Over the past century, researchers have learned a great deal more about malaria, including how it spreads. They know that of the 3,500 species of mosquitoes, only about 40—all belonging to one group, Anopheles—transmit the disease to humans.
The spread of malaria begins when an infected person is bitten by a female Anopheles mosquito. (Males don’t spread malaria because they don’t feed on blood.) The mosquito uses its needlelike mouth to pierce the person’s flesh. During its “blood meal,” the mosquito gorges itself on the blood of the infected person. Then it flies away.
Days later, when the mosquito is ready for its next meal, it lands on a new person. As the mosquito jabs that person’s flesh, malaria parasites called Plasmodium enter the new victim’s blood.
In this way, bite by itchy bite, about 230 million people are infected with malaria each year. People who live in rural parts of developing countries, where medical care is often difficult to access, are most vulnerable to malaria. Those who become sick suffer high fevers, bone-rattling chills, and painful muscle aches. Most recover—but not all.
In 2021 alone, malaria killed an estimated 619,000 people across Africa, Asia, and Central and South America, according to the World Health Organization. In Africa, where most cases occur, the majority of deaths are among children younger than 5.