Differentiation of porcine Eimeria spp. by morphologic algorithms.

Oocysts of Eimeria spp. were isolated from feces of naturally infected sows by conventional flotation. Saturated sodium chloride solution was superior to zinc chloride, zinc chloride/sodium chloride or sugar solution to isolate oocysts. Seven species, namely Eimeria scabra, E. polita, E. perminuta, E. debliecki, E. suis, E. porci and E. spinosa, were identified. The dimensions of oocysts (n = 4088) and sporocysts (n = 3594) were measured with an image analysis system; colour and shape of oocysts were estimated and transformed to numerical values. Of the 4088 oocysts approximately 99% were allocated to the correct species by algorithms calculated on the basis of these values. Rough-walled oocysts (E. scabra, E. polita, E. perminuta, E. spinosa) could be distinguished without previous sporulation in most cases (>97%). Smooth-walled oocysts require sporulation for further classification and were accurately allocated to species in at least 93% of cases.