Red mark syndrome (RMS) in farmed rainbow trout: First report of outbreaks in Bosnia and Herzegovina

Red mark syndrome (RMS) is a non-lethal inflammatory skin disorder spreading in farmed adult rainbow trout (Oncorhynchus mykiss) and reported worldwide. The aetiology is still uncertain, but positive correlation was found between Midichloria-like organism and RMS-affected fish. Here, we describe the first cases of RMS in Bosnia and Herzegovina. The outbreaks under study occurred in two intensive farms during the late winter and spring of 2020. Affected fish showed signs of disease ascribable to RMS, confirmed by pathological and molecular examination.