Assessment of Babesia ovis pathogenicity in goats: Implications for transmission dynamics and host resilience

Authors: OZUBEK, SEZAYI - University Of Firat; ULUCESME, MEHMET - University Of Firat; Suarez, Carlos; Bastos, Reginaldo; AKTAS, MUNIR - University Of Firat

Submitted to: Frontiers in Cellular and Infection Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/15/2024
Publication Date: 11/12/2024
Citation: Ozubek, S., Ulucesme, M.C., Suarez, C.E., Bastos, R.G., Aktas, M. 2024. Assessment of Babesia ovis pathogenicity in goats: Implications for transmission dynamics and host resilience. Frontiers in Cellular and Infection Microbiology. https://doi.org/10.3389/fcimb.2024.1480347.
DOI: https://doi.org/10.3389/fcimb.2024.1480347

Interpretive Summary: The blood parasite Babesia ovis, transmitted by Rhipicephalus bursa ticks, causes significant clinical disease in sheep characterized by severe anemia and high mortality. Despite its importance, the impact of B. ovis on goats remains uncertain. To investigate the pathogenesis of this parasite in goats, we performed experimental infections of spleen-intact and splenectomized goats using infected blood and tick infestation. Notably, no clinical disease was observed in the B. ovis-infected goats. However, B. ovis was transiently detected in two spleen-intact animals using a molecular DNA-detection assay. This finding led us to perform additional experiments to investigate the possible role of goats as reservoirs for B. ovis transmission. Results indicated that chronically B. ovis-infected goats are not significant sources for maintaining the tick-borne transmission cycle of the parasite. Taken together, the findings prove the differential susceptibility of goats to B. ovis infection compared to sheep and their limited role as reservoirs for parasite transmission.

Technical Abstract: Babesia ovis, commonly associated with ovine babesiosis, poses a significant threat to sheep health, often resulting in severe clinical manifestations and high mortality rates. However, the impact of B. ovis on goats has remained uncertain, prompting this study to investigate its pathogenicity in caprine hosts. Experimental infections, through infected blood inoculation and tick infestation, were conducted on spleen-intact (n=5) and splenectomized (n=5) goats. For the experimental infection, fresh B. ovis-infected blood was obtained from a splenectomized sheep. A spleen-intact sheep served as the control for the experimental infection with B. ovis-infected ticks. While sheep displayed severe clinical symptoms and high parasitemia, goats exhibited resilience, showing no significant clinical manifestations or sustained parasitemia. Notably, B. ovis was transiently detected in two spleen-intact goats via nested PCR, prompting further investigation into their role as reservoirs for tick-borne transmission. These goats were then infested with B. ovis-free Rhipicephalus bursa larvae (0.1 gr) and adults (30 females and 30 males) for transstadial and transovarial transmission experiments respectively. Results indicated that chronically B. ovis-infected spleen-intact goats are not significant sources for maintaining the tick-borne transmission cycle of the parasite. These findings highlight the differential susceptibility of goats to B. ovis infection compared to sheep and their limited role as reservoirs for parasite transmission. Understanding the role of goats in B. ovis transmission and their resistance mechanisms can inform effective control measures and reduce economic losses in affected regions. Further research into caprine babesiosis and host immunological responses is essential to fully elucidate the underlying mechanisms of host susceptibility and parasite pathogenesis.