Background: The first case of West Nile Virus (WNV) encephalitis in the U.S. was identified in 1999. Over 3,000 cases of WNV have been reported to CDC in 2002. It has been suggested that immunocompromised patients (pts) are at increased risk for WNV encephalitis but only one case in a pt with HIV has been reported. We describe 2 cases of WNV encephalitis among HIV-infected pts.

Methods: Retrospective chart review of pts who had serological testing for WNV requested between May 1 and September 30, 2002.

Results: Nineteen (19) pts had WNV serology performed by the state lab with 5 diagnosed with WNV infection (presence of IgM to WNV by capture ELISA in serum and/or CSF). These 5 pts represent 22% of all pts (n = 23) who tested positive for WNV in Georgia during this period. Their mean age was 54 yrs (range 48–75). Median CSF WBC count was 148 cells/mm³ and median CSF protein was 71 mg/dl. Two (2) of 5 were co-infected with HIV-infected (mean CD4 count 132 cells/μL). One (#1) was a homeless man with a past history of tuberculous meningitis who had been recently arrested and was brought in with nausea, vomiting, headache, and fever followed by altered mental status. He died 18 days after admission; autopsy findings included marked encephalitic changes in the pons and midbrain with microglial nodules, perivascular cuffing by mononuclear cells, and micro- and macro-infarcts. The other HIV co-infected patient (#3) presented with a mild encephalopathy and was discharged after 6 days without complications. On physical exam both had nuchal rigidity without focal neurological findings. Characteristics of the 5 pts and their CSF findings are presented in the table below.

 

Age	Sex	HIV	CD4 cells/uL	West Nile-IgM and IgG	CSF WBC (cells/mm3)	CSF Diff	CSF Prot (mg/dL)	CSF Gluc (mg/dL)
50	M	+	104	IgM+/IgG+	310	44G/39L	91	68
75	F	-	NA	IgM+/ IgG-	67	42G/29L	57	80
48	M	+	161	IgM+/IgG+/-	12	4G/93L	59	44
50	M	-	NA	IgM+/IgG+	35	89L/7M	82	55
48	M	-	NA	IgM+/IgG+/-	219	87G/5L	65	58

 

Discussion: WNV is an emerging infection in the U.S. and should be considered in the differential of acute meningoencephalitis in patients with HIV/AIDS. Little is known about the pathogenesis of WNV among immunosuppressed pts, but cell-mediated immunity may be important for the clearance of viremia and thus HIV-infected pts who acquire WNV may be predisposed to the development of meningoencephalitis.