Babesias are pathogenic parasites belonging to the Protista kingdom. They cause a disease called babesiosis in vertebrate animals. In humans, this disease can occur as zoonosis. The genus Babesia includes over thirty species. Approx. ten of them are considered to be pathogenic.

Babesia canis and Babesia gibsoni cause babesiosis of dogs. It is a disease that attacks animals all over the world. Babesia protozoans are transmitted by ticks. The disease has most often a violent course, untreated leads to the death of the animal. Parasites attack and destroy erythrocytes, what leads to anemia. Considerable damage to the internal organs, especially the kidneys and the liver is commonly reported. In addition, severe circulatory system disorders, as well as jaundice may occure. Symptoms of the disease include: apathy, lack of appetite, lymphadenopathy, high fever, vomiting, diarrhea, urinary problems, hematuria, respiratory and circulatory failure, nervous system disorders.

Babesia divergens causes European hemoglobinuria in cattle. The disease occures in northern Europe. The incubation period is about a week. Symptoms of the disease are similar to those of babesiosis in dogs.