Diseases Back from the Dead: Dengue Fever
In the 1960s, health authorities thought they could finally breathe a sigh of relief. Through mosquito-control efforts, they had nearly eliminated dengue fever, a viral disease found in the tropics. Suddenly in the ’70s, it began to reappear. Outbreaks started cropping up across Latin America, and they just got worse. In 1998, there was a pandemic of dengue fever and its much more severe cousin, dengue hemorrhagic fever. More than a million cases were reported in 56 countries; now, more than 100 million cases occur every year.
Most people with dengue fever don’t have symptoms. The virus simply uses them as carriers. When the disease finally strikes, it starts as a sudden fever, often as high as 104, 105 degrees. Two to five days later, the victim is covered with a red rash, accompanied by headache, fatigue, vomiting, and joint and muscle aches. Most people recover, but a small number of dengue fever cases develop into dengue hemorrhagic fever, which starts out like dengue fever but then causes a shock phase that kills half its victims. There is no cure for dengue fever, and no vaccine to prevent it.
Dengue used to be a disease of poorer areas, Heymann says. But in India, for example, it became a middle-class disease when mosquitoes bred in the air-cooling systems of peoples’ houses, causing major outbreaks. “Anywhere there are mosquitoes that can transmit a disease, they’ll transmit it,” says Heymann. And the age of air travel means that the range of diseases like dengue has become huge. “It’s really interesting to follow dengue as it has spread throughout the world,” Heymann says.