An outbreak of toxic caterpillars that can cause asthma attacks, vomiting and skin rashes has descended on London, officials have warned. Oak processionary moths (OPM), which are in their larval stage, have been spotted across the south-east of England and in the capital. Hairs on the caterpillars can cause fevers and eye and throat irritations, the Forestry Commission said. The organisation has issued a caution not to touch the species. …As a caterpillar, each OPM has about 62,000 hairs, which they can eject. Hairs that fall to the ground can be active for up to five years. The moths only live for two to three days in July or August. It is thought that the moths were brought into the UK on trees imported from Europe for a landscape project.