Anyone planning to give blood will be asked if they have been in the provinces of Sevilla, Cádiz or Huelva in the last four weeks, due to cases of the so-called Nile Virus being detected in western Andalucía.
A man from Sevilla was found to have caught the infection early in September, and later transpired to be the third in the province.
Horses in Cádiz and Huelva have also been affected.
Health authorities say the ban on giving blood within four weeks of having been in the three provinces is merely a precaution and will stop around the end of November when the mosquitoes which transmit Nile Fever have died off.
Even then, medics say there is no need for alarm – the condition does not involve any symptoms in 80% of cases.
The 20% who do suffer ill effects from the Nile Virus mainly report ‘flu-like symptoms.
Only around 1% have serious complications, like meningitis or meningoencephalitis.
But blood containing the virus, even with a 1% risk of serious problems, cannot be used, and even with the milder ‘flu symptoms in a possible 20%, infected transfusions given to patients with very serious conditions, especially where the immune system is all but lacking, could result in major complications.
As yet, no person-to-person infection has been reported, says Dr Luisa Barea, director-general of the Transfusion Centre in the Greater Madrid region.
Blood bank technicians analyse donations for a long list of conditions, including HIV, Hepatitis B and C, and syphilis.
But when an infection which is not on the list to be tested for is reported, the donor is placed in ‘quarantine’ – or not allowed to give blood – for the full length of the incubation period and a little longer as an extra precaution.
Testing is only then carried out if a high number of patients carrying the condition is detected, or in the areas where the infection is found.
For example, in Huelva, Sevilla and Cádiz, nobody is stopped from giving blood, since health autorities in these provinces are automatically testing for the Nile Virus – but elsewhere in the country, testing is not carried out due to there being no incidence of the condition, meaning anyone who has been in western Andalucía will be asked to come back in four weeks’ time.
“These measures are routine whenever cases of an infection are found in any humans,” explains Dr Barea.
“It doesn’t mean that the virus is going to turn into an epidemic here.
“A small outbreak of Nile Fever occurred in Andalucía in 2010, but since then, it has not reappeared in humans anywhere in Spain.”