The benefits of doxycycline result from its ability to remove or reduce the burden of Wolbachia, a rickettsial organism that exists in a symbiotic relationship with heartworms (and other filarids), occupying the reproductive tract and lateral chords of the host parasite (Figure 2). Wolbachia are necessary for the parasite (in this case, Dirofilaria immitis) to develop, thrive, reproduce, and maintain infectivity. https://todaysveterinarypractice.com/parasitology/heartworm-hotline-doxycycline-in-the-management-of-heartworm-disease/
