Even the critics of stent use and surgery say a subset of symptomless patients may benefit from the procedures.

WSJ: Are Stroke Drugs Better Than Stents?

While not dangerous, and often symptomless in more healthy patients, in the elderly, weak or immuno-suppressed, MRSA can cause fever and pneumonia.

BBC: NEWS | Health | Hospital infections: Case studies

The new screening will invite younger, symptomless patients to have a similar camera check, a flexible sigmoidoscopy, of the lower part of their large bowel to look for any abnormal growths.

BBC: Bowel-cancer screening pilot to begin in England

In adult sheep, infection is apparently symptomless.

BBC: Schmallenberg virus: First Welsh case in Ceredigion