Mosquitoes keep me up at night.

If you ask someone about what things scare people the most, there’s a list of usual suspects: shark attacks, heights, enclosed spaces, etc. Mosquitoes usually don’t make the cut—but they frighten me more than almost anything else.

This fear might be a bit irrational in Seattle, where I live. Our climate is too mild for the types of mosquitoes that harbor serious diseases. In other parts of the world, however, families have good reason to be afraid. Mosquitoes and the diseases they carry kill more than half a million people every year. Consider this mind-blowing statistic:

Of all the illnesses mosquitoes spread, malaria is the worst by far. More than 200 million people suffer from it every year, and a child dies from malaria every other minute of every day. If you survive, it can leave you vulnerable to other debilitating diseases and chronic anemia. It’s an awful, painful disease (I wrote about what it feels like to have malaria a couple years ago).

Melinda and I encounter a lot of suffering through our work, but one of the worst things I’ve ever seen is a child having seizures from cerebral malaria in Tanzania. I will never forget watching his small body twist in agony, as his parents waited to find out if he would survive. I wouldn’t wish that experience on anyone.

So why exactly are people more afraid of sharks than mosquitoes? The late Hans Rosling would argue that humans are hardwired to fear things that cause us physical harm. This instinct is practical if you live in poverty (on level 1 or 2), where an animal attack is more likely to kill you. But if you can afford life-saving healthcare, it can distort your perception of how significant a threat really is.

Even if you know that you’re 50,000 times more likely to get killed by a mosquito than a shark, human instinct wins out. A photo of a shark attack victim on the evening news evokes a visceral reaction, because the threat is obvious. A picture of a malaria victim in a hospital ward doesn’t trigger our fear instinct in the same way.

Despite this, I’m determined to spread the word about mosquitoes—which is why I’m bringing back Mosquito Week here on Gates Notes.

Everything I’m posting this week is dedicated to my least favorite pest. You can read some good news about a country that hopes to eliminate malaria by 2020. You can see how the bed nets the Mozambique Ministry of Health and World Vision distributed last year on behalf of the Gates Notes Insider community are making a difference. I’m going to be talking about mosquitoes on my social channels all week, and I hope you’ll join the conversation.

As long as Hollywood keeps making blockbusters about sharks, I’ll keep talking about why everyone should be more scared of a tiny bug than a 3,000-pound carnivore. Jaws is nothing compared with the flying terror that is a mosquito.