Acute CNS infections - Expanding the spectrum of neurological manifestations of hepatitis E virus?

Background: Central nervous system (CNS) infections can be caused by a variety of viruses, but in a significant number of patients no viral or other pathogen can be identified using routine diagnostic work-up. Interestingly, several case reports and series described Hepatitis E virus (HEV) as a potential pathogen. However, systematic studies have not been conducted so far.
Methods: We identified 243 patients from Southwestern Germany with acute CNS infections of unknown cause treated in our clinic between 2008 and 2018, of which serum and/or cerebrospinal fluid (CSF) samples were available. These patients were retrospectively tested for anti-HEV IgM and IgG antibodies. In addition, HEV PCR was performed in the majority of cases including IgM-negative patients with symptom onset <8 days. 263 healthy individuals served as controls.
Results: Evidence of an acute HEV infection was found in four patients (1.7%). Three had recent HEV infection defined as positive anti-HEV IgM and IgG antibodies, one had current HEV infection defined as (additional) detection of HEV RNA in serum. However, anti-HEV IgM and IgG seroprevalence did not differ significantly from controls, though these had considerably lower IgM levels. Interestingly, anti-HEV IgG seroprevalence was unexpectedly high (30.7%) and revealed an age-dependent increase to more than 50% in patients older than 60 years.
Conclusion: This study supports previous findings that HEV could play a role in acute CNS infections. Therefore, we encourage testing for acute HEV infection if no other pathogen can be identified. However, further studies are necessary to prove a causal role.
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