Trypanosomal brain infection
As the causative agent of African Sleeping Sickness, trypanosomes enter the brain during second stage infection, where they deregulate sleep-wake cycle by secretion of prostaglandin D2, causing the typical symptoms like insomnia at night and somnolescence at day. T. brucei was first described within the cerebrospinal fluid (csf) from sleeping sickness patients in 1903, but a final proof how trypanosomes reach the brain has not been presented till today.
Our murine model shows that the parasites first enter the brain via the choroid plexus, whereas they cannot cross the blood-brain barrier. From the plexus stroma, trypanosomes penetrate the epithelial cell layer to reach the ventricular system. Although they cannot develop in csf, they can use the liquor flow to reach the Virchow-Robin space and penetrate the glia limitans. However, we cannot find any trypanosomes within the brain parenchyma, as NMRI mice (and Wistar rats) won’t survive long enough, i.e. more than 30 days.
(partly out of: Brain infection by A. trypanosomes during Sleeping Sickness, NPaBR (2012), 18(2): p49-51)