Mosquito Wars

We’ve come a long way since the days of blaming the stars.

Malaria has terrorized humankind for thousands of years, but for most of that time, we had no idea what caused it. The ancient Greeks thought Sirius the dog star might be responsible. A Chinese medical text from 270 BCE speculated that three demons spread the disease. As recently as the mid-1800s, doctors believed malaria was caused by the stinky fumes that wafted into cities from nearby swamps (the word malaria means “bad air” in Italian).

Today, we know exactly who our enemy is: the mosquito. Doctors no longer subject malaria sufferers to unpleasant (and pointless) treatments like blood-letting and chewing tree bark. Most importantly, we’ve made massive progress in fighting a disease that as recently as 2000 killed nearly 870,000 people in a single year.

This progress is one of the most remarkable global health stories in recent years. Malaria claimed more than 429,000 lives last year, mostly in Africa and Southeast Asia. While that figure is still way too high, it represents a 50 percent reduction overall from the disease’s peak in the early 2000s. I don’t throw the word “miracle” around lightly, but that number is nothing short of miraculous.

How did we get here? I give credit to an unprecedented scale-up in global commitment and cooperation—malaria funding rose by 1,000 percent from 2000 to 2015. This money fueled a number of amazing scientific breakthroughs, enabled us to deliver them at scale, and focused more brainpower on improving both control and treatment efforts.

This October marks a decade since Melinda and I first called for eradicating malaria. It was a controversial move at the time, but the progress made since then has convinced many that this is a realistic goal (although some are still skeptical).

If I had known back in 2007 how much progress we would make in ten years, I would’ve been thrilled by how much we’ve cut the death rate. I’d also be impressed by how many insecticidal bed nets are now in use, how new treatments are helping people with the most severe cases of malaria, and how rapid diagnostic tests have made it easier to find and treat people. But it wouldn’t all be good news.

In 2007, I thought we’d have a long-lasting malaria vaccine by now. The WHO plans to begin pilot demonstration projects of a first-generation malaria vaccine in sub-Saharan Africa next year, although without a booster dose it only protects a child for less than six months. I’m hopeful that researchers will develop a next generation vaccine that offers much longer protection within the next 10 years, but a decade ago I was overly optimistic about where we’d be today.

There are still plenty of reasons to believe we can eradicate malaria, though. In the war against malaria and the mosquitoes who carry it, we’re already fighting on every front. Consider the wide array of innovations in development right now:

New Insecticide-Treated Bed Nets: The older generation of bed nets needed to be soaked in a special insecticide solution every six months. The long-lasting nets we will distribute in Mozambique through our giveaway protect people from mosquitoes for three years and can even be washed when they get dirty. Unfortunately, some mosquitoes are now developing resistance to the pyrethroid insecticides used in these nets—so researchers are working on next generation bed nets that use combinations of insecticides and appear effective against all mosquitoes, including insecticide-resistant ones.

Tackling Drug Resistance: In Southeast Asia, we’ve seen some types of the malaria parasite develop resistance to the drug combinations we use to cure and prevent the disease. If this drug resistance spread to Africa, it’d be a disaster. Fortunately, we have partners on the front lines finding ways to fight back. Watch this VR video about the amazing work one team of researchers is doing to combat drug resistance in Thailand:

Disease Mapping: We know more today about where malaria is occurring than we have at any other point in history. Public health experts are combining anonymous data from mobile phone records with data on malaria incidence to track the movements of infected mosquitoes. That's super valuable, because it helps countries use their limited resources in places that have the highest disease burden.

Eave Tubes: Many houses in hot climates have a gap between the roof and the walls to keep the inside cool. By sealing these gaps and inserting special tubes just below the roofline, air still flows into the house but keeps mosquitoes out with a mesh filter. Since the tubes are too high for children to reach them, the mesh can be coated with a high enough dose of insecticide to kill even insecticide-resistant mosquitoes.

Genome Editing: Our foundation has invested a lot of money into editing the genetic code of mosquitoes. We’re still in the very early stages of development, but scientists are exploring whether this technique could one day render a small number of key mosquito species infertile or unable to carry the malaria parasite.

Attractive Targeted Sugar Baits: Only female mosquitoes bite people, and they only do it when they’re breeding. The rest of the time, they rely on sugar for energy. These calendar-sized traps hang on the outside of homes and contain a minimum risk toxin that kills more than 95 percent of the mosquitoes that flock to their sweet scent without affecting pollinators. Trials are underway in Mali.

I think we will see an end to malaria in my lifetime. It’s a preventable and curable disease, and the public health community has already demonstrated that it’s possible to shrink the map and save lives. These new tools in the development pipeline will play a huge role in reaching our goal. While we’re still decades away from wiping malaria off the map for good, one thing is clear: the mosquito has met its match. (Source: gatesnotes)