West Nile virus* is mainly transmitted through the bite of infected common mosquitoes.
Mosquitoes become infected by feeding on infected birds, mainly certain species of wild birds. Infected people do not pass the virus on to other mosquitoes or people.
*The virus was named after the West Nile region of Uganda, where it was first identified in 1937.
Complications
Most people infected with the virus do not become ill or develop only mild symptoms.
A small proportion, less than 1% of those infected, develop severe disease affecting the nervous system, mainly encephalitis or meningitis. This can lead to intensive care, long-term neurological complications and, in some cases, death.
Symptoms
Symptoms include sudden fever, severe headache, muscle and joint pain, fatigue and weakness, skin rash, nausea, vomiting or diarrhoea.
Symptoms usually appear two to six days after the mosquito bite, although the incubation period can last up to 14 days.
Who is most at risk?
Those at greater risk of developing severe illness, and who should therefore take particular care to protect themselves from mosquito bites, include:
This year, Greece’s National Public Health Organization (EODY) has recorded widespread circulation of the virus, mainly in Attica, with cases reported in at least 30 of its 66 municipalities. The highest concentration of cases has been recorded in eastern Attica and the northern sector of Athens.
Scientists have linked this year’s increase to weather conditions in recent months. Increased rainfall during winter and spring, high temperatures in recent weeks and low winds have created favourable conditions for mosquito populations.
The numbers
In Greece:
Epidemiologists estimate that the actual number of infections could be 10 times higher and that the transmission season could continue until the end of October.
According to the European Centre for Disease Prevention and Control (ECDC), the virus is circulating in 12 European countries this year.
Prevention
