Tick-borne encephalitis co-occurring with human herpesvirus 7 replication: a case report and literature review

We report a case of tick-borne encephalitis (TBE) in an immunocompetent 53-year-old female patient who was admitted to our hospital on the 16th day of illness in moderately severe condition with a body temperature up to 38.4 °C and clinical signs of meningoencephalitis. Following lumbar puncture, moderate lymphocytic pleocytosis was detected. A diagnosis of TBE was established, confirmed by epidemiological history (travel to an endemic region, tick bite) and the detection of diagnostic levels of IgM and IgG antibodies in the serum and IgG in the cerebrospinal fluid (CSF) against the TBE virus. Unexpectedly, HHV-7 DNA was detected in the CSF by PCR. After prescribed therapy, the patient’s condition improved, and she was discharged on the 23rd day of her hospital stay. This clinical case illustrates the complexities of diagnostic interpretation when two neurotropic viruses, one of which is HHV-7, coexist during the infectious process. We present scientific literature data regarding the specifics of the infectious process caused by the combined influence of neurotropic viruses, as well as the role of HHV-7 in the development of meningoencephalitis.