Prior to this, the Americas were filled with mosquitoes, but none carried the malaria parasite. Almost immediately, malaria moves from the colonizers' bodies to the mosquitoes, where it begins to spread as a sickness called "ague." Unlike Northern Europe, where wetlands have been plowed under or where the climate is not as amenable to the mosquito, the Americas are filled with wild wetlands and multiple species of mosquitoes. Malaria spreads quickly.