West Nile virus vaccine still 'years away' as disease spreads in Spain

Antonio's 86-year-old mother was in good health until she was bitten by a mosquito this summer. What started as general malaise slowly got worse and worse.

"She had a severe headache, vomiting, she started getting delirious and had difficulty walking," said her son Antonio Pineda.

She was admitted to the Virgen del Rocío hospital in Seville, Spain but died a few days later. It soon emerged that she had been infected with West Nile virus disease. 

It's not a new illness: the first case was detected in Uganda in 1937, but since then, thousands of cases have been recorded around the world, with more and more recorded every year.

In 80% of cases, the virus barely causes any symptoms and passes as a simple cold.

However, 1% of those infected die and it's not always due to the patient's previous conditions.

"There is a small number of young people with serious infections without previous conditions and we still do not know the reason," said Jordi Figuerola, researcher at the CSIC, Spain's national research council.

The virus has so far been reported as present in 16 European countries. Italy has the highest rate of cases overall, with 331 infected and 13 deaths.

However, the country with the highest death rate is Greece, with 25 people dead and 162 registered cases.

Spain is the third country in Europe most affected by the virus, with 71 confirmed cases and seven deaths. The most recent was just last week in the town of Mairena del Aljarafe in Seville.

It's this southern Spanish province that sees the highest concentration of the virus in humans. In towns like La Puebla del Río, the streets are almost empty at dusk.

Until now, mosquitoes have just been seen in Spain as a mild annoyance that comes with the heat of the summer.

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