Abstract
Haemonchus contortus is a trichostrongyle nematode parasite of sheep and goats, and worldwide is considered to be the most important parasite of these species. It has a similar lifecycle to other parasitic trichostrongyle gastrointestinal nematodes, but it has a markedly higher fecundity, a preference for higher temperatures and a short pasture development time, which makes it epidemiologically different. Similarly, because of its blood-feeding habit the disease produced is distinct from parasitic gastroenteritis. This article summarises the differences in biology and control of H. contortus to other gastrointestinal nematodes of sheep, and covers specific control measures such as the use of FAMACHA© scoring, use of closantel and nitroxynil, the H. contortus vaccine, the effect of copper oxide wire particles, and the potential for breeding haemonchosis-resistant sheep and other future developments in H. contortus control.
Haemonchus contortus (often called the barber's pole worm) is a haematophagous trichostrongyle nematode parasite of sheep and goats. Unlike other common trichostrongyle parasites, it mainly causes disease through associated blood loss. Worldwide H. contortus is the most important nematode parasite of small ruminants (Waller and Chandrawathani, 2005). As a result of this importance it has served as the model gastrointestinal nematode (GIN) for the genome project (Laing et al, 2013). It is often described as a ‘tropically adapted’ worm, but this description is misleading as it is a major pathogen in countries with very cold winters, such as Canada (Barrere et al, 2013), Sweden (Lindqvist et al, 2001) and Estonia (Tähepõld, personal observation). In the UK it has been found on 50% of sheep farms (Burgess et al, 2012). Within recent years there have been increasing reports of haemonchosis within southern England, and the combination of anthelmintic resistance and changing climate would seem to make this trend likely to continue (Rose et al, 2016).
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