Health Professionals

Clinical Updates

13 August 2012

West Nile virus (human): Greece

The first human cases of West Nile Virus (WNV) in Greece for many decades were reported in 2010: cases were again reported in 14 prefectures of Greece during the transmission season of 2011 (July to November) [1, 2]. On 7 July, 2012, the Hellenic Centre for Disease Control and Prevention reported the first case of WNV in Greece in a resident of a southern suburb of Athens (Attica), who had onset of symptoms in late June. The case heralded an early start to the 2012 transmission season. Although cases had been reported in the previous year from the prefecture of Attica, this was the first case in Athens [3]. As of 3 August there were 46 laboratory confirmed cases of WNV, including three deaths from seven prefectures of Greece; Attica (in particular from the south suburbs of Athens), Evia, Imathia,Thessaloniki, and from Ahaia, the island of Samos and Xanthi which are a new areas of WNV circulation in the country [1].

 

West Nile virus

WNV is caused by a flavivirus; the primary hosts are birds and horses and the virus is transmitted by Culex sp. mosquitoes. WNV is established in several European and surrounding countries [3]. A map of reported cases in the European Union and neighbouring countries in 2012 is available from the European Centre for Disease Prevention and Control.

The majority of WNV infections (around 80%) are asymptomatic. Less than 20% will experience a mild, self-limited illness with fever, headache, myalgias, and rash. Less than 1% of those infected will develop a more severe neurological syndrome of meningitis and/or encephalitis.

Advice for travellers

The risk of contracting WNV throughout Europe is generally considered to be low [4]  Those of advanced age and underlying medical conditions are at highest risk of developing severe neurological disease following WNV infection [5].

Individuals should take mosquito bite avoidance measures during the transmission season (June to October) when visiting risk areas. There are no vaccines that prevent WNV in humans.

Physicians who see travellers with a characteristic febrile illness, who have returned from WNV endemic areas, including Greece, should be alert to the possibility of WNV infection. Relevant samples for testing together with a full clinical and travel history should be submitted to the Health Protection Agency Rare and Imported Pathogens Laboratory

References

1. Hellenic Centre for Disease Control and Prevention. Ministry of Health. Weekly Epidemiological Report 10 August, 2012. [Accessed 13 August, 2012]. Available at: http://goo.gl/21EPk

2.Institut de Veille Sanitaire. EpiSouth Weekly Epi Bulletin No.225;4-10 July, 2012. [Accessed 13 August, 2012]. Available at: http://www.episouthnetwork.org/sites/default/files/bulletin_

file/eweb_225_12_07_12.pdf

3. European Centre for Disease Prevention and Control. Rapid Risk Assessment. Epidemiological Situation of West Nile Virus in European Union. Update, 13 July, 2012. [Accessed 13 August, 2012]. Available at: http://www.ecdc.europa.eu/en/publications/Publications/1207-TER-Rapid-risk-assessment-West-Nile-virus.pdf

4. Health Protection Agency. West Nile Virus, general information. [Accessed 13 August, 2012] Available at: http://www.hpa.org.uk/Topics/InfectiousDiseases/InfectionsAZ/

WestNileVirus/GeneralInformation/wnile01WestNileVirus

GeneralInformation/#WNV_21

5. European Centre for Disease Prevention and Control. West Nile Fever: Factsheet for Health Professionals. [Accessed 13 August, 2012]. Available at: http://ecdc.europa.eu/en/healthtopics/west_nile_fever/basic

_facts/

Links

European Centre for Disease Prevention and Control. West Nile Fever factsheet

Health Protection Agency: West Nile virus - Advice for Health Professionals

Health Protection Agency Rare and Imported Pathogens Laboratory

Health Protection Agency: West Nile Virus

NaTHNaC Health Information Sheet: West Nile virus

NaTHNaC Health Information Sheet: Insect bite avoidance