Abstract:
Theileria species (sable) causes significant mortalities in roan (Hippotragus equinus), and to a lesser extent, sable antelope (Hippotragus niger) yearly. Treatment of the condition and an ‘infect and treat’ vaccination method using a tick-derived stabilate both rely on the availability of buparvaquone, a naphthoquinone with anti-theilerial activity. As buparvaquone is a controlled drug which is not commercially available in South Africa, a viable commercial alternative prevention or treatment method is necessary to control this disease. This study explores the effectiveness of an alternative vaccination method using Theileria sp. (sable) infected in vitro cultured leukoblasts. A Theileria sp. (sable) containing cell line was initiated from lymph node biopsy material of an infected roan antelope and the parasite was successfully propagated in vitro. Attenuation is believed to have been achieved by 16 cycles of passage. Real time PCR suggests that the parasite was successfully transmitted via subcutaneous inoculation with this cell line to two naïve roan antelope. These two inoculated animals remained clinically unaffected by challenge with a tick stabilate used in the ‘infect and treat’ vaccination method. In contrast, the two unvaccinated control animals became clinically ill and required buparvaquone treatment after challenge. This pilot study provides enough evidence to encourage further investigation in the use of Theileria sp. (sable) infected cells as a potential vaccine. A field study involving more animals which are challenged by natural infection after inoculation is the proposed next step.
