19 July 2012
Risk of mosquito-borne disease: advice for travellers to Europe and neighbouring countries
Europe has several native mosquito species capable of transmitting disease (e.g. Anopheles and Culex spp). In recent years, other mosquito species (e.g. Aedes spp) have become established in the region. The presence of these species increases the risk of locally acquired mosquito-borne diseases, previously never or rarely seen in Europe, occurring following importation from endemic countries . Travellers may be at risk of these diseases which include:
Chikungunya (CHIKV) is a viral infection of humans and non-human primates transmitted by Aedes spp. mosquitoes. CHIKV is found in tropical and sub-tropical parts of Africa, the islands of the Indian Ocean, and South and South East Asia, and is an emerging disease in parts of Europe .
Between July and September 2007, the first authochthonous (locally acquired) cases of CHIKV occurred in Europe in North Eastern Italy. There were 205 authochthonous cases with one death in this outbreak. The presumed index case was a local resident who developed a febrile illness shortly after returning from India to the region in June 2007 .
In 2010, two authochthonous cases of CHIKV occurred in the Var department, Provence Alpes Azur (PACA) region of France . Between May 2011 and July 2012, there were two imported cases and no autochthonous cases reported in the PACA region [5,6]. Seasonal mosquito surveillance, control and obligatory reporting of suspected and confirmed cases is implemented in the PACA departments of Alpes de Haute Provence, Alpes-Maritimes, Bouches du Rhône, Corse du Sud, Haut Corse and Var .
As of 7 July 2012, no autochthonous cases of CHIKV have been reported in the European Region .
Dengue is a viral infection of humans transmitted by the Aedes spp. mosquito. Dengue symptoms are variable from mild symptoms to severe illness with neurologic and haemorrhagic manifestations.
In September 2010, two cases of autochthonous dengue were reported in Nice (Alpes-Maritimes départment, PACA region) France. These were the first cases to be reported in mainland France . Between 1 May and 13 July 2012, there were nine confirmed cases of imported dengue in PACA region; there have been no further autochthonous cases since 2010 [6, 7]. Seasonal mosquito surveillance, control and obligatory reporting of suspected and confirmed cases is implemented in the PACA departments of Alpes de Haute Provence, Alpes-Maritimes, Bouches du Rhône, Corse du Sud, Haut Corse and Var .
In September 2010, a German tourist developed dengue after returning from the Pelješac peninsula and the island of Korcula in Croatia . In October 2010, a second case of dengue was reported in woman resident in the same area, who had not travelled outside Croatia .
As of 7 July 2012 no autochthonous cases of dengue have been reported in the European Region during this year .
Dirofilarial infection is a parasitic disease in which larval worms (microfilaria) are transmitted from dogs or cats to humans by the bite of an infective mosquito (usually Aedes or Culex spp.). Infection in humans can vary in severity. In Europe, human dirofilaria infections are caused mainly by Dirofilaria repens and are characterised by subcutaneous larval worm nodules near the point of the mosquito bite, or localisation of the parasite to the eye (e.g. orbit, eyelid, subconjunctiva, and vitreous humour). Dirofilaria sp. can infect viscera (e.g. lungs, heart and mesentery.
Dirofilarial infection is an emerging zoonosis in parts of Europe including France, Hungary, Italy and Russia with small numbers of human cases reported annually . Latvia reported two confirmed human cases in August 2011: the first reports of human dirofilarial infection in the country .
West Nile Virus
West Nile Virus (WNV) is a viral illness of humans and birds transmitted by Culex spp mosquitoes. Human infections can be asymptomatic or can vary in severity from mild symptoms to neurological illness including meningitis or encephalitis.
Outbreaks and intermittent cases of human WNV infection have occurred in Europe since the 1950s. Countries reporting cases include Albania, Austria, Belarus, Bosnia, Bulgaria, Croatia, the Czech Republic, France, Greece, Hungary, Italy, Kosovo, Moldova, Montenegro, Portugal, Romania, the Russian Federation, Serbia, Slovakia, Spain and the Ukraine .
The first human cases of WNV in Greece for many decades were reported in 2010: 262 cases and 25 deaths . During 2011, 101 cases of WNV were reported in Greece . As of 19 July 2012, nine cases of WNV are reported from the Attiki region in Greece; cases have not previously been reported from this area .
A map of reported cases in the European Union and neighbouring countries in 2012 is available on the European Centre for Disease Prevention and Control website.
Advice for travellers
Each of these diseases is transmitted to humans by the bite of a mosquito. Practising insect bite avoidance measures will reduce the risk of travellers acquiring a mosquito-borne disease. Travellers should be aware that Aedes spp mosquitoes bite during daylight hours, while Anopheles and Culex spp mosquitoes bite during the evening and night.
Advice for health professionals – the returned traveller
Health professionals should be alert to the possibility of a mosquito-borne disease when consulting with an ill-returned traveller from Europe or neighbouring countries .
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ECDC website: West Nile virus
ECDC website: West Nile fever maps
HPA website: West Nile virus
HPA website: Dengue fever
HPA website: Chikungunya fever