Babesia ovis

Authors: OZUBEK, SEZAYI - University Of Firat; AKTAS, MUNIR - University Of Firat; SUAREZ, CARLOS - Retired ARS Employee; Bastos, Reginaldo

Submitted to: Trends in Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/17/2025
Publication Date: 7/9/2025
Citation: Ozubek, S., Aktas, M., Suarez, C.E., Bastos, R.G. 2025. Babesia ovis. Trends in Parasitology. https://doi.org/10.1016/j.pt.2025.06.009.
DOI: https://doi.org/10.1016/j.pt.2025.06.009

Interpretive Summary: Babesia ovis is a tick-borne transmitted blood parasite that causes severe disease in sheep. The parasite is transmitted primarily by Rhipicephalus bursa ticks. B. ovis reproduces asexually in sheep erythrocytes and sexually in the tick midgut. Even at low level of parasites circulating in the blood, B. ovis can cause severe anemia, lysis of red blood cells, jaundice, and high mortality. Disease findings include liver and kidney damage due to alterations in blood vessels. Distribution of the disease is linked to the seasonal activity of R. bursa, with outbreaks peaking from May to July. Transmission of B. ovis occurs only via adult R. bursa ticks, as infected larvae are unable to transmit the parasite. Recent findings confirm that tick transovarial transmission of the parasite plays a critical role in sustaining infection across tick generations. Treatment against B. ovis relies on imidocarb dipropionate, but concerns over drug residues and resistance highlight the need for safer alternatives, including an effective live vaccine.

Technical Abstract: Babesia ovis is a tick-borne intraerythrocytic apicomplexan parasite highly pathogenic to sheep. Transmitted primarily by Rhipicephalus bursa, it has a dixenic life cycle, with asexual stages in sheep erythrocytes and sexual stages in the tick midgut. Even at low parasitemia (0.2%-3%), B. ovis can cause severe anemia, hemoglobinuria, jaundice, and high mortality. Pathological findings include liver and kidney damage due to vascular alterations. The disease's epidemiology is linked to the seasonal activity of R. bursa, with outbreaks peaking from May to July. Transmission of B. ovis occurs only via adult R. bursa ticks, as infected larvae are unable to transmit the parasite. Recent findings confirm that transovarial transmission plays a critical role in sustaining infection across tick generations. Treatment relies on imidocarb dipropionate, but concerns over residues and resistance highlight the need for safer alternatives, including an effective live vaccine.