New mutant bed bugs twice as hard to kill By Claire McKim Published on Sunday 15 April 2012 00:00 MUTANT bed bugs are becoming increasingly difficult to kill, leading to a rise in infestations in Scottish homes. Experts are warning that genetic mutations of the household pests have developed a resistance to the most commonly used insecticides, making them twice as hard to exterminate. One pest control firm said it had seen a 1,200 per cent rise in the number of reported bed bug infestations across Scotland in the past ten years. The Royal Environmental Health Institute in Scotland now says they are a "major public health issue" in Scotland, with homes in affluent areas as much at risk as poorer dwellings. Bed bugs - Cimex lectularius - are parasitic insects that prefer to feed on human blood. They can cause bites, skin rashes and allergic symptoms. Gavin Lindsay, manager at Anglo Scottish pest control, said: "Ten years ago we had two or three calls a year to treat bed bugs and now it's easily seven calls a week. Bed bugs are everywhere and can affect anyone. We are finding bed bugs are becoming immune to the insecticides we use and it often takes twice as many treatments to kill them. Tom McLery, contract supervisor at Total Pest Solutions (Scotland), added: "We have recently had to change our products because we have found it more difficult to control bed bugs. At the moment we are using a stronger level of our active ingredient. Whereas before it would take two treatments to get rid of them, we are finding it is now taking at least three or four sessions. Michael Siva-Jothy, Professor of Entomology at University of Sheffield, said scientists and policy makers are in talks over the best way to treat the bed bug problem. He said bed bugs could soon become resistant to all existing treatments. Bed bugs are becoming resistant to the most commonly used insecticides, called pyrethroids. If you go out to infested houses you will find these bugs are very resistant to standard chemicals. What we are seeing here is evolution in action; genetic changes in bed bugs produce resistance to insecticides and in many cases patterns of pesticide use by home owners and pest control companies is making the situation worse. There is a big problem with home owners and pest controllers using increasing doses of the same pesticide to kill bed bugs. In the long term this will just make them more resistant. We don't want to end up with a situation where bed bugs become resistant to all our available treatments. The professor explained that more education was needed to help people spot bed bugs. People often don't realise they have bed bugs until it's too late. A lack of education means people don't know what they look or smell like. If more people could identify them they could track them down more easily, stop infestations growing and stop them from spreading. Fully grown bed bugs are around 5mm long and leave clusters of dark brown or black spots on surfaces. They can also exude a subtle, sweet and musty odour. Bed bugs prefer tight crevices and dark locations where they can remain hidden, so they are also often found in wall sockets, floorboards, within furniture and behind wallpaper. Sleep tight: Signs you may have bed bugs Itchy red bumps that appear on your body Black dots that appear on your sheets, blankets, pillow cases and mattresses Blood stains on bed linen, blankets and mattresses Dried remains of shed skin or dead bugs on your bed or in your bedroom Seeing evidence of the bugs themselves - bed bugs are a brownish-red colour and can grow to around 5mm