Possibilities for occurrence and spread of West Nile Fever virus infection in Bulgaria
| Autor: | Prof. Georgi Georgiev |
|---|---|
| Jazyk: | bulharština |
| Rok vydání: | 2021 |
| Předmět: | |
| DOI: | 10.5281/zenodo.5512043 |
| Popis: | The causative agent of West Nile Disease (WND) is a virus and belongs to the Flaviviridae family of the genus Flavivirus. The WND virus belongs to the antigenic group of Japanese encephalitis, which also includes the Murray Valley encephalitis and Saint Louis encephalitis viruses. The disease has been found in Africa, Europe, the Middle East, Asia, Oceania, and more recently in America. The natural cycle of infection includes birds and mosquitoes, most commonly from the genera Culex spp. and Aedes spp. Many species of wild birds play the role of amplifier hosts, while humans, horses and other mammals are considered as incidental or “dead-end” hosts of the virus. Birds (especially wild migratory birds) are the natural reservoirs in which the WNDV multiplies in large amounts. Due to the high and long-lasting viremia (20-100 days), infected birds are a th3e primary and long-term source of infection for blood-sucking mosquitoes, which infect other birds, as well as humans and horses, through the bite. In recent year the disease has evolved from a new emerging disease in most parts of Southern Europe and the Mediterranean into a seasonal infection and endemic to many countries. The analysis of the scientific facts shows that the climatic-geographical and ecological parameters in Southern and Central Europe are favorable for the development of the competent mosquito vectors of the WND virus by establishing a link between migratory, resident native birds and other vertebrates (incl. agricultural) and man. The conducted serological tests confirm that the WND virus circulates in at least 4 regions of Bulgaria from three districts, including different species of animals and birds. The relatively high percentage of seroprevalence in these regions (43.5% - Durankulak, 39.7% - Shabla, 28.6% - Tutrakan, 30.2% - St. Oryahovo) are probably due to the close coexistence of susceptible animals in proximity to wetlands, visited by large colonies of various species of migratory birds, which can be carriers and a source of WND virus. The discovery of virus-specific antibodies to WND in dead-end equidae suggests that the so-called "bridge" vectors are most likely involved in the virus transmission cycle. This should be taken into account when assessing the risk to people living in rural areas, populated mainly by adult populations (age> 50 years), the group most at risk of developing neuroinvasive disease virus infection. WND viruses from genetic lines 1 and 2 affecting humans and equids have been found to circulate in Europe. This definitely emphasis need for analyzing every current outbreak, which will provide more information on the epidemiological significance and the protection of public health. The competent authorities have to notified the blood transfusion centers to test the blood products appropriately at the blood transfusion centers. BG; docx; EFSAfocalpoint@mzh.government.bg |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|