Immunity to Eimeria brunetti and Eimeria maxima infections in the fowl.

INTRODUCTION It has long been accepted that the resistance developed by fowls to reinfection with the various species of Eimeria which parasitize them is species specific (Tyzzer, Theiler & Jones, 1932; Johnson, 1938). However, careful examination of data obtained in this laboratory suggested that this might not be true for those species which appear to have similar properties. A preliminary report of some cross immunity between E. tenella and E. necatrix has already been made (Rose, 1965) and further work (unpublished) has confirmed this. Because of their marked morphological and biological similarity E. brunetti and E. maxima were selected for further study on cross-immunization between the species of fowl coccidia.