West Nile fever (WNF) is zoonotic natural foci arboviral infection with transmissible mechanism of transmission. The human first case was detected in Africa in 1937. WNF is an interdisciplinary problem with planetary distribution. Severe clinical forms of the disease with a high proportion of fatal endings, the absence of effective drugs for therapy, very expensive introduction of monitoring system, and measures for protection of population determine a high medical and social importance of this infection. On the recommendation of WHO experts, WNF is attributed to infectious diseases that make a high threat and are monitored at international level.

WNF is endemic in many countries in Africa, Central Asia, Caucasus, Russia, Central and North America, Australia and most European countries (Spain, Portugal, France, Italy, Turkey, Hungary, Slovakia, Romania, Moldova and others) are involved. The first human case of WNF in Ukraine was registered in 2006, since then sporadic cases occur annually. Today the existence of natural foci of WNF had been confirmed in the North-Western Black Sea area (Odessa, Mykolaiv, Kherson regions and Crimea). The enzootic area found in other regions of Ukraine, including Sumy, Poltava, Lviv, Ivano-Frankovsk, Transcarpathian, Khmelnitsky, Vinnitsa, Cherkassy, Dnipropetrovsk, Zaporizhye and Donetsk oblasts, all of which represent different landscape and geographic areas of our country.

WNF belongs to the genus Flavivirus of the family Flaviviridae. The main hosts of the virus are wild birds of water complex and one’s seasonal migrations ensure ones intercontinental distribution. Additional hosts can be synanthropic birds and mammals. The spread of the virus is due to transmissible mechanism and factors of transmission are mosquitoes Culex, Aedes, Anopheles, which are able to inoculate the virus from saliva approximately 2 weeks after bite of infected birds or animals. In Europe, the main type of mosquitoes that transmit WNF for people are Culex pipiens. The most popular ones varieties associated with adaptive features to the environment are ornithophily (rural) Culex pipiens pipiens and antropophily (city) Culex pipiens f. molestus.

Susceptibility of human for WNF is high. Clinically the disease manifests with different variants: asymptomatic, flu-like (feverish) and neuroinvasive (meningitis, encephalitis, acute flaccid paralysis) forms. A high prevalence of antibodies to WNF in population of hyperendemic areas indicates about asymptomatic infection.

Risk groups of infection WNF virus are often residents of the rural and suburban areas, especially those who live near water objects, employees of livestock and poultry farms, hunters, foresters, tourists, military personnel who is in the field conditions or at conducting of hostilities on the territory of natural foci. The group of medical risk should include recipients (blood products, organs for transplantation, etc.), laboratory staff, newborns of infected mothers, researchers who are studying the WNF problem. In hyperendemic regions often young children and people older than 50 years are ill, and the disease manifests with severe clinical forms in these patients.

So natural foci arboviral infection, including WNF remain an urgent problem in the world and for Ukraine in particular. Therefore, it is needed the optimization and implementation an effective system of prevention, countermeasures and antiepizootic measures against this biological threats in our country.

Keywords: West Nile fever, epidemiology, prevalence

Full text: PDF (Ukr) 799K

1. 1. Vynograd N, Yurchenko O, Dubinа D. Arboviral infections of Northwestern Black Sea. Infectious diseases. 2013;3:5-9.
2. 2. Vynograd N. Principles and types of epidemiological surveillance of extremely dangerous infections, taking into account national priorities of Ukraine. In:Materials of the seminar «Actual problems of prevention of extremely dangerous infections and Biosafety». Simferopol; 2008:19-21.
3. 3. Vynograd N, Vasylyshyn Z, Kozak L. Special epidemiology. Kyiv: «Medicine»; 2014. 343.
4. 4. Vynograd N, Kozak L, Vasylyshyn Z. Epidemiological aspects of natural foci zooantroponses in the West Ukraine. Journal infectology: Materials of the Second Congress Euro-Azyal society of infectious diseases. 2012;4(3):33.
5. 5. Mohilevska Z, Mohilevskyy L, Yurchenko О, Zakusylo V, Rusev I. Epidemiological significance of mosquito in spreading pathogens of arboviral infections in urban areas of southern Ukraine. Infectious diseases. 2008;4:22–25.
6. 6. Stegniy B, Masha A, Yevtushenko A, Mishchenko О, Sumakova N. Blood-sucking arthropods - vectors of pathogens of transmissible infections. Veterinary Medicine. 2012;96:198-199.
7. 7. Kozko V, Bondarenko A, Mohylynets A, Bondar О. West Nile Fever. Actual Infectology. 2013;1(1):129-133.
8. 8. Domashenko A, Belomerya T, Daragan G. West Nile fever - new disease in Donetsk region. Clinical infectology and parazytology. 2012;3-4(03):10-12.
9. 9. Lvov D. Guide to virusology: Viruses and viral infections of human and animals. Moscow: "Publishing" Medical information Agency"; 2013. 1200.
10. 10. Markovich I, Hrynevych O. Analysis on the epidemic situation in Ukraine of zooantroponoses during 2011-2012. Ukraine. Health of the nation; 2013;2(26):125-129.
11. 11. The IHR 2005 / WHO, 2005. - who.int/ru.
12. 12.Shopenskaya T, Fedorov M, Karan L, Pohodyna V, Levin L, Malenko G. New variant of West Nile virus and its potentcial epizootic and epidemiological importance. Epidemiology and infectious diseases. 2008;5:38-44.
13. 13. Pakhomov O, Gorban V, Voronov N. Ecological and biological characteristics of existence Aedes Vexans (Diptera, Culicidae) in the conditions of steppe Dnieper area. Dnepropetrovsk: 2005; 203)
14. 14. Pokrovsky V, Uhleva S, Shabalina S. Comparative characteristics of transmissible fevers on the territory Astrahan regions (on the data of clinical and epidemiological research). Therapeutic Archive. 2011;11:55-59.
15. 15. Yurchenko O. Transmissible viral infections of Northwest Black Sea Region: Thesis… sciences. degree candidate of Biol. sciences: special. 03.00.06 «Virology». Kyiv, 2013. 24.
16. 16. Smithburn K, Hughes T, Burke A, Paul J. A neurotropic virus isolated from the blood of a native of Uganda. American J. Trop. Med. 1940;20(4):471-492.
17. 17. Arnold C. West Nile virus bites back. Lancet. 2012;11(12):1023-1024. doi.org/10.1016/S1474-4422(12)70278-8
18. 18. Calistri P, Giovannini A, Hubalek Z, Ionescu A, Monaco F, Savini G. Epidemiology of West Nile in Europe and the Mediterranean Basin. The Open Virology Journal. 2010;4:29-37. doi.org/10.2174/1874357901004010029
19. 19. Hubalek Z, Halouzka J. West Nile fever – a reemerging mosquito- borne viral disease in Europe. Emerg. Infect. Dis. 1999;5(5):643-650.
20. 20. McIntosh B, Jupp P, Santos I. Dos. Epidemics of West Nile and Sindbis viruses in South Africa with Culex (Culex) univittatus Theobald as vector. S. Afr. J. Science. 1976;72:295-300.
21. 21. Tsai T, Popovici F, Cernescu C, Campbell G, Nedelcu N. West Nile encephalitis epidemic in southeastern Romania. Lancet. 1998;352(9130):767-771. doi.org/10.1016/S0140-6736(98)03538-7
22. 22. Vinogradova E, Shaikevich E. Morphometric, physiological and molecular characteristics of underground populations of the urban mosquito Culex pipiens f. Molestus Forskal (Diptera: Culicidae) from several areas of Russia. Eur. Mosq. Bull. 2007;23:25-30.
23. 23. Vynograd N. Natural foci diseases as a stable biological threat. Archivum Immunologiae et Therapiae Experimentalis. 2014;62(6):445-447. doi.org/10.1007/s00005-014-0316-8
24. 24. Colpitts T, Conway M, Montgomery R. West Nile Virus: biology, transmission, and human infection. Clin. Microbiol. Rev. 2012;25(4):635-648.
25. 25. Zou S, Foster G, Dodd R, Petersen L, Stramer S. West Nile fever characteristics among viremic persons identified through blood donor screening. J. Infect. Dis. 2010;202(9):1354-01361.