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

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          Highlights

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

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

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

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

          Abstract

          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.

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          Most cited references14

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          Epidemiology and Transmission Dynamics of West Nile Virus Disease

          West Nile virus (WNV) was first detected in the Western Hemisphere in 1999 during an outbreak of encephalitis in New York City. Over the next 5 years, the virus spread across the continental United States as well as north into Canada, and southward into the Caribbean Islands and Latin America (1). This article highlights new information about the epidemiology and transmission dynamics of human WNV disease obtained over the past 5 years of intensified research. Epidemiology WNV is transmitted primarily by the bite of infected mosquitoes that acquire the virus by feeding on infected birds. The intensity of transmission to humans is dependent on abundance and feeding patterns of infected mosquitoes and on local ecology and behavior that influence human exposure to mosquitoes. Although up to 55% of affected populations became infected during epidemics in Africa, more recent outbreaks in Europe and North America have yielded much lower attack rates (1,2). In the area of most intense WNV transmission in Queens, New York, in 1999, ≈2.6% of residents were infected (most of these were asymptomatic infections), and similarly low prevalence of infection has been seen in other areas of the United States (3,4). WNV outbreaks in Europe and the Middle East since 1995 appear to have caused infection in 1,000 potentially WNV-viremic blood donations were identified, and the corresponding blood components were sequestered. Nevertheless, 6 WNV cases due to transfusion were documented in 2003, and at least 1 was documented in 2004, indicating that infectious blood components with low concentrations of WNV may escape current screening tests (19). One instance of possible WNV transmission through dialysis has been reported (20). WNV transmission through organ transplantation was also first described during the 2002 epidemic (15). Chronically immunosuppressed organ transplant patients appear to have an increased risk for severe WNV disease, even after mosquito-acquired infection (16). During 2002, the estimated risk of neuroinvasive WNV disease in solid organ transplant patients in Toronto, Canada, was approximately 40 times greater than in the general population (16). Whether other immunosuppressed or immunocompromised patients are at increased risk for severe WNV disease is uncertain, but severe WNV disease has been described among immunocompromised patients. WNV infection has been occupationally acquired by laboratory workers through percutaneous inoculation and possibly through aerosol exposure (21,22). An outbreak of WNV disease among turkey handlers at a turkey farm raised the possibility of aerosol exposure (17). Dynamics of Transmission: Vectors WNV is transmitted primarily by Culex mosquitoes, but other genera may also be vectors (23). In Europe and Africa, the principal vectors are Cx. pipiens, Cx. univittatus, and Cx. antennatus, and in India, species of the Cx. vishnui complex (6,24). In Australia, Kunjin virus is transmitted primarily by Cx. annulirostris (11). In North America, WNV has been found in 59 different mosquito species with diverse ecology and behavior; however, 40%. Field studies during and after WNV outbreaks in several areas of the United States have confirmed that house sparrows were abundant and frequently infected with WNV, characteristics that would allow them to serve as important amplifying hosts (23,25,37). The importance of birds in dispersing WNV remains speculative. Local movements of resident, nonmigratory birds and long-range travel of migratory birds may both contribute to the spread of WNV (38,39). Although WNV was isolated from rodents in Nigeria and a bat in India, most mammals do not appear to generate viremia levels of sufficient titer to contribute to transmission (24,40–42). Three reptilian and 1 amphibian species (red-ear slider, garter snake, green iguana, and North American bullfrog) were found to be incompetent as amplifying hosts of a North American WNV strain, and no signs of illness developed in these animals (43). Viremia levels of sufficient titer to infect mosquitoes were found after experimental infection of young alligators (Alligator mississippiensis) (44). In Russia, the lake frog (Rana ridibunda) appears to be a competent reservoir (45). Nonmosquitoborne WNV transmission has been observed or strongly suspected among farmed alligators, domestic turkeys in Wisconsin, and domestic geese in Canada (17,46,47). Transmission through close contact has been confirmed in both birds and alligators in laboratory conditions but has yet to be documented in wild vertebrate populations (23,36,44). Control of WNV Transmission Avoiding human exposure to WNV-infected mosquitoes remains the cornerstone for preventing WNV disease. Source reduction, application of larvicides, and targeted spraying of pesticides to kill adult mosquitoes can reduce the abundance of mosquitoes, but demonstrating their impact on the incidence of human WNV disease is challenging because of the difficulty in accounting for all determinants of mosquito abundance and human exposure. One study indicated that clustering of human WNV disease in Chicago varied between mosquito abatement districts, suggesting that mosquito control may have some impact on transmission to humans (14). Persons in WNV-endemic areas should wear insect repellent on skin and clothes when exposed to mosquitoes and avoid being outdoors during dusk to dawn when mosquito vectors of WNV are abundant. Of insect repellents recommended for use on skin, those containing N,N-diethyl-m-toluamide (DEET), picaridin (KBR-3023), or oil of lemon eucalyptus (p-menthane-3,8 diol) provide long-lasting protection (48). Both DEET and permethrin provide effective protection against mosquitoes when applied to clothing. Persons' willingness to use DEET as a repellent appears to be influenced primarily by their level of concern about being bitten by mosquitoes and by their concern that DEET may be harmful to health, despite its good safety record (49). To prevent transmission of WNV through blood transfusion, blood donations in WNV-endemic areas should be screened by using nucleic acid amplification tests. Screening of organ donors for WNV infection has not been universally implemented because of concern about rejecting essential organs after false-positive screening results (50). Pregnant women should avoid exposure to mosquito bites to reduce the risk for intrauterine WNV transmission. Future Directions WNV disease will likely continue to be a public health concern for the foreseeable future; the virus has become established in a broad range of ecologic settings and is transmitted by a relatively large number of mosquito species. WNV will also likely continue to spread into Central and South America, but the public health implications of this spread remain uncertain. Observations thus far in North America indicate that circulation of other flaviviruses, such as dengue, viral mutation, and differing ecologic conditions may yield different clinical manifestations and transmission dynamics. Over the next few years, research efforts might well be focused in several areas. Research into new methods to reduce human exposure to mosquitoes is crucial and can help prevent other mosquitoborne illnesses. This should include development of new methods to reduce mosquito abundance, development of new repellents, and behavioral research to enhance the use of existing effective repellents and other personal protective measures against mosquito bites. A better understanding of the dynamics of nonmosquitoborne transmission is essential to prevent disease among infants of infected mothers and recipients of blood transfusions and transplanted organs. Currently available prevention strategies such as the dissemination of knowledge and products for personal protection from mosquito exposure and the application of existing techniques for reducing mosquito abundance in communities at risk of WNV transmission need to be vigorously implemented. National and international surveillance for WNV transmission will be important to monitor spread of the virus and the effect of control strategies. Finally, further research into the ecologic determinants of WNV transmission, including climatic factors and dynamics of reservoir and vector populations, could help in determining geographic areas of higher risk for WNV disease.
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            West Nile virus.

            West Nile virus (WNV) is responsible for thousands of cases of morbidity and mortality in birds, horses, and humans. Epidemics were localized to Europe, Africa, the Middle East, and parts of Asia, and primarily caused a mild febrile illness in humans. In the late 1990s, the virus became more virulent and spread to North America. In humans, the clinical presentation ranges from asymptomatic, seen frequently, to encephalitis/paralysis and death, seen rarely. There is no FDA (Food and Drug Administration)-licensed vaccine for human use, and the only recommended treatment is supportive care. Often, there is a long recovery period. This article reviews the current literature summarizing the molecular virology, epidemiology, clinical manifestations, pathogenesis, diagnosis, treatment, immunology, and protective measures against WNV and WNV infections in humans. 2010 Elsevier Inc. All rights reserved.
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              West Nile virus.

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                Author and article information

                Contributors
                Journal
                IDCases
                IDCases
                IDCases
                Elsevier
                2214-2509
                15 June 2020
                2020
                15 June 2020
                : 21
                : e00872
                Affiliations
                [a ]Almaty Branch of National Center for Biotechnology, 14g Zhahanger Str., Almaty, 050054, Kazakhstan
                [b ]Tekeli City Hospital, Tekeli, 25 Tauelsizdik Str., Tekeli, 041700, Kazakhstan
                [c ]National Scientific Center of Phthisiopulmonology, Ministry of Health of the Republic of Kazakhstan, 5 Bekhozhina Str., Almaty, 050010, Kazakhstan
                [d ]Al-Farabi Kazakh National University, Department of Epidemiology, Biostatistics and Evidence-based Medicine, 71 Al-Farabi Str., Almaty, 050040, Kazakhstan
                Author notes
                [* ]Corresponding author. am_dmitr@ 123456mail.ru
                Article
                S2214-2509(20)30180-3 e00872
                10.1016/j.idcr.2020.e00872
                7305403
                60aad398-b5a7-41eb-8a2a-8623b98de2c8
                © 2020 The Author(s)

                This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

                History
                : 19 April 2020
                : 11 June 2020
                : 11 June 2020
                Categories
                Article

                csf, cerebrospinalfluid,elisa, enzyme-linkedimmunosorbent assay,esr, erythrocytesedimentation rate,wnv, westnile virus,neuroinvasive west nile virus infection,west nile virus,meningoencephalitic syndrome of unknown origin,almaty region,kazakhstan

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