In 1897, a British doctor named Sir Ronald Ross made a game-changing discovery which ultimately led to smarter ways to prevent dengue fever – even if that wasn’t his primary intention at the time.

Born in India, Ross had become fascinated by malaria, a disease he had seen kill thousands of people during his 25 years in the Indian Medical Service.

At the time, it was unclear how malaria was spread. It was Ross who found that female mosquitoes (of the Anopheles genus) were to blame for transmitting the malarial parasite. That flash of insight changed how we think about mosquitoes, disease transmission, and prevention.

Ross won the Nobel Prize for Physiology or Medicine in 1902. (He was, incidentally, a bit of an all-rounder: he was a doctor, a poet, a novelist, and a songwriter. And an artist. And mathematician!)

This was an exciting time for medical research. Just a few years later in 1906, it was confirmed that dengue fever was spread by the Aedes aegypti mosquito. The following year, dengue became the second disease (after yellow fever) that was shown to be caused by a virus.

It must have seemed as though scientists were on the verge of figuring out mosquito-borne illnesses once and for all. But, alas, it wasn’t so simple.

Happy anniversary?

Winning the Nobel Prize meant that Ronald Ross’ contribution to medicine would never be forgotten. But, just in case, he made sure his discovery would be celebrated every year by declaring August 20 to be World Mosquito Day.

The day is marked with a series of events, led by the London School of Hygiene and Tropical Medicine. This year, the school is even hosting a play about Ross and his work.

So where are we today? Far more is known about how vector-borne diseases like dengue and malaria are transmitted, yet millions of people still suffer from them.

Perhaps reflecting on how far we’ve come in a little over a century will inspire new breakthroughs – just like the moment Ronald Ross discovered that those tiny mosquitoes were causing some of our biggest problems.

On August 20, we’ll be posting an interview with a leading dengue researcher at the London School of Hygiene and Tropical Medicine.  

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