With a little thinking, the packed cell volume (PCV) will answer this question.

Affected cattle are typically treated with tetracycline antibiotics. Also, use of tetracyclines can clear carrier cattle of A. marginale. From 2-5 treatments with LA- 200 (long-acting tetracycline injectable product) given at 7 days intervals will clear the anaplasmosis organism from infected carrier cattle. However, these cattle that are cleared will become susceptible and can actually become ill when re-infected.