Haemonchus contortus (Barber’s Pole Worm)
About Haemonchus contortus (Barber’s Pole Worm)
Roundworms are common in all grazing sheep flocks. Although adult sheep tend to be less susceptible to roundworms, infections in naive lambs can be associated with production losses. Roundworms can negatively impact on the absorption of nutrients required for growth, The disease, often called parasitic gastroenteritis (PGE) can be associated with diarrhoea, but not always. A variety of factors will affect how disease presents in the sheep, including immune status of the host, overall infection rate and what roundworm types are involved. The predominance of one worm species over another can change the disease presentation. With an increasingly unpredictable climate the mix of worms in individuals and with groups or farms is ever changing. It is important to understand the general biology and risk factors for worm-related disease, but also, how species of worm that can contribute to specific disease presentations.
One of the mixture of roundworms found in the UK is Haemonchus contortus which is a blood-feeding stomach roundworm, also known as the barber’s pole worm. The name “barber pole worm” comes from its twisted red and white appearance that can be seen in the stomach of animals at postmortem.
- Haemonchus contortus is a blood-feeding roundworm that is also known as the “barber’s pole worm” due to its red and white appearance
- The presence of Haemonchus and its status as a problem is driven largely by the prevailing climatic conditions, especially temperature and rainfall
- Haemonchus is becoming more common, even in northern regions, possibly due to climate change. Changing weather throughout the UK may be expected to be more favourable for Haemonchus development and survival on pasture
- Clinical signs are anaemia, ill-thrift with no diarrhoea, and subcutaneous oedema (bottle jaw) and are usually seen in lambs during late summer but can occur in untreated adults which haven’t previously been infected at any time of year
- Sub-clinical infections can cause poor performance and economic losses
- Faecal egg counts, differentiated faecal egg counts, clinical examinations, and postmortems, can help with positive diagnosis
- All classes of broad-spectrum anthelmintic have registered activity against adult H. contortus. In addition, nitroxinil and closantel will kill H. contortus (but not other roundworms) but need to be used with caution (specific diagnosis strongly advised)
- Haemonchus with resistance to anthelmintics is a major problem in the Southern Hemisphere but has also been reported in the UK.
Scientists at Moredun, lead by Dr David Smith, have successfully developed a vaccine for Haemonchus contortus (Barber’s Pole Worm), the most important roundworm parasite of sheep and goats in the world.
Barbervax® was registered for use in Australia in early October 2014 and provides farmers with a revolutionary new tool to combat Barber’s Pole.
The basis for Barbervax® was devised after many years of research at Moredun and commercialised during the last five years through a collaboration with the Albany laboratory of the Department of Agriculture and Food, Western Australia, where it is made by Wormvax Australia, a subsidiary of Moredun.
Barbervax® works against all Barber’s Pole worms including drench resistant ones. It offers a more sustainable form of control, because it is extremely unlikely that vaccine resistant worms will develop. Using Barbervax will reduce the need to use those drenches which are still effective on a particular farm, therefore prolonging their life.
Barbervax® contains tiny amounts of protein purified from the lining of Barber’s Pole intestines. Like all vaccines, it works by stimulating the natural immune response in the animal after injection. The antibodies produced circulate in the sheep’s blood, so that the parasites drink antibodies with their blood meal. These antibodies attach to the lining of the Barber’s Pole intestine, blocking digestion and starving the worm so that it produces far fewer eggs and dies.
Barbervax is available in the following countries:
- Australia: Barbervax can be purchased from several stores in Northern New South Wales and Southern Queensland, where Barbers Pole worm is particularly problematic, but it can be shipped nationwide. Visit Barbervax website.
- UK: Barbervax is currently available in the UK under Veterinary prescription arrangements from Merlin Vets Export Ltd
- South Africa: Barber’s Pole worm is known as Wireworm in South Africa, and as such Barbervax is marketed as Wirevax by Afrivet.