Two case reports of neuroinvasive West Nile virus infection in the Almaty region, Kazakhstan

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Population screening has confirmed circulation of West Nile virus in the southern region of Kazakhstan (Almaty region).

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We report two cases of meningoencephalitis of unknown etiology occurred in the rural area near Tekeli city, Kazakhstan, in August 2019.

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Retrospective analysis showed high titers of anti-WNV IgG in both patients’ serum specimens obtained on day 9 after the onset of symptoms.

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These are the first reports of West Nile virus infection in Kazakhstan.

Background

West Nile virus (WNV) is a member of the genus Flavivirus, which transmitted to humans mainly by mosquitoes. Recent pilot serosurveillance data from the Almaty region, Kazakhstan, suggest widespread WNV circulation in this area. This report includes two cases of neuroinvasive WNV infection in the same family living in a rural area near Tekeli city, Eskeldinsky district, Almaty region, Kazakhstan. Occurring concurrently and manifesting as WNV infection with febrile illness and symptoms of meningoencephalitis.

Methods

The study performed retrospective analysis of clinical histories and achieved serum samples obtained from patients with febrile and meningoencephalitic syndromes of unknown origin in the Almaty region spanning from April 1 to October 31, 2019. All sera samples obtained from patients with clinically suspected cases of acute WNV infection were retrospectively tested for WNV and tick-borne encephalitis virus by commercial immunoassays. Two cases were selected.

Cases presentation

We report two cases that occurred in August 2019 in a rural area near Tekeli city. Previously healthy 28- and 19-year-old husband and wife with febrile illness and neurological manifestations were hospitalized with the diagnosis of meningoencephalitis of unknown etiology and treated empirically. Retrospective serological analysis showed the presence of high titers of IgG against WNV on day 9 after onset of symptoms in cases.

Conclusions

This is the first report of aseptic meningitis with WNV infection in the background in Kazakhstan. The obtained data suggest circulation of WNV in the Almaty region and emphasize importance of laboratory testing for WNV in suspicious cases occurring in the region.

Unexpected outbreaks of arbovirus infections: lessons learned from the Pacific and tropical America

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