Mosquitoes are widespread, occurring in all regions of the world except for Antarctica. In warm and humid tropical regions, they are active for the entire year, but in temperate regions, they hibernate over winter. Arctic mosquitoes may be active for only a few weeks as pools of water form. During that time, though, they exist in huge numbers and can take up to 300 ml of blood per day from each animal in a herd.
Mosquitoes carry terrible diseases, including: Malaria (which kills more than 600,000 people every year), dengue fever virus, Rift Valley fever virus, yellow fever, chikungunya virus, West Nile virus, Lymphatic filariasis, and Japanese encephalitis.
The deadliest of all is malaria, a parasitic infection that mosquitoes inject directly into our bloodstream when they bite. The parasites then travel to the victim’s liver, where they multiply and reproduce. Their babies travel the bloodstream, destroying the red blood cells.
This infographic was taken from gatesnotes