The invention provides an immunogenic polypeptide having the amino acid sequenceM A K S M L S G I V F A G L V A A A A A - S S A N S A A N V S V L E S G P A V Q E - V P A R T V T A R L A K P L L L L S A L - A A T L A A A F L V L Q C F N I I S S N - N Q Q T S V R R L A A G G A C G D E E D - A D E G T S Q Q A S R R R R K P D T P A - A D K Y D F V G G T P V S V T E P N V D - E V L I Q I R N K Q I F L K N P W T G Q - E E Q V L V L E R Q S E E P I L I V A R - T R Q T L E G Y L G S Q A L A Q D G K T - A K E E K V E G G K T H R R Y K V K S S - D P G Y G F P Y T T V L D G V P V G T D - E D G Y V V E V L M K T G P H G G V D M - M T S T A S Q G K F C G V L M D D G K G - N L V D G Q G R K I T A V I G M L T Q P - D T E F R S G P G D D E D D E (SEQ ID NO:1) and fragments thereof,which polypeptides are capable of inducing an immune response against Eimeria parasites, and the DNA encoding such polypeptides, as well as recombinant vectors and recombinant viruses containing the said DNA or fragments thereof and transformed microorganisms containing such vectors and viruses and coccidiosis vaccines comprising such polypeptides.