Eperythrozoonosis means literally an infection with a parasite upon the erythrocytes. This appears to be a very common condition of swine in Kansas as indicated by the relative ease with which eperythrozoa can be recovered from adult hogs. Clinical evidence of this infection, referred to as acute eperythrozoonosis, occurs only sporadically. The acute condition is also known as icteroanemia, anaplasmosis-like disease, or yellow-belly of swine.