It’s one of the most relentless stalkers on Earth, using a tiny, needle-like probe to sip its victims’ blood. It dines almost exclusively on humans and never ventures far from where they live, laying eggs in bottle caps, used tires and flower pots. It fits easily onto a single fingernail, and yet has tormented armies and obliterated the population of entire cities.
Thousands of species of mosquitoes inhabit the planet, but few have proved more resilient — or more deadly to humans — than the Aedes aegypti. It has fueled a long list of epidemics across the globe: Dengue fever. Yellow fever. Chikungunya. And now, Zika.
“It’s one of the most efficient killers in the world,” said Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine.
The Aedes aegypti caused a punishing outbreak of yellow fever in the 1890s that hastened the French to abandon construction of the Panama Canal. It sickened thousands of soldiers during the Spanish-American War. It was behind deadly yellow fever outbreaks during the 19th century in New Orleans, Hampton Roads in Virginia and Memphis. Even now, it infects an estimated 20 million people around the world with dengue fever each year.
The mosquito, which is found in regions that are home to more than half the Earth’s population, has evolved to thrive in the places where humans congregate — particularly dense, urban environments. It can breed in the smallest spots in and around homes. Its larvae don’t necessarily need water to survive, and eggs can lay dormant for a year or more, only to hatch once submerged in water.
“It’s one of those pests, like cockroaches, that has evolved over the last 15,000 years to exploit changes in human behavior and habitation,” said Ronald Rosenberg, acting director for the Division of Vector-Borne Diseases at the Centers for Disease Control and Prevention, at a conference last week.
Females — they are the only ones that bite — typically lay 100 to 200 eggs after each meal and can produce numerous batches of eggs in a lifetime.
Aedes aegypti mosquitoes are aggressive daytime biters
. They can hide under beds, in closets or other shady places. They also are “sip feeders,” meaning they feed often and on multiple hosts — a practice that makes it possible to quickly spread disease.