There has been recent research into Barber’s Pole Worm indicating that it has undergone significant changes in recent years. BPW has become more tolerant of cooler temperatures and therefore now has a wider geographical spread (see Figure 1 ). The reason for the adaptation to cooler climates is that BPW are now laying eggs all year round. Another change in BPW worm that has been noticed is that it rarely inhibits as an L4, a side effect of effective drenches. Inhibiting allows parasites to exist in regions that have periods of time that do not allow the lifecycle to continue. For example, Barbers Pole is an issue in Sweden of all places as the L4 inhibit over winter and re-emerge in warmer months. Whereas In Australia, it appears that our populations now lay eggs all year, and as mentioned before, this is enabling the worm to adapt to cooler climates.
If we add these population changes of the worm to expected climate changes, Barbers Pole looks set to become more of an issue in areas that historically haven’t had consistent burdens. Intelligence from our faecal egg counting laboratory has indicated that there has never been counts as high as what they are seeing from such diverse areas. So remember, keep up to date with worm testing as the first clinical signs of BPW usually bring death of livestock. Please talk to one of our animal production specialists in store today to develop a drenching program that’s right for you.
Figure 1. The changing distribution of Haemonchus contortus in Australia. (A) Distribution of Haemonchus contortus in 1936. Consistent and sporadic outbreaks of haemonchosis are indicated by the dark and shaded areas, respectively. (B) Predictive distributional modelling of H. contortus based on climatic variables (produced by Dr. Nathan Emery. Triangles indicate the current distribution of H. contortus outbreaks sourced from larval cultures submitted to diagnostic laboratories throughout 2014–2015. There is a higher probability of H. contortus occurring in areas with 700–1200 mm annual rainfall.