According to the British Pest Control Association (BPCA), cockroaches can be “vectors of disease” - and a new study has revealed how they are evolving to become even more difficult to kill. The study was conducted using German cockroaches, which are one of the two main species of cockroaches found in the UK. What did the study find? The study was led by Professor Michael Scharf, who has found evidence that shows German cockroaches are developing cross-resistance to insecticides, making them difficult to exterminate. Scharf said, “Cockroaches developing resistance to multiple classes of insecticides at once will make controlling these pests almost impossible with chemicals alone.” The study found that cockroaches that survived a treatment of insecticide would pass off an immunity to their offspring. “We would see resistance increase four - or six-fold in just one generation,” said Scharf. “We didn’t have a clue that something like that could happen this fast.” The study The research team set out to test the methods that exterminators rely on to dispose of a cockroach infestation. Exterminators will use a mixture of insecticides from different classes in the hopes that, even if some cockroaches are resistant to some insecticides, they won’t be resistant to all of them. The study therefore consisted of three different approaches to testing: In one treatment, three insecticides were selected and used in rotation each month for three months, which then repeated itselfIn the second test, the use of two insecticides from different classes was used for six monthsIn the third one, the insecticide that the cockroaches had a low-level of resistance to was chosen and used throughout the study For each test, the cockroaches that were used prior to the study were lab-tested in order for the scientists to use the more effective insecticides in each treatment. Scharf said, “If you have the ability to test the roaches first and pick an insecticide that has low resistance, that ups the odds. But even then, we had trouble controlling populations.” Are cockroaches dangerous? The BPCA states that cockroaches are “capable of carrying the organisms which cause food poisoning in humans”. Pest World explains, “Cockroaches have been implicated in the spread of 33 kinds of bacteria, including E. coli and Salmonella species, six parasitic worms and more than seven other types of human pathogens. “Cockroaches have many negative consequences for human health because certain proteins (called allergens) found in cockroach feces, saliva and body parts can cause allergic reactions or trigger asthma symptoms, especially in children.” How to keep your home clear of cockroaches In order to keep yourself and your family safe from cockroaches and the bacteria they carry, prevention is the key. The BPCA recommends these measures: Keep all areas clean and tidy. They thrive in homes, gathering in warm areas like pipes, stoves and sinksTry not to leave dirty dishes and utensils under the sinkKeep bins covered, clean and make sure you empty them regularlyAreas like on top or underneath your fridge are warm and can collect pieces of food which attract cockroaches, so be sure to clean these placesSeal the gaps around doors, windows and where any utility lines enter into the home to minimise areas that cockroaches can use to get into your houseIf you have any leaks beneath a sink, be sure to get this repaired as cockroaches could use this as a water source This article originally appeared on our sister site Sunderland Echo