Initial neurological interest in HIV infection was focused on opportunist infections and tumors that affect the CNS. At the time, the CNS was considered to only be indirectly involved in the progression of HIV disease. It is possible that HIV penetrates the CNS in an initial phase of the infection. During this period, the viral load in the peripheral blood is as high as it is in the terminal phase of the illness. Around 5 to 10% of patients present acute viral meningitis, at the time that the virus is acquired or during the seroconversion phase. The penetration of HIV into the CNS through neurons by axonal flow. A more likely possibility is penetration through a hematogenic pathway. The disrupted BBB during HIV infection allows free particles and infected monocytes to penetrate into the CNS. Two types of CNS cells can be infected by HIV, cells derived from monocytes and astrocytes and these cells differ from other infected HIV cells.
Source link: http://emedicine.medscape.com/article/1167008-overview