Dengue Track: How Mapping the Spread of Disease May Help to Stop It
Dengue is a notoriously malicious mosquito-borne virus that has seen an uptick in recent decades with the expansion of urban environments. But a new tool called Dengue Track is trying to change that.

Dengue fever causes flu-like symptoms, minor bleeding and a characteristic full-body rash. The disease used to be confined primarily to tropical regions, but the World Health Organization estimates that about half the global population is now at risk. It is rarely fatal but nonetheless constitutes a leading cause of illness and death among children in some developing countries. Though a vaccine has been developed, its use has only been approved in three countries so far, and it is not yet widely available anywhere.

Dengue is a disease that is uncommonly hard to fight. Because it has an incubation period of four to 10 days, mosquitos can be spreading it in an area for weeks before officials start to realize that they have an epidemic on their hands. What’s more, as globalization intensifies and people and goods travel more broadly than ever, it’s nearly impossible to keep infections localized or to judge where they might develop next.

Illnesses that, like dengue, are transmitted by blood-sucking insects are called “vector-borne” diseases, and when vaccines are not available, the only way to protect human populations is through methods known collectively as “vector control.” These include strategies for reducing the insects’ breeding areas, creating tools like nets to keep them away from vulnerable people or killing them with pesticides.

Vector control, however, is most effective when the movement of the disease can be plotted on a map. The trouble is that dengue, which is most prevalent in developing countries around the equator, is dramatically underdiagnosed and underreported, and systems to share what little information there is are inefficient, unstandardized, or nonexistent.

Dengue Track, a crowdsourced tool that tries to map the epidemiology of the disease, is an initiative from an organization called Break Dengue. Drawing information from cell phone conversations, social media, and an online chat system, it plots cases of the illness across the globe to try to predict where it may surface next.

It is a low-cost method that relies on tools common in developing countries, where only one-third have access to the internet but over 95 percent own mobile phones. This means that it is particularly well-suited to places where the national health system does not have the ability to track outbreaks itself.

“Thousands of lives are lost every year in developing countries for failing to detect epidemics early because of the lack of real-time data on reported cases,” said Lakshminarayanan Subramanian, a professor at New York University who helped to develop Dengue Track. This app might prove a useful model for identifying such epidemics early in the game and taking the appropriate steps to head them off.

Madeleine Read

Photo: Flickr

The theme of this year’s World Health Day, held annually on April 7th, was to promote the awareness of vector-borne diseases. Vector-borne diseases are transmitted through the bites of infected mosquitoes, flies, ticks and water snails, among other disease-carrying pests.

This year the World Health Organization (WHO) promoted the slogan “small bite, big threat,” in the hopes that they would be able to increase awareness on how people across the globe can protect themselves and their families from these pests and the viruses that they may transmit.

Vector-borne diseases have radically increased in the past few decades, aided by an increase in urbanization, international travel and environmental changes.

More than one billion people each year are affected by these diseases, which include malaria, dengue fever, Lyme disease, schistosomiasis and yellow fever.

Efforts to control the spread of these diseases have included the distribution of bed nets and insecticides, the use of body repellents and protective clothing, and the push for clean water and adequate sanitation.

WHO Director-General, Dr. Margaret Chan, noted, “A global health agenda that gives higher priority to vector control could save many lives and avert much suffering. No one in the 21st century should die from the bite of a mosquito, a sand fly, a blackfly or a tick.”

The focus this year is on dengue fever, which is currently the most rapidly spreading vector-borne disease in the world.

Dengue fever, also known as “breakbone fever” due to its symptoms, is a severe flu-like disease marked by vomiting, bleeding, body aches and difficult breathing. There is no known vaccine or cure available.

During the past 50 years, dengue fever has spread rapidly to more than 100 countries. Prior to 1960, dengue had seen some 15,000 cases, whereas now over 380 million cases of dengue fever persist.

The U.S. Centers for Disease Control and Prevention (CDC) is currently working on a vaccine for dengue fever in partnership with a company specializing in vaccine development, Inviragen. They have gone through clinical trials in a number of countries including Singapore, Colombia, Thailand and Puerto Rico, and analysis of those findings is still underway.

The International Federation of Red Cross and Red Crescent Societies is campaigning alongside the WHO to address this growing concern.

Previous programs to curb the spread of vector-borne diseases have proven successful, for example, the United States’ effort to combat malaria.

Malaria is the most deadly of vector-borne diseases, killing 1.2 million people every year. Multiple campaigns have been launched to prevent the spread of this disease, including the President’s Malaria Initiative (PMI) and the Global Fund to Fight HIV/AIDS, Tuberculosis and Malaria. PMI has distributed more than 120 million bed nets since 2006, as well as delivered more than 135 million doses of combination drug therapy.

These success stories provide hope for current efforts to control other vector-borne diseases such as dengue fever and schistosomiasis.

– Mollie O’Brien

Sources: Mission of the United States, Voice of America