The World Health Organization (WHO) said that dengue, a tropical disease, is spreading so fast that it represents a “pandemic threat” after infecting an estimated 50 million. The organization believes that female mosquitoes are transmitting the disease.
But dengue can also be spreading through increased movement of people and goods, including carrier objects such as bamboo plants and used tires, as well as floods linked to climate change.
The viral disease, which affected only a handful of areas in the 1950s, is now present in more than 125 countries – significantly more than malaria, historically the most notorious mosquito-borne disease.
“In 2012, dengue ranked as the fastest spreading vector-borne viral disease with an epidemic potential in the world, registering a 30-fold increase in disease incidence over the past 50 years,” the WHO said in a statement.
Dengue causes flu-like symptoms that subside in a few days in some sufferers. But the severe form of the disease requires hospitalization for complications, including bleeding, that may be lethal.
There is no specific treatment but early detection and access to proper medical care lowers fatality rates below 1 percent, according to the Geneva-based WHO.
Vaccines for dengue are still in the research stage. One clinical vaccine trial in Thailand, developed by French drugmaker Sanofi SA, proved that it was only 30 percent effective.
Part of the problem is that there are four different serotypes of dengue virus that can cause the disease, which means that a vaccine must immunize against all four types to be effective.
Vaccination against only one serotype could lead to severe DHS when infected with another serotype due to Antibody-Dependent Enhancement.
It is estimated that a dengue vaccine will be available in 2014.