The present invention is based upon the identification of a number of antigens derived from species of the genus Teladorsagia, which can be used to raise immune responses in animals - particularly those animals susceptible or predisposed to infection by (or with) one or more Teladorsagia species. The antigens may be exploited to provide compositions and vaccines for raising protective immune responses in animals - the protective immune responses serving to reduce, prevent, treat or eliminate Teladorsagia infections/infestations.
