Spain's National Association of Environmental Health Companies (Anecpla) has issued a warning over the rapidly spread of the black fly which carries serious diseases in sub-Saharan Africa, and Brazil and Venezuela, among other countries. The six-millimetre long pest does not currently carry serious diseases in Spain but it does leave victims with a nasty bite.
"The fundamental problem with this insect is that it bites in the form of a saw, causing a serious wound and can lead to infections and very alarming allergic reactions, which in some cases require hospitalisation," explains Anecpla's general director, Jorge Galván.
It starts by inoculating a small dose of anaesthetic, which allows it to bite without the affected individual noticing. Its saliva usually causes strong allergic reactions and severe pain in the area. The fly leaves victims with a welt of several centimetres that often bleeds, accompanied by severe swelling that can last up to a month.
If you are bitten by a black fly, it is important not to scratch it, as this can make the wound worse and cause it to become infected. It is recommended to apply ice to reduce inflammation, or a mild corticosteroid ointment. It is advisable to go immediately to the nearest hospital or health centre and report the case to avoid a worsening of the reaction.
The Spanish regions most affected by the presence of the black fly are Andalucía, Aragón, Catalonia, Madrid, Murcia and Valencia, where this native insect has grown to unprecedented numbers, mainly due to the increase in temperatures in recent years. It breeds in river beds.
"High temperatures are one of the main factors for a peak in the volume of the black fly population", explains Galván. "Their life cycle, which can last from a few days to several months, can be halved in very hot weather.”
The black fly is a transmitter of serious infectious diseases such as onchocerciasis, endemic in several countries in sub-Saharan Africa, Brazil and Venezuela, where according to the World Health Organization there are around 18 million people infected and around 270,000 have gone blind due to this disease, also known as 'river blindness'.