AGD control and disinfection in cleanerfish: Part 2: Challenge trial

Juvenile ballan wrasse, Labrus bergylta were exposed to a Neoparamoeba perurans polyculture either UV irradiated at a low (2mJ cm-2) or high (20mJ cm-2) dose of UV radiation from a medium pressure UV lamp in a beam collimeter. Control fish consisted of un-exposed fish and fish exposed to non-irradiated Neoparamoeba perurans. Over the subsequent 6 weeks of maintainenance, amoebic gill disease (AGD) only developed in the nonirradiated amoeba challenged group with a gross gill score peaking at 3 with 100% prevalence. Similarly, only the non-irradiated amoeba group showed characteristic AGD pathology and was the only group in which Neoparamoeba peruans were detected by PCR. This study indicated that UV irradiation of Neoparamoeba peruans is sufficient to prevent the onset of infection if irradiation exceeds 2 mJ cm-2