Mosquitos and Zika: the insect behind the outbreak

A major problem with the current Zika break is that there is, at present, no vaccine for the virus. Researchers worldwide are stepping up efforts toward a vaccine, but such research invariably requires a lot of time and money. For now then, the focus on tackling the disease turns elsewhere.

 Following an Emergency Committee meeting, the World Health Organization (WHO) Director-General, Dr. Margaret Chan stated that the most important protective measures to be taken were "the control of mosquito populations and the prevention of mosquito bites in at-risk individuals, especially pregnant women."

The mosquitos that are behind the transmission of the Zika virus are those belonging to the Aedes species, namely Aedes aegypti and Aedes albopictus. These mosquitos spread the virus by feeding on people already infected with Zika, becoming infected themselves and then passing the virus on when feeding on another human.

In this spotlight, we take a look at why mosquito-borne diseases such as those spread by the Aedes species have risen to prominence, as well as examine methods that are being suggested for halting the spread of these worrying viruses.

"There's just so many factors," she explained, "like climate change, increased travel and increased urbanization."

• Climate change: "A lot of these mosquitos prefer warmer climate, so as the climate becomes warmer, they will become prevalent so to speak," said Sirohi. Richard Duhrkopf, an expert on mosquitos and associate professor of biology at Baylor University in Waco, TX, believes that "as the weather warms up and there is a greater flow of the virus into the [US], I am confident we will see transmission this summer."
• Increased travel: According to WHO, Aedes aegypti mosquitos will spend their lifetime in and around the area that they emerge as adults, with studies indicating that they usually fly an average of 400 meters in their lifetimes. As a result, it is the movement of humans rather than mosquitos that is behind the spread of the virus. "As people travel, these mosquito-borne viruses travel with them," explained Sirohi, and upon returning home mosquitos endemic to their region can pick up with viruses and begin transmitting them.
• Increased urbanization: Densely populated cities, such as those in Brazil where the Zika virus has spread, provide ideal conditions for virus transmission. "If people are very close together as they are in metropolitan areas, they are more likely to encounter an infected mosquito," Sirohi said. Buildings also protect mosquitos from the weather, increasing their longevity.