Mosquitoes are small flies of the family Muscidae. Most species of females are ectoparasites whose tubular mouthparts (called long noses) pierce the skin of the host and consume blood. The word "mosquito" (made up of Mosca and the tiny ITO) is the Spanish word for "little flies.". Thousands of species feed on the blood of various hosts (mainly vertebrates), including mammals, birds, reptiles, amphibians and even some fish. Some mosquitoes also attack invertebrates, mainly other arthropods. Although the loss of blood means little to the victim, the mosquito's saliva usually causes a irritating rash, which is a serious nuisance. More seriously, however, many kinds of mosquitoes are also vectors of disease. When transmitted between hosts, some viruses can spread extremely harmful infections, such as malaria, yellow fever, chikungunya fever, West Nile virus, dengue fever, filariasis, Zika virus and other arboviruses, making them the most deadly animal family in the world.

Mosquitoes are members of the family nematodidae: Cucurbitaceae (from the Latin qulix, the exophytic qulich, meaning "mosquito" or "GNA"). On the surface, mosquitoes are similar to crane flies (tip family) and tip insects (chi family). In particular, females in many species of mosquitoes are risk vectors for blood eating pests and diseases, while members of the similar looking Ron and tip families are not. Many kinds of mosquitoes are not bloodthirsty, and many people produce "high to low pressure" in their blood to get it without spreading the disease. In addition, in bloodsucking species, only females do. In addition, even among mosquitoes carrying major diseases, not all species of mosquitoes, nor all strains of a given species transmit the same kind of disease, nor in the same circumstances. Their habits are different. For example, some species attack people in houses, while others prefer to attack people walking in forests. Therefore, in the management of public health, it is important to know which species or even which one a mosquito is dealing with.

More than 3500 species of mosquitoes from all over the world have been described. Some mosquitoes that bite humans are often vectors of multiple infectious diseases that affect millions of people every year. When the habitat of animals is disturbed (e.g. due to sudden deforestation), other animals that do not normally bite people but are vectors of animal diseases may become catastrophic factors for zoonoses of new diseases.