Pneumococcal disease infections are caused by the bacteria Streptococcus pneumoniae , also known as pneumococcus. Streptococcus pneumoniae is transmitted by droplet spread, by direct oral contact, or indirectly through articles freshly soiled with respiratory discharges. Person to person transmission is common, but illness among casual contacts and health care workers is infrequent and thus antibiotic prophylaxis of contacts is not a routine practice. The immunologic mechanism that allows the disease to occur in a carrier is not clearly understood. Invasive pneumococcal disease most often occurs when a predisposition condition exists, particularly pulmonary disease.
Incidence is highest during winter and spring months.
The ISDH has voluntarily requested information on invasive pneumococcal isolates since 1998. Laboratories and local health department staff have been most cooperative in this effort, with almost 700 cases of invasive disease being reported in 1999. A form specific to Streptococcus pneumoniae has been developed for use by local health departments and others to collect surveillance data on this disease. Later this year, pending approval of the amended Communicable Disease Reporting Rule, reporting of invasive pneumococcal disease and antibiotic sensitivity test results will become mandatory. There are now two different types of vaccine to protect against pneumococcal disease.