A proposal of standardization for histopathological lesions to characterize fish diseases

The use of histopathology in fish sciences is broadly extended, although it is currently devoid of standardization across the literature. There have been initiatives to standardize every step of the histological evaluation, including description, diagnosis, interpretation, data recording and reporting, and statistical analysis, but, in general, the histopathological systems applied to date present a series of limitations that hamper the reproducibility of the derived data. On top of these limitations, an agreed, organ‐by‐organ list of lesions to be recorded is currently lacking. Therefore, this communication proposes a validated and comprehensive list of features to record in skin, head, eye, nervous system, gastrointestinal tract, gonads, kidney, and other organs of farmed red and Nile tilapias (Oreochromis sp. and Oreochromis niloticus L., respectively), white cachama (Piaractus brachypomus), rainbow trout (Oncorhynchus mykiss) and other species. Once this list is agreed and accepted by fish pathologists and other fish scientists, it could be the cornerstone for the development of well‐established and reproducible histopathological scoring systems. This communication highlights the importance of standardization initiatives in fish histology to produce reliable and high‐quality data.