UNEXPECTEDLY HIGH NUMBER OF WEST NILE NEUROINVASIVE DISEASES IN BULGARIA IN 2018
Keywords:viral encephalitis, flavivirus, Bulgaria, West Nile virus
West Nile virus (WNV) is an emerging arbovirus in Europe and America which disseminated widely in recent years. This study analysed epidemiological data and laboratory findings of probable and confirmed human WNV cases in Bulgaria in 2018. A total of 15 patients with WNV
infection were detected in 2018, with 2 deaths among them. All patients were diagnosed in August or September. Four patients were from Sofia district, 4 from Burgas, 3 from Plovdiv and 1 from each of the following districts: Shumen, Yambol and Pazardzhik. Laboratory diagnosis for 7 of the patients was based solely on detection of specific antibodies in the serum samples. Eight patients met the criteria for confirmed WNV case. In 6 of them WNV genome was detected by RT-PCR in blood or urine sample and in 3 patients specific IgM antibodies were found in CSF samples which confirmed WNV neuroinvasive infection. The high number of diagnosed human WNV cases in 2018 in Bulgaria is a good sign of increasing recognition of the disease. More efforts are needed in proper transportation of clinical samples undergoing genetic detection of the viral genome. WNV neuroinvasive infection should be suspected and included in the differential diagnosis of viral encephalitis or meningoencephalitis especially in late summer and early autumn.
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