The commensal rodents as we know them are an introduced species into the West Indies. They came with the first explorers from Europe and the first slaves from Africa and were spread not only in the West Indies but North and South America as well. The first record of attempts at their control was in Barbados in the 1700s when two pence was paid for each rat caught. Active control has been going on in the islands since the 1960s and 1970s with only partial success. The Pan American Health Organization is now assisting many of the governments with their problem and programs.