yst s ▁become ▁inf ect ive ▁and ▁management ▁of ▁the ▁animals ▁living ▁conditions ▁and ▁feed ▁and ▁how ▁easily ▁the ▁animals ▁get ▁inf ected . ▁In ▁general , ▁path ogen ic ▁E imer ia ▁species , ▁including ▁E . ▁zu ern ii , ▁can ▁cause ▁three ▁types ▁of ▁disease ▁in ▁a ▁her d ▁that ▁often ▁manifest ▁as ▁out break s . ▁Winter ▁c occ id ios is / e imer ios is ▁– ▁animals ▁becoming ▁more ▁sus cept ibile ▁to ▁in fe ctions ▁due ▁to ▁cold ▁and ▁crow ding ▁of ▁the ▁animals ▁facil itate ▁the ▁spread ▁( h ous ing ▁of ▁cattle ▁at ▁the ▁end ▁of ▁a ▁past ure ▁season ).. ▁Summer ▁c occ id ios is / e imer ios is ▁– ▁sus cept ible ▁animals ▁ing est ing ▁over w inter ing ▁o oc yst s ▁on ▁past ures ▁on ▁turn - out ▁and ▁increased ▁sp or ulation ▁of ▁new ▁o oc yst s ▁due ▁to ▁increasing ▁temper atures . ▁ ▁Im mun ology ▁Following ▁the ▁initial ▁in fection ▁with ▁an ▁E imer ia ▁species ▁the ▁animal ▁usually ▁is ▁protected ▁by ▁imm unity ▁to ▁that ▁species , ▁and ▁is ▁less ▁likely ▁to ▁develop ▁disease . ▁ ▁The ▁level ▁of ▁imm unity ▁depend ▁on ▁the ▁amount ▁of ▁o oc yst s ▁that ▁inf ected ▁the ▁animal . ▁He avy ▁in fe ctions ▁with ▁E imer ia ▁zu ern ii ▁in ▁cal ves ▁can ▁produce ▁more ▁of ▁the ▁ac ute ▁phase ▁prote ins ▁ha pt og lo bin ▁and ▁Ser um ▁am y lo