13. Histopathology can give the initial indication of a viral infection and most infections are described alongside the pathological changes they induce.
14. Electron microscopy used to be the ultimate diagnostic tool for viruses, but polymerase chain reaction has revolutionized our ability to identify infectious agents.
26. Transmission may in some cases be via vectors such as arthropods or leeches, whereas others by direct contact presumably, but most transmission routes are unknown.
27. Due to the lack of commercial value, very little is known about reptilian viruses.