| dc.description.abstract | The John Cunningham virus (JCV) is an opportunistic virus, which leads to the
development of progressive multifocal leukoencephalopathy (PML). Infection with the
JCV occurs in childhood and the virus remains quiescent in the body, activating during
immunosuppression. Exposure to the virus can be detected by testing for JC virus
specific antibodies in an ELISA test. One of the major unanswered questions of JC virus
epidemiology is whether it is less frequent in Africa than in the West. Our aim was to
determine the JCV seroprevalence and factors associated with its positivity among
Zambian adults presenting to the University Teaching Hospital (UTH) with suspected
meningoencephalitis and to assess the JCV ELISA test as a possible tool for PML risk
stratification.
This was a cross sectional nested study in the TB meningitis in Zambia (TMZ) study
which looked at improving ways of TB diagnosis in patients with meningoencephalitis.
It included adults 18 years and older who presented with suspected meningoencephalitis
and had undergone a lumbar puncture as part of their evaluation. Confirmed PML cases
were also recruited based on clinical features, confirmed by JCV DNA PCR of CSF.
Data was analysed using Epi Info 7. Descriptive statistics were used to determine patient
characteristics and JCV seroprevalence and compared using chi-square tests. Multiple
logistic regression was used to determine the significance of factors associated with JCV
positivity as well as for stratifying PML risk by comparing features of the HIV positive
JCV positive group with confirmed PML cases.
Final analysis for JCV seroprevalence was done in 96 patients and noted to be 46%
(95% CI, 35.62 – 56.31). The JCV seroprevalence in the HIV positive group was
40.82% and in the HIV negative group was 51.06 % but there was no statistical
difference (p-value 0.31). None of the other factors studied had any impact on the JCV
seroprevalence. There was a bimodal distribution of age associated with JCV
seropositivity; with one peak occurring in the 18 to 20 years age group and the second
peak occurring in the 55 to 60 years age group. 14 (3.2%) confirmed PML cases, based
on clinical features and JCV DNA CSF positive, were all JCV seropositive and HIV
positive with advanced immunosuppression (CD4<200/mm3). Memory impairment was
associated with a 6 fold increased likelihood of having PML in advanced HIV disease
with JCV which further, increased to over 20 fold after adjusting for age , gender and
TBM diagnosis. After adjusting for other variables TBM was associated with an 87%
less likelihood of having PML (p-value 0.03). Female gender was associated with
increased risk of having PML (p-value 0.02) and a younger age was protective for PML
(p-value 0.03).
The prevalence of anti-JCV antibodies in patients with suspected CNS infection
(meningoencephalitis) was 46%. Anti- JCV antibody prevalence did not differ
significantly by age, gender, HIV status or CD4 count. Memory impairment in JCV
seropositive, advanced HIV disease patients with meningoencephalitis was the most
important variable associated with having PML. After adjusting for other variables, male
gender, a younger age and diagnosis of TBM were protective of having PML.
Key words: John Cunningham Virus (JCV), Progressive Multifocal Leukoencephalopathy (PML) | en |
