But it's part of the machismo of the game that a common cold or illness that would keep a normal person out of work shouldn't cause a player to miss a game.

WSJ: The Yanks Need Some Chicken Soup

Schizophrenia is the most common serious mental illness.

BBC: 'Older fathers' link to schizophrenia

The condition is a common form of mental illness, affecting up to 1% of adults worldwide.

BBC: Gene 'has key schizophrenia role'

Mental illness is common.

CNN: Mental illness

The figures also show the most common reason given for absence was illness, not including medical or dental appointments.

BBC: Millions of school days lost to family holidays

Among children aged between one and 14, by far the most common causes of death were cancer, congenital illness and road accidents.

BBC: Adventure playground

Having similar DNA to humans, gorillas are highly susceptible to illness, and even catching a common cold could wipe out an entire group.

BBC: Gorillas in the mix in Uganda

Mental illness has become so broadly defined and so common that it has become meaningless just as, some years earlier, counter-cultural rebellion became so common that it ceased to constitute rebellion at all.

ECONOMIST: The last outsider

There is evidence that some common antibiotics might not work and some experts believe antibiotics could make the illness worse.

BBC: Q&A: E. coli outbreak

"Yes, there are possibilities of acquiring illnesses on airplanes, if you're sitting next to, or close to, somebody who has an illness that may be transmitted through the respiratory route, such as measles or the common cold, " Kozarsky says.

CNN: Business travelers exposed to health risks