Avian Oropharyngeal Trichomonosis: Treatment, Failures and Alternatives, a Systematic Review

Oropharyngeal avian trichomonosis is a potentially lethal parasitic disease that affects several avian orders. This review is focused on the disease treatments since prophylactic treatment is prohibited in most countries and resistant strains are circulating. A systematic review following the PRISMA procedure was conducted and included 60 articles. Successful and non-toxic treatments of avian oropharyngeal trichomonosis started with enheptin, a drug replaced by dimetridazole, metronidazole, ornidazole, carnidazole and ronidazole. Administration in drinking water was the most employed and recommended method, although hierarchy of the avian flocks and palatability of the medicated water can interfere with the treatments. Besides pigeons, treatments with nitroimidazoles were reported in budgerigars, canaries, finches, bald eagles, a cinereous vulture and several falcon species, but resistant strains were reported mainly in domestic pigeons and budgerigars. Novel treatments include new delivery systems proved with traditional drugs and some plant extracts and its main components. Ethanolic extracts from ginger, curry leaf tree and Dennettia tripetala, alkaloid extracts of Peganum harmala and essential oils of Pelargonium roseum and some Lamiaceae were highly active. Pure active compounds from the above extracts displayed good anti-trichomonal activity, although most studies lack a cytotoxicity or in vivo test.