Monday, February 8, 2010
An unfavorable environment or malnutrition decreases resistance to the infection. For instance anthrax, a serious disease in cattle and man, does not affect the normal hen, even when large doses of the organism are injected. If however the hen is exposed to low temperatures, inoculation of anthrax bacilli may produce a fatal disease. Similarly if man is harboring a pathogenic organism, exposure to cold and damp may precipitate health disease, the drunkard’s liability to pneumonia.Infants during their first six months of life are rarely susceptible to many of the common infectious fevers owing to an immunity derived from the mother.
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