Question 1
Will passing out bed nets—crucial as that activity is—eradicate malaria? Even if every person in the world slept under a bed net, mosquitoes would still thrive, because they feed off of animals, not just human beings, right?
Answer
Well, apparently with the exception of one species of mosquito that causes malaria in Macaques monkeys, the mosquitoes that feed off of animals are of limited public health importance.
Question 2
Okay, but even then, what about when people aren’t sleeping? People aren’t going to wear nets 24-hours a day, are they?
Answer
The Anopheles mosquitoes, the most dangerous ones, prefer to feed at night. So wearing bed nets during the day is not necessary.
Question 3
But, bed nets prevent mosquitoes from biting; they don’t kill the mosquitoes, right? I’m reminded of a story in Dan Fountain’s book, Health, the Bible and the Church, in which he describes a village in Africa that was tormented by lions. To prevent the lion attacks, the villagers erected a fence around the entire village. This was effective, but had they really solved the lion problem? A few days later a woman and two children went outside of the fence. Suddenly a lion attacked and carried off one of her children. The woman ran screaming back to the village, “Why can’t you get rid of the lions?”
Answer
Apparently the nets are treated with insecticide, so they do kill at least some of the mosquitoes that land on them, as long as those mosquitos haven’t developed a resistance to the insecticide.
Question 4
The most simplistic solution to malaria—one that my seven-year-old could have thought up— is to wipe out all the mosquitoes. Mankind has shown a remarkable albeit unfortunate effectiveness in driving other species into extinction. Why can’t we apply that same hunter’s ingenuity to mosquitoes? In the 19th Century, hunters nearly wiped out all of the bison in North America because their hides were so lucrative. Why don’t we make mosquito carcasses lucrative?
While this solution is simplistic, I’m not the first one to think of it. In 1996, Manila had a cholera outbreak that killed seven people and sickened 310 others. Health officials determined that flies and roaches were the culprits. So the city government decided to pay 4¢ for every ten dead flies and 6¢ for every ten dead roaches. Eliminating the insects before they infected people helped to end the epidemic. Could this be done with mosquitoes? A $100,000 grant from Bill Gates would buy a lot of dead mosquitoes.
Answer
Well, apparently this solution isn’t the panacea. When the British invaded India, they tried this same method with cobras. Unfortunately people started to breed cobras and once the British Colonists found out, they nixed the reward. Subsequently, the people released their cobras and they ended up with a bigger cobra problem than when they started.
Also killing off all the mosquitoes on earth is tricky. Many of the most successful efforts at eliminating them have involved the use of toxic chemicals like DDT, which has since been banned in many places because of its side effects.
The real question, however, is not can mosquitoes be eradicated, but should mosquitoes be eradicated? The downside to a world without mosquitoes is that other parts of the ecosystem will suffer. There are plants that rely on mosquitoes for pollination, fish that count them as their sole food source and even caribou depend on being bothered by swarms of mosquitoes in order to prompt their migratory patterns. It's unclear whether the plants and animals that depend on these pests would adapt and survive without them. Ridding the world of mosquitoes might save millions of human lives, but the environment would pay the price in more ways than one.
Question 5
So, what’s the solution?
Answer
The current strategy involves insecticide treated bed nets, draining standing water and spraying insecticides. This lowers the mosquito population enough so that sooner or later the malaria infected mosquitoes disappear from a given area, as happened in North America, Europe and much of the Middle East (though each of these regions had the advantage of DDT).
But unless mosquitoes (or more specifically the P. falciparum Plasmodium) are eradicated from the entire world, malaria could become re-established. As long as we have airplanes, a few cases each year will pop up even where malaria has been eliminated. In the U.S. alone there were almost 1,700 cases in 2010, and 2,000 in 2011, a 40-year high.
Thus we turn to vaccines. Perhaps the only real solution is to make all human beings immune to the disease through vaccinations, as happened with smallpox. Vaccines may be especially important in the face of mosquitoes that are becoming increasingly insecticide-resistant. As of this moment, a completely effective vaccine is not yet available for malaria, although several vaccines are under development. Bill Gates—who funds much of this research—recently said, "I'd be disappointed if within 20 years we're not very close to eradicating this globally."
In the end, it may require a completely new solution that we haven’t even considered. But I’ll leave that one to my seven-year-old.