A commercial vaccine for Barber’s pole worm – further development

Summary

The Barber's Pole worm, Haemonchus contortus, is an important gastrointestinal parasite of sheep and goats in Australia and overseas. Because the parasite prefers warm moist conditions, Haemonchosis is particularly common in the summer rainfall zone especially in North-Eastern NSW and Southern Qld, but the disease can occur sporadically in any State. Haemonchus is usually controlled by anthelmintic drugs, but strains resistant to these chemicals are common and widespread in endemic areas.

lternative methods for control are required. Vaccination could theoretically offer a solution, but no vaccines are currently registered for any gut dwelling worm parasite of any host.

The project to be described is the second part of a three-stage objective where the overall aim is to make an effective Barber's Pole worm vaccine commercially available for Australian sheep producers. This vaccine was developed at the Moredun Research Institute in Scotland following some 20 years work and will be manufactured by one of its subsidiaries, Wormvax Australia, at the Department of Food and Agriculture, Western Australia laboratory in Albany WA . The first part of the overall project was mainly concerned with obtaining a Good Manufacturing Practice licence for the vaccine and with determining vaccine efficacy for lambs in field trials. Most of the trials were done in New England, where Haemonchus is endemic and a serious problem.

The results were successful and culminated in the submission of a dossier to the Australian Pesticide and Veterinary Medicines Authority (APVMA) seeking permission to sell the vaccine as an aid to controlling Barber's Pole in lambs. This first part of the project will be complete when approval of the dossier has been granted. A decision is not expected until August 2014 after which this part of the project will be reported in full. The present project forms the second part of the overall objective and contains results which show that the vaccine affords an epidemiological benefit by reducing pasture contamination with infective worm larvae. In addition, it shows that the vaccine is effective in yearling sheep.

​As soon as possible after the current dossier has been approved, this information will be added to it so that its overall scope is broadened and strengthened. The third part of the project is currently still in the animal trial phase. Its main aim is to determine the ability of the vaccine to confer protection on ewes, both in terms of suppressing their increased susceptibility to infection around lambing and during lactation, an important source of infection for their lambs, but also during the high-risk period in late summer when deaths due to Barber's Pole worm are not uncommon in ewes. If these results are favourable, the data will also be added to the dossier.

herefore if all the trials are successful and approval of the extended dossier is obtained, farmers will be able to use the vaccine in lambs, yearlings and ewes. By these means it is hoped that Australian farmers will have a new tool to combat Barber's Pole worm across their entire flock.