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Babesiosis in a sable antelope (Hippotragus niger Harris, 1838) was first reported in 1930; the parasite was named Babesia irvinesmithi. Recently, specimens from an adult sable that presented with a sudden onset of disease and that subsequently died during immobilization were submitted for molecular characterization. Microscopic examination of thin blood smears revealed the presence of small piroplasms. DNA was extracted from blood samples; the V4 variable region of the 18S rRNA gene was amplified and analyzed using the reverse line blot (RLB) assay. Amplicons did not hybridize with any of the Babesia or Theileria species-specific probes present on the blot and hybridized only with a Babesia or Theileria genus-specific probe, suggesting the presence of a novel species. The full-length 18S rRNA gene sequence was obtained and aligned with published sequences of related genera, and phylogenetic trees were constructed. Sequence similarity analyses indicated that a Babesia species, designated Babesia sp. (sable), was present. The sequence showed its highest similarity to B. orientalis and to an unnamed Babesia species previously detected in bovine samples. The latter was later established to be Babesia occultans. A Babesia sp. (sable)-specific RLB oligonucleotide probe was designed and used to screen 200 South African sable samples, but so far, no other sample has been found to be positive for the presence of Babesia sp. (sable) DNA. In summary, we identified a novel piroplasm parasite from a sable antelope that died from an unknown illness. While the parasite was observed in blood smears, there is no direct evidence that it was the cause of death.

Although large and small piroplasms have been reported from various wild carnivore and ungulate species, relatively few have been named. In the past, mere presence of a piroplasm in a specific host frequently prompted naming of a new species. Descriptions were often inadequate or lacking altogether. Currently, demarcation of species relies heavily on molecular characterisation. Even serological evidence is deemed insufficient. Experimental transmission of Babesia spp. from domestic to wild animals is usually only successful in closely related species, or after splenectomy. There are indications that endemic stability, similar to the situation in livestock, is the general pattern in Babesia sp. infections in wildlife. All lions in Kruger National Park were found to be infected with B. leo, which did not lead to clinical disease manifestation in artificially infected lions. Under stressful conditions, infections could flare up and be fatal, as purportedly happened to the famous lioness "Elsa". Similarly black rhinos, which can harbour Babesia bicornis without ill effects, may develop clinical babesiosis during confinement after capture. Zoo-bred animals, which were not exposed to Babesia spp. at a young age, may be fully susceptible when released into a natural environment where other members of their species occur. This could have major implications for ex situ conservation programmes aimed at bolstering natural wildlife populations.

Outbreaks of autochthonous babesiosis, caused by Babesia canis, occurred in The Netherlands in the spring and autumn of 2004 affecting 23 dogs. Nineteen animals recovered after treatment, whereas four dogs died. Adult Dermacentor reticulatus ticks collected from these dogs indicate that canine babesiosis could become endemic in The Netherlands.

Babesia felis, originally identified in wild cats in the Sudan, was subsequently found to cause clinical disease in domestic cats. Although babesiosis in domestic cats has been reported sporadically from various countries, as a significant disease it appears to be a distinctly South African phenomenon. Apart from an inland focus, feline babesiosis is reported regularly only from coastal regions. The infection is assumed to be tick-borne, but the vector has not been identified. Feline babesiosis tends to be an afebrile, chronic, low-grade disease. The most frequently reported complaints by owners are anorexia and lethargy. The main clinical findings are anemia, depression, and occasionally icterus. Concurrent infections (e.g., Mycoplasma haemofelis, FeLV, FIV) may contribute to the clinical picture. Laboratory findings commonly include regenerative anemia, elevation of alanine transaminase (but not alkaline phosphatase) and total bilirubin concentrations, and a variety of electrolyte disturbances. Secondary immune-mediated hemolytic anemia can be seen occasionally. Drugs effective against other Babesia species give variable and questionable results. The drug of choice is primaquine phosphate, which effects a clinical cure but does not sterilize the infection. Repeated or chronic therapy may be required.