There are many different types of fleas, but the largest flea in the world is the giant human flea. This flea can grow up to 1/2 inch long and is usually found in tropical areas. The giant human flea is a bloodsucking parasite that feeds on humans and other mammals. These fleas can cause severe skin irritation and can transmit diseases to their hosts. If you think you have been bitten by a giant human flea, it is important to seek medical attention immediately.