Pathology of Streptococcal meningitis following intravenous intracisternal and natural routes of infection.

The distribution of pathological lesions present in 20 cases of naturally-occurring Streptococcus suis type 2 meningitis and 20 cases of the disease induced experimentally by intravenous or intracisternal inoculation was examined. It was found that the distribution of lesions was similar; mild lesions were present at the choroid plexuses whilst the most dense cellular accumulations were found at sites of cerebrospinal fluid (CSF) efflux, such as arachnoid villi and olfactory nerve sheaths. The distribution of changes was considered to reflect the dynamics of CSF flow rather than indicate the site of entry of the organisms into the CSF compartment.