GTP-Cyclohydrolase and development in Teladorsagia circumcincta and Dictyocaulus viviparus (Nematoda: Strongylida)

► Mean cat-4 transcript levels highest in larval stages of two nematode species. ► Mean cat-4 transcript levels unchanged in hypobiotic and non-hypobiotic larvae. ► Gene differences occur within and between individual worms. ► The most stable reference genes for qPCR in T. circumcincta are ef-1α & β-tubulin.