Sitting at the train station in Kuala Lumpur, I swat away the deadly malaria-ridden mosquitoes. They want my blood, in exchange for a well-known tropical disease made famous by Cheryl Cole. In the train station is a billboard showing an image of a person being bitten by a mosquito. It’s a squeamish photo and makes me feel uneasy. It grabs my attention, though, because instead of the malaria caption I was expecting to see underneath the image, I see the words DENGUE FEVER. A list of symptoms – severe headache; severe joint pain, vomiting, bleeding, rash and sudden, high fever – follows.
On the train, I see the headline “Dengue Death Tolls on the Rise” on the front of a local newspaper. I arrive in Ipoh, a town north of Kuala Lumpur. There are two shopping centres in the town, neither of which had any posters or billboards with the word ‘dengue’ printed on them. Newspapers follow the story, each one of them mentioning the seriousness of the disease and how to avoid becoming infected. But the concerns displayed on the pages of newspapers are not reflected in the town. Open drains and holes in the ground filled with stagnant water are commonplace and are often situated in parks full of people.
What is dengue fever?
Dengue fever is transmitted by the Aedes mosquito. Dengue is an RNA virus of the family Flaviviridae, genus Flavivirus. There are other not so well known killer viruses also belonging to this genus, such as yellow fever virus and West Nile virus. Dengue haemorrhagic fever, now known as severe dengue, may develop from an initial infection of dengue fever. Severe dengue was first discovered in the 1950s during epidemics in the Philippines and Thailand. Up to 100 million dengue infections occur every year and cases of dengue are now reported all over Asia and Latin America, putting almost half of the world’s population at risk. The fever is on the WHO’s list of 17 neglected tropical diseases, which does not include malaria.
There are four distinct serotypes (distinct variations between species of microbial life, such as bacteria and fungi) of dengue: DEN-1, DEN-2, DEN-3 and DEN-4. Each of these contain different genotypes. The “Asian” genotypes of DEN-2 and DEN-3 have associations with severe disease accompanying secondary dengue infections. Severe dengue is named so due to complications involving plasma leaking, fluid accumulation, respiratory distress, severe bleeding and organ impairment. If proper medical care is not taken shortly after experiencing these symptoms, the result may be fatal.
Infection and recovery
Once infected, humans serve as a source of the virus for uninfected mosquitoes, allowing speedy transmission via infected blood. This makes infected humans the main carriers and multipliers of the virus. The symptoms are visible after a four to ten day incubation period, after the person has been bitten by an infected mosquito.If a human recovers from infection of one dengue virus, they are protected by lifelong immunity against that particular virus serotype. It does not include protection from the other three serotypes and evidence suggests that repeated infections increase the person’s chance of developing severe dengue. There is no vaccination or specific medication to take once infected with the disease.
There is currently only one way to control dengue virus transmission. This is through integrated vector management (IVM), which includes the improvement of water storage practices to prevent egg-laying female mosquitoes from accessing water in human communities. It is vital that local authorities here make the first steps in destroying these breeding sites.
For a disease to get global recognition, it unfortunately seems that certain countries need to be threatened by the disease, or indeed certain people. The most famous dengue sufferer is Rihanna’s father and the most famous person to die from dengue is a surfer named Andy Irons.
The list of malaria sufferers is strikingly different. It includes JFK, Genghis Kahn, Mother Teresa, David Attenborough, Christopher Columbus, Michael Caine and Cheryl Cole. Dengue fever has become a growing problem in the Caribbean, a holiday destination favoured by many Europeans and Americans. It has begun to get some of the media attention it deserves since its increase in popular tourist destinations, but the same cannot be said for countries in Asia. What is it going to take for neglected tropical diseases like dengue to get the media coverage it deserves?
Illustration: Maria Kavanagh