypobiotic) thrid stage larvae from the intestinal wall, and horses with this type of disease are usually affected during late winter or early spring.  

Both an acute and chronic form of larval cyathostomosis occur in horses. The acute form occurs due to the re-emergence of 'encysted' (hypobiotic) thrid stage larvae from the intestinal wall, and horses with this type of disease are usually affected during late winter or early spring.  

The chronic form occurs when ingested third stage larvae develop to the fourth stage without interruption, leading to inflammation and thickening of the intestinal mucosa. Larval emergence may occur throughout the summer and autumn, leading to the clinical signs of associated with a 'wormy' horse. This type of cyathostomosis is more commonly seen in younger horses who have not developed full immunity.

The chronic form occurs when ingested third stage larvae develop to the fourth stage without interruption, leading to inflammation and thickening of the intestinal mucosa. Larval emergence may occur throughout the summer and autumn, leading to the clinical signs of associated with a 'wormy' horse. This type of cyathostomosis is more commonly seen in younger horses who have not yet developed full immunity against the parasite.

==Signalment==

==Signalment==

All horses may be affected but most are less than five years old. Disease commonly occurs in late winter or early spring. A history of an unthrifty or 'poor do-ing' young horse combined with identifcation of larvae in faeces may arouse clinical suspicion of cyathostomosis. Geriatric animals also have an increased susceptibility.  

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-ing' young horse combined with identifcation of larvae in faeces may arouse clinical suspicion of cyathostomosis.  

===Clinical Signs===

===Clinical Signs===

* 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 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==

Large numbers of thread-like larvae in faeces The clinical features of cyathostomosis are relatively non-specific so diagnosis may not be straightforward. Faecal egg counts may not be useful as the disease results from the presence of larvae.  

The clinical features of cyathostomosis are relatively non-specific so 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:

 

 

Affected horses may show the following abnormalities on haematology and biochemistry:

* Hyperglobulinaemia (especially IgG)

* Hyperglobulinaemia (especially IgG)

* Hypoalbuminaemia

* Hypoalbuminaemia

Gross examination of faeces may reveal bright red fourth or fifth stage larvae, and larvae may be found on the rectal sleeve following rectal examination.  Faecal egg counts may be low due to the disease being caused by emerging larvae.

Gross examination of faeces may reveal large numbers of small, thread like larvae. Larvae may also be found on the plastic sleeve following rectal examination.   

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.