West Nile virus spreads in Greece
West Nile virus appears to have gained a foothold in Greece, spreading to new parts of the country since the first documented outbreak occurred there in 2010, according to data presented at ECCMID 2015.
Researchers from the University of Athens reported on the occurrence and geographic distribution of West Nile virus (WNV) in Greece from 2011 to 2014. Serum and cerebral spinal fluid (CSF) specimens from patients seeking laboratory diagnosis of suspected WNV infection were tested for anti-WNV immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies using enzyme-linked immunosorbent assay (ELISA). Additionally, whole blood and CSF samples were tested for WNV RNA using real-time PCR.
Since 2011, 124 laboratory-confirmed cases of WNV infection were identified and reported to the Hellenic CDC, 70% of which involved severe neurological manifestations and were classified as West Nile neuroinvasive disease (WNND), according to the researchers. The most common risk factors for WNND included hypertension and diabetes. The remaining cases were characterized as West Nile fever. Fifteen deaths have occurred since 2010, all among elderly patients with underlying diseases.
In 2011, most WNV cases were confined to the Eastern Attica prefecture, particularly in the Marathon municipality, where wetlands provided a favorable environment for the reproduction of mosquito vectors. However, during the summer months of 2012 and 2013, cases spread to municipalities of southern and northern Attica. Sporadic cases also were reported from southwestern Greece, including Achaia, Ilia and the Ionian Islands. IgG antibodies were detected in patients from previously unaffected regions, suggesting the previous circulation of WNV in these areas, the researchers noted.
Although the use of larvacides in mosquito-breeding sites in 2014 had successfully reduced the number of emerging vectors and led to a significant reduction of cases, the spread of WNV in newly affected areas indicates that the disease has been established in Greece and cases may continue to occur in the future, according to the researchers.
“Epidemiological surveillance, integrated mosquito management programs and public education on personal protection are crucial to prevent the WNV transmission and control the disease,” they wrote.
Mavrouli M, et al. Abstract P0635. Presented at: European Congress of Clinical Microbiology and Infectious Diseases; April 25-28, 2015; Copenhagen, Denmark.
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