Detection of West Nile virus in human samples: follow-up studies during the 2015 seasonal period

Introduction: West Nile virus, a mosquito-borne viral zoonosis is responsible for human infections in Hungary. Laboratory diagnosis is based on serological tests, however the application of molecular methods has been appreciated. Aim: The aim of the study was to investigate blood, cerebrospinal-fluid and urine samples of acutely ill patients and to follow-up PCR positive cases to ascertain the length of virus excretion. Method: Clinical specimens were examined by indirect-immunofluorescent, haemagglutination-inhibition, two PCR tests and Sanger-sequencing. Virus isolation in case of two patients was successful. Results: A follow-up study could be carried out in case of 5 patients. Viral nucleic acid was detectable in urine even for several weeks after symptom onset and viral RNA was present at higher concentration compared with other samples. Conclusions: PCR analysis of urine could provide useful epidemiological and diagnostic information. Therefore, it is recommended to collect urine samples in order to supplement the serological diagnosis.