One of the most unusual symptoms of coronavirus (COVID19) infection is the loss of a sense of smell and taste. Anosmia, the loss of sense of smell, and ageusia, an accompanying diminished sense of taste, have emerged as peculiar telltale signs of Covid-19, the disease caused by the coronavirus, and possible markers of infection. Last Friday (March 20), British ear, nose and throat doctors, citing reports from colleagues around the world, called on adults who lose their senses of smell to isolate themselves for seven days, even if they have no other symptoms, to slow the disease’s spread. The published data is limited, but doctors are concerned enough to raise warnings. Earlier reports from Wuhan, China, where the coronavirus first emerged, had warned that ear, nose and throat specialists as well as eye doctors were infected and dying in large numbers. The British physicians cited reports from other countries indicating that significant numbers of coronavirus patients experienced anosmia, saying that in South Korea, where testing has been widespread, 30 per cent of 2,000 patients who tested positive experienced anosmia as their major presenting symptom (these were mild cases). Moreover, the symptoms, in the absence of allergies or sinusitis, should alert doctors to screen patients for the virus and warrant serious consideration for self isolation and testing of these individuals. In the areas of Italy most heavily affected by the virus, doctors say they have concluded that loss of taste and smell is an indication that a person who otherwise seems healthy is in fact carrying the virus and may be spreading it to others.