1. Assessment of Draxxin® (tulathromycin) as an inhibitor of in vitro growth of Babesia bovis, Babesia bigemina and Theileria equi.
- Author
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Silva, Marta G., Villarino, Nicolas F., Knowles, Donald P., and Suarez, Carlos E.
- Abstract
Babesia bovis, Babesia bigemina and Theileria equi are worldwide tick-borne hemoprotozoan that cause diseases characterized by fever, anemia, weight loss and abortion. A common feature of these diseases are transition from acute to chronic phases, in which parasites may persist in the host for life, and becoming a reservoir for tick transmission. The live-attenuated vaccines for B. bovis and B. bigemina are not available for worldwide use due to legal restrictions and other concerns such as potential erythrocyte antigen and pathogen contamination, and a vaccine for T. equi is not available. The use of chemotherapeutics is essential to treat and control these diseases, but several studies have shown the development of drug-resistance by these parasites, and safe and effective alternative drugs are needed. Tulathromycin, a macrolide antibiotic, has proven to be effective against a vast range of bacteria and Plasmodium yoelli , a Babesia and Theileria related intra-erythrocytic apicomplexan. Draxxin ® (tulathromycin) is currently licensed to treat infections that cause respiratory diseases in cattle in several countries. In this study, the activity of Draxxin ® was tested in vitro on cultured B. bovis, B. bigemina and T. equi . Addition of the drug to in vitro cultures resulted in cessation of parasite replication of the three species tested, B. bovis, B. bigemina and T. equi , with estimated IC 50 of 16.7 ± 0.6 nM; 6.2 ± 0.2 nM and 2.4 ± 0.1 nM, respectively, at 72 h. Furthermore, neither parasites nor parasite DNA were detectable in cultures treated with IC 100 , suggesting Draxxin ® is a highly effective anti- Babesia / Theileria drug. Importantly, the IC 50 calculated for Draxxin ® for the Babesia/Theileria parasites tested is lower that the IC 50 calculated for some drugs currently in use to control these parasites. Collectively, the data strongly support in vivo testing of Draxxin ® for the treatment of bovine babesiosis and equine piroplasmosis. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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