Families should drain paddling pools to fend off bloodsucking horseflies, experts have said, amid a surge in reports of bites that can lead to potentially deadly infections.
The insects – also known as clegs – are flourishing in Britain’s longest heatwave in 40 years, according to scientists.
Calls to the NHS 111 helpline about insect bites last week were nearly double the average for this time of year, while doctors have reported patients needing hospital treatment for resulting infections.
The British Pest Control Association (BPCA) advised the public to remove standing water, in which the insects thrive, from their gardens.
More than 9,000 people called the 111 helpline about insect bites last week, nearly twice the baseline figure, according to NHS England data.
Dr Nick Scriven, president of the Society for Acute Medicine, told the BBC: “We wouldn’t normally see anyone coming to hospital for a bite, but we have seen a few recently needing treatment with antibiotics, which is very unusual.
“A couple of these were infected bites from horseflies. They actually give one of the nastier bites, because they take a chunk out of you.
“They can be very painful, and can take a while to heal, and as result can get infected and need antibiotics. In the worst-case scenario, they can cause cellulitis, an infection of the skin.”
Antibiotic Research UK said the “horsefly bite epidemic” demonstrated the need for Britain to develop new medications “to keep up with our changing climate”.
“It is entirely possible in 2018 that you can die of an insect bite, not just in some hot foreign clime, but here in Britain,” the charity’s chief executive, Professor Colin Garner, said.
“We have not invested in the kinds of antibiotics we need to keep up with devious and ever-changing bacterial infections.”
The effects of an infected horsefly bite can include a raised and nasty rash, dizziness, shortage of breath, and weak and swollen limbs.
NHS guidance advises visiting your GP if an insect bite results in symptoms of an infection such as pus, increased pain, redness and swelling.
“Horsefly bites are particularly painful because their main food source is livestock, which have a limited ability to move the fly away,” said BPCA field officer Natalie Bungay.
“This means they can take their food without having to worry about delivering a painful bite, as the animals are generally powerless to stop them.
“This is as opposed to mosquitoes, which extract blood through a painless bite.”
The BPCA said horseflies were more likely to be a problem in rural areas, where they have access to standing water in troughs, ponds and marshes, which provide a food source and breeding environments.