by DWYER GUNN
We recently solicited your questions for Sonia Shah, author of The Fever: How Malaria Has Ruled Humankind for 500,000 Years. Her responses cover the effect of Rachel Carson and Silent Spring on malaria; bed nets and their alternatives; and the history of malaria in the U.S. Thanks to Sonia and everyone who participated.
“[M]osquitoes infect between 250 million and 500 million people with malaria every year”?
Is there an extra zero in there somewhere? That number is way too high, since even on the low end everyone in the entire world would have malaria in 30 years. From the CDC:?”WHO estimates that in 2008 malaria caused 190 – 311 million clinical episodes.” This is within the lower bound of the range, but they use the word clinical episode whereas you use the word infect. There isn’t a good link for defining what a clinical episode is, but it appears to be a period of time in a clinic – which means that if you have a disease that isn’t cured, every time you visit a doctor is a clinical episode. It looks like there are perhaps 500 million people with the disease, which is a very high number but does not indicate such a high infection rate, unless everyone is cured of the disease every year. –Jon L.
No extra zeros. Hundreds of millions of people indeed sicken with malaria every year. The illness doesn’t last long, and many people suffer multiple episodes every year. In a highly endemic locale like rural Malawi, a child might suffer twelve episodes of malaria before the age of 2!
The greatest predator of mankind is the mosquito. It is the the top vector for infectious disease. Mosquitoes are mankind’s greatest pest.
Can an environmentalist morally defend the eradication of the mosquito? What would a world without mosquitoes look like? Should we “Save the Mosquito”? – Drill-Baby-Drill Drill Team
Not so fast. Fighting malaria doesn’t mean war on all mosquito-kind. Mosquitoes consider malaria parasites unwanted intruders, just like we do, and their immune systems instinctively attack the parasites. Most successfully ward it off, and so, while we may find them quite annoying, we cannot blame them for malaria. It’s only about a dozen species of mosquitoes-all from the genus called Anopheles-that allow malaria parasites to roost in their bodies, infecting hundreds of millions with malaria every year.
Conservationists need not worry about these dozen species, either. To wipe out malaria, we don’t need to kill them all-just the malaria-infected ones. These tend to be the elderly mosquitoes anyway, for it takes the malaria parasite over a week to develop sufficiently to make the mosquito infective.
Freakonomics for more