Nematodirus

Nematodirus spp.
Class	Nematoda
Super-family	Trichostrongyloidea

Also known as: Thread-necked worm

Introduction

N. battus is most prominent within the UK, but is also present to a lesser extend in Norway, Sweden, the Netherlands, and Canada. In heavy infections this parasite can be severe, and if left untreated can lead to the death of the carrying host. It is also capable of causing parasitic catarrhal enteritis.

It is a nematode, and is part of the Trichostrongyloidea superfamily.

Predilection site: Small intestine

Hosts

Mainly sheep and goats, but infected cattle are occasionally found.

Nematodirus from ruminant faeces - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona

Identification

A mature adult is around 2cm longer. The female has a prominent spine projecting from the end. The male has a very long slender tail with spicules extended past the bursa.

N. battus eggs are larger than the typical egg of a Trichostrongyle, and have a brownish colouration, with parallel sides.

Life Cycle

The lifecycle of N. battus is different from the common Trichostrongyle lifecycle.

L1-L3 occurs within the egg. The larvae takes several months to develop. Hatching is stimulated by a cold period followed by a night/day temperature of around 10 degrees. The L3 are highly susceptible to changes in climate, so must be ingested soon after moulting to ensure the success of infection.

Pathology is seen when large number of larvae inhabit the small intestine.

N. battus can only hatch from eggs excreted on to pasture in the previous year.

Nematodirosis - Sheep

Nematodirus Learning Resources
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