Objectives: To determine the role of enteroviruses, Herpesviridae, West Nile virus and Sandfly Toscana virus in central nervous system (CNS) infections in Tunisia.
Methodology: 847 cerebrospinal fluid (CSF) samples, 427 serum samples and 23 stool samples were collected from 1071 patients hospitalized for CNS viral infections from January 2003 through December 2009. All CSF samples were first tested by PCR to detect enteroviruses and Herpesviridae. In specific epidemic contexts in patients negative for these viruses, arbovirus infection was tested by ELISA.
Results: Virological testing was positive in 17.5% of cases. West Nile virus and enteroviruses accounted for 58% of them, enteroviruses 23.5%, Herpesviridae 8.5%, and Toscana virus 10%. West Nile virus infection was observed only in 2003, during an outbreak in coastal regions. Toscana virus circulated regularly throughout the study period. Enteroviruses were responsible for grouped cases of aseptic meningitis in both 2003 and 2005. Arboviruses and enteroviruses were detected mainly in summer and autumn. Herpesviridae were associated with sporadic cases of meningoencephalitis.
Conclusion: This report on viral causes of CNS infections in Tunisia shows that West Nile virus and enteroviruses appear to circulate mainly during epidemics, while the circulation of Toscana virus seems continuous. Negative virus findings may be due, at least in part, to late sampling, inappropriate sample collection and transportation to the virology lab, or failure to test for the right virus. It is essential to promote collaboration between clinicians and biologists to maximize the likelihood of diagnosis.
Keywords: Tunisia; epidemiology; neurological infections; viruses.