The Open Virology Journal
2010, 4 : 29-37Published online 2010 April 22. DOI: 10.2174/1874357901004010029
Publisher ID: TOVJ-4-29
RESEARCH ARTICLE
Epidemiology of West Nile in Europe and in the Mediterranean Basin
2 Institute for Vector Biology, Brno, Czech Republic
3 Institute of Diagnosis and Animal Health, Bucharest, Romania
* Address correspondence to this author at the Istituto Zooprofilattico Sperimentale dell’Abruzzo e del Molise “G. Caporale”, Teramo, Italy; Tel: +39 0861 332241; Fax: 39 0861 332251; E-mail: p.calistri@izs.it
ABSTRACT
In the last 30 years several cases of West Nile (WN) virus infection were reported in horses and humans in Europe and in the Mediterranean Basin. Most of them were determined by strains of the Lineage 1 included in the European Mediterranean/Kenyan cluster. Strains of this cluster are characterised by a moderate pathogenicity for horses and humans and limited or no pathogenicity for birds. In recent years, however, WN cases determined by strains grouped in the Israeli/American cluster of Lineage 1 or in the lineage 2 have been reported in Hungary and Austria. The role of migrating birds in introducing new viruses to Europe has been often demonstrated. The migratory birds, which may be infected in their African wintering places, carry the virus northward to European sites during spring migrations. In the past, the virus introduction determined occasional cases of WN. In the recent years, new epidemiological scenarios are developing. In few occasions it has been evidenced the capability of WNV strains of overwintering by using local birds and mosquitoes. Species of Culex amongst mosquitoes and magpies (Pica pica), carrion crows (Corvus corone) and rock pigeons (Columba livia) amongst resident birds are the most probable species involved in this hypothetical WND endemic cycle.