|
Pathogens can enter the body in food or air, through damaged skin, or from contact with infected organisms |
|
They are not, however, the cause of all middle ear infections |
|
So a wide variety of bacteria normally inhabit various parts of the human body |
|
As a result, some of the normal bacterial inhabitants are opportunist pathogens that can cause disease only under certain conditions |
|
Among the harmful species are those that cause, for instance, strepthroaf, dental caries and scarlet fever |