Primary Prophylaxis: Indications. 1  Prophylaxis should be administered to all HIV-infected patients with a CD4 count of <200 cells/ÂµL, a history of an AIDS-defining illness, or a history of oral thrush. PCP prophylaxis also is indicated for patients with CD4 counts of >200 cells/ÂµL in the presence of a CD4 percentage <14%.
Incubation Period. The incubation period depends on the causative agent. For example the incubation period of meningococcal meningitis is 2-10 days while the incubation for hemophilus meningitis is much shorter ranging from 2-4 days.However the range of incubation for most organisms causing meningitis is 2 days to 2 weeks. Viral meningitis-The most common but less serious form of meningitis. 2  Enteroviruses are the most common viral cause of meningitis in the US. 3  Coxsackie, herpes virus, arbovirus, measles and varicella are other common meningitis causing viruses.
1 The highest incidence of meningitis is between birth and 2 years, with the greatest risk immediately following birth and at 3-8 months of age. 2  Increased exposure to infections and underlying immune system problems present at birth increase an infant's risk of meningitis.