According to the sources below clindamycin and quinine no longer seem to be first line
Amboss states regarding Babesiosis treatment "Mild to moderate disease: oral atovaquone PLUS oral azithromycin
Severe disease: oral atovaquone PLUS IV azithromycin"
https://next.amboss.com/us/article/P70WNh?q=babesiosis#Y915dad9e85344993ec64abcc84001e4a
Uptodate states regarding mild to moderate disease: "The preferred regimen consists of azithromycin plus atovaquone given orally; clindamycin plus quinine given orally is an alternative option"
For severe disease: "For treatment of severe babesiosis, we favor intravenous (IV) azithromycin plus oral atovaquone; IV clindamycin plus oral quinine is an alternative option"
https://www.uptodate.com/contents/babesiosis-treatment-and-prevention?search=babesiosis&source=search_result&selectedTitle=2%7E64&usage_type=default&display_rank=2
First Aid 2024 (pg. 154) does not differentiate the routes or severity and just states that treatment is "Atovaquone
+ azithromycin"
Source: AMBOSS - https://next.amboss.com/us/article/P70WNh?q=babesiosis#Y915dad9e85344993ec64abcc84001e4a