• Dengue fever symptoms range from headache and nausea to severe organ dysfunction.
  • The disease is found in more than 100 countries throughout the tropics.
  • Dengue is the world’s fastest spreading mosquito-borne disease.
  • The World Mosquito Program describes its Wolbachia method as safe and sustainable.

Mosquitoes are helping scientists tackle a lethal virus for which there is no effective vaccine or treatment.

Dengue fever causes up to 400 million infections a year and can lead to serious illness and death. It’s now the fastest spreading mosquito-borne disease in the world.

Now a trial in Indonesia has seen a 77% drop in dengue fever cases after mosquitoes were infected with a bacteria commonly found in insects. It’s called Wolbachia and it reduces a mosquito’s ability to spread dengue, by making it harder for the virus to replicate.

There are around 8 million dengue cases a year in Indonesia. The trial took place in Yogyakarta, a city on the island of Java. Mosquitoes hatched from five million eggs infected with Wolbachia were released across half of a 26km2 urban area housing about 300,000 people.

A trial in Indonesia by the World Mosquito Program has seen a dramatic 77% drop in dengue fever cases
A trial in Indonesia by the World Mosquito Program has seen a 77% drop in dengue fever cases
Image: World Mosquito Program

The World Mosquito Program, which is working in 11 countries to help reduce the impact of mosquito-borne diseases, said the results of the trial, published in The New England Journal of Medicine, have “significant implications” for the 40% of the world’s population at risk of dengue.

“This is the result we’ve been waiting for,” said Professor Scott O’Neill, director of the World Mosquito Program. “We have evidence our Wolbachia method is safe, sustainable and dramatically reduces incidence of dengue.”

As the chart below shows, the success of the trial in Indonesia has been replicated in a number of countries where similar studies have taken place.

Trials using Wolbachia-infected mosquitoes have proved successful in a number of countries.
Trials using Wolbachia-infected mosquitoes have proved successful in a number of countries.
Image: World Mosquito Program

Rapid growth

According to the World Health Organisation (WHO), reported dengue cases have grown eight-fold in 20 years. Before 1970, only nine countries had experienced severe dengue epidemics.

The disease is now regularly found in more than 100 countries throughout the tropics, where it is a threat to nearly half the world’s population, the WHO says. Affected countries in 2021 include Brazil, Colombia, Fiji, Kenya, Paraguay and Peru.

What is the World Economic Forum doing about epidemics?

Epidemics are a huge threat to health and the economy: the vast spread of disease can literally destroy societies.

In 2017, at our Annual Meeting, the Coalition for Epidemic Preparedness Innovations (CEPI) was launched – bringing together experts from government, business, health, academia and civil society to accelerate the development of vaccines against emerging infectious diseases and to enable access to them during outbreaks.

Our world needs stronger, unified responses to major health threats. By creating alliances and coalitions like CEPI, which involve expertise, funding and other support, we are able to collectively address the most pressing global health challenges.

Is your organisation interested in working with the World Economic Forum to tackle global health issues? Find out more here.

What dengue fever does

At its mildest, symptoms include fever, headache and nausea. More severe symptoms can include severe abdominal pain and persistent vomiting. Life-threatening complications can include severe organ dysfunction.

Severe dengue is a leading cause of serious illness in some tropical countries and needs intensive care by experienced medical professionals.

With COVID-19 putting health systems under huge risk, the WHO has stressed the importance of continuing to tackle diseases like dengue, especially as case numbers surge.

“The combined impact of COVID-19 and dengue epidemics can potentially result in devastating consequences on the populations at risk,” WHO says.

The virus is transmitted to humans through the bites of infected female mosquitoes, primarily the Aedes aegypti mosquito, which also spreads viruses including yellow fever, chikungunya and the Zika virus.