Britain on high alert as hungry, toxic caterpillars spread

Britain is on high alert as an army of hungry and very toxic caterpillars is on the march. After first arriving in the UK in a shipment of oak trees from Holland to London in 2006, these critters have spread to most parts of the country in 18 years. Caterpillars cause dangerous allergic reactions like rashes, itching, and even Asthma.