Five Facts You Need to Know about Aedes aegypti

July 14, 2016

In Oxitec’s Five Facts series, we explore the behavioral, biological and environmental characteristics of Aedes aegypti and show what makes these mosquitoes so dangerous and why they must be controlled and contained.

Fact 1: Females Are the Ones that Bite and Transmit Disease

Zika, dengue fever, chikungunya and yellow fever—the female Aedes aegypti mosquito is the primary vector for transmitting these dangerous diseases which affect hundreds of millions of people each year, contributing to the one million annual deaths caused by mosquitoes.

Female mosquitoes bite humans and use the nutrients in blood to produce their eggs. When they consume blood from an individual with circulating virus, the mosquitoes in turn become infected. Through biting many humans during their life time, female Aedes aegypti spread diseases (it only takes one bite for a virus to be transmitted).  Male mosquitoes do not bite and therefore do not spread disease.


How widely distributed is Aedes aegypti? Very: It is one of the most widespread invasive species globally and is commonly found in the United States.  What makes this all the more concerning is that long-standing approaches to mosquito control are becoming increasingly ineffective.

For example, insecticide resistance has made Aedes aegypti control extremely difficult in many parts of the world and these chemical-based methods may also have detrimental effects on the environment.

Oxitec, however, has developed a new, environmentally-friendly mosquito-control solution that’s showing promising results in controlling Aedes aegypti in places like Brazil, Panama and Grand Cayman. Read about it here.


Fact 2: Aedes aegypti Strike During the Day

Aedes aegypti isn’t your average mosquito. In fact, female Aedes aegypti carry and transmit dangerous, potentially fatal diseases including Zika, dengue fever, chikungunya and yellow fever (females bite and transmit disease, males don’t, by the way).

They also prefer to strike in the plain light of day. Two hours after sunrise and several hours before sunset are favorite times. Of course, they can bite at any time, and they present an increasingly urgent threat due to the growing prevalence and spread of mosquito-transmitted diseases globally.


While a wide range of vector control approaches exist, most have limited effectiveness on the urbanized non-native Aedes aegypti, are unproven in the field, or have potential adverse environmental impacts. Oxitec’s innovative solution targets only Aedes aegypti in an environmentally-friendly manner and has shown unparalleled results in field trials conducted outside the United States. Learn more about Oxitec’s solution.


Fact 3: Aedes aegypti are Becoming Resistant to Insecticides

Over a million people per day contract Zika, chikungunya and dengue.  The WHO estimates that as many as 4 million people will be infected with Zika by end of 2016.1 Although chikungunya only recently appeared in the Americas and the Caribbean, there were over 1 million infections within one year. And, according to the Centers for Disease Control and Prevention (CDC), there are an estimated 390 million dengue infections each year in over 125 countries.

Mosquito-borne disease prevalence is growing. Traditional mosquito control methods for Aedes aegypti are not sufficiently suppressing the mosquitoes and are becoming increasingly ineffective. In fact, Aedes aegypti has already developed resistance to many common insecticides, and this resistance is passed on to future Aedes aegypti generations.


Aside from their diminishing effectiveness, many insecticides have poor environmental safety records. Governments around the world are increasingly reluctant to use them, often issuing bans. With these approaches becoming less viable, a solution to suppress Aedes aegypti is urgently needed.

The Oxitec solution is a promising, innovative approach that is environmentally friendly and has delivered outstanding results in the field. Learn more about Oxitec’s solution.


Fact 4: Aedes aegypti Love Your Home Just as Much as You Do

When was the last time you left a half empty water bottle sitting out, or skipped cleaning out your gutters? Although you probably didn’t think twice about mosquitoes when doing so, you should have, because these are ideal breeding grounds for Aedes aegypti.  In fact, the mosquitoes can breed in pools of water as small as a bottle cap!

The dangerous Aedes aegypti mosquito species, whose females carry and transmit debilitating and potentially fatal diseases including Zika, dengue fever, chikungunya and yellow fever, is primarily an urban dweller. It not only prefers to live in and around human habitation, but also thrives and proliferates in these conditions. Aedes aegypti females feed almost exclusively on humans.


Aedes aegypti larvae are typically found in small, wet places, including discarded bottle caps, soda cans, cups and tires, as well as potted plants and vases. And their eggs can survive for six months or more without being in water. The adult mosquitoes rest in cool, shaded places in the home, such as wardrobes, laundry areas, cabinets and under furniture.

So what can be done to contain these dangerous disease carriers?

Unlike conventional vector control methods, which are failing to control Aedes aegypti, Oxitec’s solution targets this mosquito specifically and does not harm or persist in the surrounding environment. Read more about it here.


Fact 5: Aedes aegypti are Highly Invasive

Aedes aegypti not only carries and transmits diseases like Zika, chikungunya, dengue, and yellow fever, but it’s also incredibly invasive, spreading out of Africa and around the world in the last couple of centuries — thanks in part to its reproductive cycle.

Only the female mosquito feeds on blood, which is needed for egg production. Roughly three days after feeding, the mosquito lays her eggs in several locations over multiple days. A single female can lay around 100 eggs per blood feed and can produce up to five batches in her one to two-week lifetime.

Aedes aegypti eggs can stay dormant for over six months and hatch when submerged in water. This trait and the fact that a female can produce up to 500 eggs in her lifetime have created a mosquito that is highly able to spread and expand quickly, rapidly creating new areas of disease risk and transmission.


Research published in The Lancet suggests that 200 million Americans live in areas susceptible to seasonal Zika virus transmission.2 Given Aedes aegypti’s ability to transmit devastating viruses and the current lack of effective control methods, developing a solution to control and even eliminate this invasive, dangerous mosquito is urgent.

Oxitec has developed a biological, environmentally-friendly mosquito control solution that has shown promising results in places like Brazil, Panama, and Grand Cayman. Read about it here.