Pneumococcal disease is an infection caused by a type of bacteria called Streptococcus pneumonia (pneumococcus). Transmission of the pathogen is either person-to-person through respiratory droplets, or by self-inoculation with bacteria previously carried without symptoms in the upper respiratory tract. This bacterium causes the three major clinical syndromes of pneumococcal disease: bacteremia, meningitis, and pneumonia, as well as other lower respiratory tract infections, otitis media, and sinusitis. Mortality from invasive disease (meningitis and bacteremia) is high, particularly among the elderly and the chronically ill.
Pneumococcal pneumonia (lung infection) is the most common serious form of pneumococcal disease. Symptoms include:
Older adults with pneumococcal pneumonia may experience confusion or low alertness, rather than the more common symptoms listed above.
Pneumococcal meningitis is an infection of the covering of the brain and spinal cord. Symptoms include:
Pneumococcus bacteria causes up to half of middle ear infections (otitis media). Symptoms include: