Trypanosoma melophagium from the sheep ked Melophagus ovinus on the island of St Kilda

Researchers have identified Trypanosoma melophagium, a trypanosome parasite transmitted by sheep keds (Melophagus ovinus), in the feral Soay sheep population on St Kilda. Despite being largely eradicated elsewhere in the UK, the sheep ked persists here and was found to harbour T. melophagium in high prevalence, particularly among lambs. The study used PCR analysis of preserved keds and live gut smears, along with in vitro cultivation and morphological examination, to confirm the parasite's identity. Genetic sequencing revealed that T. melophagium is closely related to Trypanosoma theileri, suggesting it represents a specialized lineage adapted to transmission by sheep keds. This finding sheds light on the evolutionary dynamics of trypanosome parasites and their hosts in isolated ecosystems.

GIBSON, W., PILKINGTON, J. G., & PEMBERTON, J. M. (2010). Trypanosoma melophagium from the sheep ked Melophagus ovinus on the island of St Kilda. Parasitology, 137(12), 1799–1804. https://doi.org/10.1017/s0031182010000752