The mosquitoes are a family of small, midge-like flies: the Culicidae. Although a few species are harmless or even useful to humanity, most are considered a nuisance because they consume blood from living vertebrates, including humans. The females of many species of mosquitoes are blood-eating pests. In feeding on blood, some of them transmit extremely harmful human and livestock diseases, such as malaria, yellow fever and filariasis. Some authorities argue accordingly that mosquitoes are the most dangerous animals on Earth.
Female mosquitoes have piercing mouthparts through which they extract the blood of a host. The protein from gathered blood is used in egg production. Male mosquitoes do not have the ability to extract blood from a host.
While not particularly painful, the bite of a mosquito can prove dangerous to humans through disease transmission. When a mosquito inserts her proboscis through the skin, her saliva creates a small, red bump. These bumps produce mild to severe itching. Some people may become less sensitive to mosquito saliva through repeated exposure, while others may develop allergic reactions. Symptoms of an allergy include blistering and inflammation, as well as asthmalike reactions. Mosquitoes also carry diseases such as yellow and dengue fevers, malaria and encephalitis and are capable of passing them from host to host.