What is a primary use of Droncit in avian medicine?

Droncit, also known as praziquantel, is primarily used in avian medicine to treat tapeworms. This medication is effective against various types of cestodes (tapeworms) that can infect birds and lead to health issues. The mechanism of action involves disrupting the integrity of the parasitic cell membranes, causing the parasites to detach from the host's intestinal wall and be eliminated from the body.

Other options refer to conditions that require different treatments; for instance, lead poisoning is typically managed with chelating agents, while frounce, caused by a protozoan called Trichomonas gallinae, is treated with specific anti-protozoal medications, rather than Droncit. Coccidiosis is an intestinal disease caused by coccidia parasites and is usually treated with medications like sulfonamides or ionophores, not praziquantel. Therefore, the specific efficacy of Droncit against tapeworms makes it the correct answer for its primary use in avian medicine.