Cyathostomins

Cyathostomins
Class	Nematoda
Super-family	Strongyloidea
Family	Strongylidae

Also known as: Trichonema spp.

Introduction

Cyathostomins are a group of small strongyles. The majority of cyathostomins are similar in terms of both morphology and behaviour. There are over 50 different species of small equine strongyle, and they are of huge significance throughout the United Kingdom. They commonly cause severe acute diarrhoea and colic - Cyathostomosis.

Identification

They are small worms, generally less than 1.5cm long. They also have a distinctive, small buccal capsule. They also have two rows of leaf crowns, both internal and external.

The species range in colour from white to dark red.

Hosts

Horses and donkeys.

Life Cycle

L1-L3 occurs within the envelope. The L3 then exits the sheath in the small intestine, and then concentrates within the Lieberkuhn's gland. At this stage they are known as EL3, and have two potential options. Firstly, they may either become hypobiotic, remaining dormant for several months to years. This usually occurs Autumn-Winter in temperate climates. Alternatively EL3 may evolve directly into LL3. They will then evolve into L4, at which stage they will emerge from a nodule. After emergence of the cyst, L4 transforms into L5. They then transform into adults in the lumen.

Only two anthelminitics have activity against encysted stages of small redworm, a single dose of moxidectin or a 5-day course of fenbendazole. At 8 weeks post treatment with moxidectin EL3 stages are eliminated. Due to widespread resistance to fenbedazole a faecal egg count reduction test is recommended prior to using it for treatment of the encysted stages.

Highest egg shedding is in the Spring months. The larvae, which represent 90% of the population, are at maximal levels in the autumn.

Cyathostomins Learning Resources
Flashcards Test your knowledge using flashcard type questions	Horse Nematode Flashcards
Literature Search Search for recent publications via CAB Abstract (CABI log in required)	Cyathostomins publications

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