Testicular immunology
Mumps is a viral disease which causes swelling of the salivary glands and testes. The mumps virus lives in the upper respiratory tract and spreads through direct contact with saliva. Prior to widespread vaccination programs, it was a common childhood disease. Mumps is generally not serious in children, but in adults, where sperm have matured in the testis, it can cause more severe complications, such as infertility.
Social history of viruses
Other, more ancient, viruses have been less of a threat. Herpes viruses first infected the ancestors of modern humans over 80 million years ago. Humans have developed a tolerance to these viruses, and most are infected with at least one species. Records of these milder virus infections are rare, but it is likely that early hominids suffered from colds, influenza and diarrhoea caused by viruses just as humans do today. More recently evolved viruses cause epidemics and pandemics – and it is these that history records. The influenza virus is one that seems to have crossed the species barrier from pigs to ducks and water fowl and hence to humans. It is possible that a fatal plague in the Middle East at the time of the late 18th Dynasty was associated with this transmission at Amarna.