Like so many ailments, it begins with a fever. A crushing headache grips the afflicted, creating blurry vision alongside other trademark symptoms like joint pain, sick stomach, skin sensitivity, and extreme fatigue. After the first 24 hours, the fever won’t break and has soared past 102 F.
Luckily, it’s just a mild case of the mosquito-transmitted virus known as dengue. It’s the fastest-spreading tropical disease in the world, but unlike fellow vector-borne diseases like West Nile and Zika, dengue is much more dangerous.
Known in Africa and South America as “breakbone fever” due to the pain it inflicts, dengue carries an average mortality rate of up to 20 percent for untreated patients who develop hemorrhagic symptoms.
A second infection increases the likelihood of developing internal bleeding and pushes the mortality rate of untreated cases to 50 percent.
By comparison, even the most damaging strains of COVID-19 carry an average fatality rate of less than 5 percent.
The rapid territory expansion of the mosquito that carries dengue—Aedes aegypti—has allowed dengue and similar viruses to spread alarmingly fast in places not normally associated with equatorial diseases, like the United States.