[Characteristics of infectious diseases in the elderly].
Infectious diseases represent the third cause of mortality in patients aged over 65. Age-related immune deficiency and underlying diseases frequently favour infections. The symptoms are often fickle and misleading, delay diagnosis and worsen the prognosis. THE PRINCIPLE INFECTIONS: Broncho-pulmonary and urinary infections predominate in this context. More rare but severe complications specifically related to age are also possible, notably meningitis, tuberculosis, herpes zoster and septicemia in the elderly. Influenza and anti-pneumococcal vaccines have demonstrated their efficacy in limiting the broncho-pulmonary infections in these patients.