This cluster of papers explores emerging animal pathogens and diseases, including retroviruses like Jaagsiekte sheep retrovirus, oomycetes such as Pythium insidiosum, zygomycosis, basidiobolomycosis, and the pathogen Rhinosporidium. It also delves into immunotherapy for these infections and the molecular biology of these pathogens. The papers cover a wide range of topics related to the pathology, diagnosis, treatment, and epidemiology of these emerging animal diseases.