The small strongyles also called cyathostomins are among the most important intestinal nematodes of horses (Lyons et al.
Clinically infection with small strongyles can cause mild disease symptoms such as weight loss loss of appetite poor hair coat intermittent diarrhoea lethargy deterioration of condition peripheral edema and disordered intestinal motility (McCraw and Slocombe 1976; Love and Duncan 1992; Love et al.
Internal phase of large strongyles larval development encompasses a somatic migration whereas those of small strongyles burrow into the glands in the caecum and colon and become encysted with no further migration.
Small strongyles larvae invade the lining of the cecum and ventral colon where they grow within fibrous cysts in the mucosa or submucosa and can reside as long as 2.5 years (Reinemeyer 2009).
Pathogenesis: Naturally infected horses usually carry a mixed load of large and small strongyles in the intestine (Owend and Slocombe 1985).
The encysted larvae of small strongyles can emerge synchronously from intestinal wall leading to the clinical disease called larval cyathostominosis' which is associated with clinical signs of oedema diarrhoea pyrexia weight loss colic and can be fatal in up to 50% of cases (Gasser et al 2004).
Small strongyles of genus Trichonema (Cyathostomum) were identified in 47.86% of samples.
Use of broad spectrum anthelmintics like benzimidazoles and macrocyclic lactones has resulted in drastic reduction in worm populations of large strongyles (Konigova et al., 2002, Love, 2003) and now small strongyles are more frequently encountered in horse populations (Boxell et al., 2004).
Comparison of in vitro methods and feccal egg count reduction test for the detection of benzimidazole resistance in small strongyles of horses.