Experimental infection of non-immunosuppressed and immunosuppressed goats reveals differential pathogenesis of Babesia aktasi n. sp.

Authors: OZUBEK, SEZAYI - University Of Firat; ULUCESME, MEHMET - University Of Firat; Bastos, Reginaldo; ALZAN, HEBA - Washington State University; LAUGHERY, JACOB - Washington State University; Suarez, Carlos; AKTAS, MUNIR - University Of Firat

Submitted to: Frontiers in Cellular and Infection Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/18/2023
Publication Date: 11/2/2023
Citation: Ozubek, S., Ulucesme, M.C., Bastos, R.G., Alzan, H.F., Laughery, J.M., Suarez, C.E., Aktas, M. 2023. Experimental infection of non-immunosuppressed and immunosuppressed goats reveals differential pathogenesis of Babesia aktasi n. sp. Frontiers in Cellular and Infection Microbiology. 13. Article 1277956. https://doi.org/10.3389/fcimb.2023.1277956.
DOI: https://doi.org/10.3389/fcimb.2023.1277956

Interpretive Summary: Babesiosis is a tick-borne disease caused by Babesia parasites that affects vertebrates globally. Acute disease is characterized by fever, anemia, prostration, and death. Recent advancements in molecular parasitology have identified a new Babesia species, named Babesia aktasi n. sp., which is highly prevalent in goats in the Turkiye's Mediterranean region. The objective of this study was to investigate the mechanism of disease caused by B. aktasi n. sp. in immunosuppressed and healthy goats. After infection, immunosuppressed animals showed high parasitemia, severe anemia, and loss of appetite upon infection, and five out of seven had to be humanly euthanized due to the severity of acute disease. In contrast, healthy goats developed low B. aktasi parasitemia and mild signs of acute disease. Blood analysis showed elevated levels of liver enzymes and decrease of glucose and total protein values in infected immunosuppressed goats, but not in infected healthy animals. In conclusion, this study provides valuable insights into the mechanism of disease of the newly identified B. aktasi n. sp. and serves as a foundation for future research to develop effective prevention and control strategies against babesiosis in small ruminants.

Technical Abstract: Babesiosis, an acute and persistent tick-borne disease caused by protozoans called Babesia, affects vertebrates globally, resulting in symptoms such as high fever, anemia, jaundice, and even death. Advancements in molecular parasitology revealed new Babesia species/genotypes affecting sheep and goats, including Babesia aktasi n. sp. which is highly prevalent in goats from Turkiye's Mediterranean region. The objective of this study was to investigate the pathogenesis of B. aktasi n. sp. infection in immunosuppressed (n=7) and healthy (n=6) goats. These animals were experimentally infected with fresh, B. aktasi n. sp. infected blood, and their clinical symptoms, hematological and serum biochemical parameters were monitored throughout the infection. In the immunosuppressed group, the presence of parasites in the blood was detected by microscopic examination between 4 and 6 days after infection, accompanied by fever and increasing parasitemia. Goats that did not survive acute disease exhibited severe clinical signs, such as anemia, hemoglobinuria, and loss of appetite. However, the goats that survived showed milder clinical signs. In the healthy group, piroplasm forms of B. aktasi n. sp. were observed in the blood within 2-5 days after inoculation, but with low (0.01-0.2%) parasitemia. Although these goats showed clinical findings like loss of appetite, typical signs of babesiosis were absent except for increased body temperature. Hematological analysis revealed significant decreases in the levels of red blood cells, leukocytes and platelets values post-infection in immunosuppressed but not in healthy goats. In addition, serum biochemical analysis showed elevated transaminase live enzymes levels and decreased glucose and total protein values in the immunosuppressed group post-infection. In conclusion, this study provides valuable insights into the pathogenicity of the parasite and will serve as a foundation for future research aimed at developing effective prevention and control strategies against babesiosis in small ruminants.