ingest the L3 infective larvae. The infective larvae pass through the first three stomach chambers to reach the abomasum. There, the L3 shed their cuticles and burrow into the internal layer of the abomasum, where they develop into L4, usually within 48 hours, or preadult larvae. The L4 larvae then molt and develop into the L5 adult form. The male and female adults mate and live in the abomasum, where they feed on blood. Genetics The H. contortus draft genome was published in 2013. Further work to complete the reference genome is underway at the Wellcome Trust Sanger Institute in collaboration with the University of Calgary, the University of Glasgow, and the Moredun Research Institute. Developing genetic and genomic resources for this parasite will facilitate the identification of the genetic changes conferring anthelmintic resistance and may help design new drugs or vaccines to combat disease and improve animal health. Pathogenicity Clinical signs are largely due to blood loss. Sudden death may be the only observation in acute infection, while other common clinical signs include pallor, anemia, oedema, ill thrift, lethargy, and depression. The accumulation of fluid in the submandibular tissue, a phenomenon commonly called "bottle jaw", may be seen. Growth and production are significantly reduced. Prevention and treatment Prophylactic anthelmintic treatment necessary to prevent infection in endemic regions, but wherever possible, a reduction on reliance on chemical treatment is warranted given the rapid rise of anthelmintic resistance. A commercial vaccine known as Barbervax in Australia or Wirevax in South Africa has become available in recent years. This works mainly by reducing egg output and hence pasture contamination. The vaccine contains proteins from the lining of the intestines of the Barber's Pole worm. The animal produces antibodies against the protein which circulate in the blood. When the Barber's pole worm drinks the blood the antibodies attach to its stomach lining, preventing digestion and starving the animal. Following this, the worm produces fewer eggs and eventually dies off. Targeted selective treatment methods such as the FAMACHA method may be valuable in reducing the number of dosing intervals, thus reducing the percentage of surviving parasites that are resistant to anthelmintics. Faecal egg counts are used to track parasite infestation levels, individual animals' susceptibility, and anthelmintic effectiveness. Other management strategies include selective breeding for more parasite-resistant sheep or goats (e.g. by culling the most susceptible animals or by introducing parasite-resistant breeds such as Gulf