Example 1) Visna Maedi virus causes a slow immune complex disease with cellular infiltration of the lungs (or brain and joints) following repeated bouts of replication in macrophages by antigen variants of this lentivirus (cf HIV).

Example 2) Sheep pulmonary adenomatosis virus, (Jaagsieke) causes slow large tumours of the alveolar lining cells with death at 3-4y, common, no diagnostic test apart from the wheel barrow test.

Example 3) Sendai virus of mouse colonies, (parainfluenza virus1) causes chronic lung lesions which interfere with slide reading of carcinogenecity tests. Only use rodents from colonies that are certified free of antibodies to Sendai.