Holidaymakers visiting Spain are being warned to watch out for biting black flies which can SAW into the skin, and produce swelling that can last up to a month.
Health leaders say the black fly is "very close to becoming a major public health problem in Spain", and people who have been speared by the insect needed hospital treatment. In other countries, there have been reports of cases where people have gone blind due to the attack.
The Spanish regions most affected are: Andalusia, Aragon, Catalonia, Madrid, Murcia and Valencia.
Jorge Galván, the general director of ANECPLA, the environmental health association, has warned the insect can grow up to 6mm in length, adding it is: "Small in size and dark in colour, the virulence of the black fly bite is much greater than that of other insects.
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"The fundamental problem is that it does not sting but bites in the form of a saw, generating a significant wound and can lead to very alarming infections and allergic reactions, which in some cases require hospitalisation.
"The black fly bites, causing a small tear in the skin of its victim. It begins by inoculating a small dose of anaesthetic, which allows it to bite without the affected individual realising it."
Galván also alerted that: "Their saliva is what usually causes severe allergy symptoms and severe pain in the area. The final effect translates into a welt of several centimetres that usually even bleeds, accompanied by a high swelling that can last up to a month."
Other than causing blindness, reports have gone on to state that the black fly is a transmitter of serious infectious diseases such as river blindness, which is native to several countries in sub-Saharan Africa, Brazil and Venezuela.
ANECPLA says the black fly in Spain is currently not transmitting such a serious disease but has warned travellers that "due to both globalisation and the effects of climate change, it is a matter of time before it becomes so if adequate prevention measures are not carried out to control it."
Health experts have advised that if you do suffer from the black fly's bite, it is important not to scratch it, as it can worsen the wound and become infected.
It is also recommended to apply ice to reduce inflammation, or an ointment with a mild corticosteroid.
And, in worse case scenarios, it has been advised to go immediately to the nearest hospital, or health centre, and report the case to avoid a worsening of the disease.
