Abstract:
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.
