Barber's pole worm

(Haemonchus placei, H. contortus)

Haemonchus placei is an extremely pathogenic parasite of cattle in summer rainfall and tropical regions of Australia, although clinical disease is rarely a problem in winter rainfall areas.

H. contortus is the species of barber’s pole worm that infects sheep and goats.

Sheep and goats are more susceptible to the cattle species H. placei than cattle are to the sheep species, H. contortus.

Barber’s pole worms are blood sucking parasites. They can be fatal for young cattle, and cows in their first lactation, especially if other blood sucking parasites such as hookworm (Bunostomum phlebotomum) or liver fluke are also present. Even moderate infections of barber’s pole worm can have a marked effect on the milk production of cows.

The adult female worms are relatively long (20 to 30 mm) and clearly visible. They have the characteristic ‘barber’s pole’ appearance due to the pink (blood-filled) intestinal tract of the worm twisted around the paler reproductive tract; whereas the males are smaller (around 15 mm) and pale pink (Figure 1). Females are prolific egg layers, laying up to 10 000 eggs per day, and as such, much higher worm egg counts are usually seen with these worms than with other worms.

Adults can become arrested or inhibited inside cattle for varying periods and resume development when there is a return to favourable external environmental conditions.

Resistance to drench treatments has been reported.

Further ecological information on worms and their control:

  • Roundworm life cycle and life stages
  • Barber’s pole worms have a typical roundworm life cycle. Inhibition of the early fourth (L4) stage in the mucosa (membrane lining) of the abomasal (fourth stomach) wall can occur for about 3-6 months.
  • The pre-patent period is 26-28 days after infection. The pre-patent period for H. contortus in sheep is 19-21 days.
  • Climate factors contributing to paddock contamination with worms
  • Pasture management to reduce exposure to worms
  • Cost of roundworms

Location in cattle

4th stomach or abomasum.

Signs

Anaemia (due to the worm’s blood sucking activities) and the effects of anaemia such as lethargy and collapse, failure to gain weight, bottle-jaw (sub-mandibular oedema), constipation, and deaths are commonly seen. In acute outbreaks stock become critically anaemic whereas in chronic disease decreased food intake, failure to gain weight and anaemia are commonly observed.

Signs of worms

Diagnosis

The only accurate way to confirm worm infections in cattle up to the age of 12 months, and before productivity losses have occurred, is to conduct a worm egg count (WEC). As small intestinal worm eggs are typically ‘strongyle type’, also request a larval culture or DNA test. The results allow you to determine the need for a drench or management action.

Worm egg counting does not always correlate well with the number of adult worms present for cattle over 9 months of age. For this age group observation of physical signs such as body condition scoring and monitoring target growth weights are good additional indicators to diagnose worm infections.

If visual signs of worms are present in cattle then significant production loss has already occurred. Also, these signs can occur with other parasites and diseases.

Treatment

There are many options to treat for this worm and your choice of drench and management options will depend on:

  • The current size of the burden of this worm.
  • What other worms are also present and in what proportion?
  • Which drenches are effective on your property and the length of protection you are seeking?
  • The likely worm-risk over the next few months.
  • The likely level of worm contamination on your pastures.
  • The class of stock affected and their susceptibility to worms.
  • The last drench group/s you used on this (and other) groups of cattle.
  • The time until these cattle are sold/slaughtered and the withholding period and export slaughter interval of drenches you might use.
  • If these cattle are producing milk for human consumption.

Your decision can be assisted by using the how to decide which animals to treat section and the WormBoss cattle products search guide for your region, a simple tool that considers some of the points above. It is also important to consider cattle management options, as simply removing the affected mob to a less wormy pasture will reduce the re-infection risk.

You can also review the chemical pages on this site to find out specific information about drenches, including their drench active, drench group, how they are administered, which worms they treat, resistance status, safety information and how they work.

The negative impact of this worm can also be reduced through using one of the integrated annual worm control programs that have been specifically developed for different regions across Australia.

Figure 1. Barber’s pole worm showing classic red striping. Image courtesy of Deb Maxwell


 

Figure 2. Barber’s pole worm head showing the lancet which it uses to burrow in and attach to the fourth stomach. Image courtesy of J.A. vanWyk, Faculty of Veterinary Science, University of Pretoria and Onderstepoort Veterinary Institute, South Africa

Figure 3. Adult barber's pole worm, Haemonchus contortis, on a finger to indicate size. Image credit Vethamzah Wikimedia commons

Figure 4. Infective third-stage barber's pole worm larvae suspended in a dew drop on grass. Image courtesy of the National Centre for Veterinary Parasitology, ncvetp.org