In vitro cultivation of Babesia canis canis parasites isolated from dogs in Poland

The aim of this study was to perform in vitro cultivation of Babesia canis protozoa isolated from dogs with clinical babesiosis. A primary culture initiated in RPMI-1640 medium supplemented with 40% canine serum supported parasite growth in vitro in 5% carbon dioxide in air atmosphere. Subsequent subcultures into HL-1 medium with 40% dog serum or EMEM with 40% foetal bovine serum also supported parasite propagation. The parasites have been continuously cultured through six passages, although the parasitemias are low, ranging from 0.56% to 0.59%. The partial small subunit ribosomal rRNA gene sequence was identical in blood-derived and culture-derived Babesia. The parasites from 17 cultures were classified as EU622792, and from 13 cultures as EU622793. These data show that an efficient in vitro cultivation of B. canis could serve as a starting point to obtain a protozoan antigen used for immunisation of the dogs against piroplasmosis.