Majority of insect bites are harmless, on some occasion they will cause discomfort. Fire ant, wasp, bee, and hornet stings usually hurt. Mosquito and flea bites usually itch. Insects can also spread disease through their bites or stings. In the U.S. some mosquitos spread the West Nile Virus. People who travel outside the U.S. may be at risk for malaria and other infections.