May 16, 2023
As the rainy season deposits pools of standing water across Ho Chi Minh City, it is worth reviewing the state of play with Dengue Fever.
Dengue is a virus spread by the Aedes mosquito (malaria is spread by Anopheles). It is a leading cause of illness across Latin America, Southeast Asia and the Pacific Islands. There are an estimated 400 million infections annually across the globe, of which approximately 500,000 cases develop into the more severe version known as Dengue Hemorrhagic Fever (DHF). These DHF cases will result in about 20,000 deaths – mostly among children.
Symptoms typically begin three to 14 days after being bitten, and may include high fever, headache, vomiting, muscle and joint pains, followed by itchy skin and a rash. Eighty per cent of first infections are asymptomatic or consist only of a mild fever. Those unlucky enough to get DHF may have severely low platelet counts, with bleeding, blood plasma leakage, and may even progress to Dengue Shock syndrome. The platelet count only starts to pick up again a day or two after the fever resolves.
There are no specific antiviral therapies. Management is purely supportive, and mostly based around maintaining fluid balance. Paracetamol is used for fever and pain control. Aspirin and Ibuprofen are not preferred because they may cause further bleeding. Severe hospitalized cases may need a blood transfusion.
The virus has four different serotypes. Infection with one type gives immunity against that type but increases the likelihood of DHF if the individual subsequently contracts one of the other strains. Ninety-five per cent of severe/hospitalized cases of Dengue are associated with second infection. Because of this, developing a vaccine has proved complicated. The FDA approved Dengvaxia is only approved for the vaccination of children aged nine to 16 years old, who have been laboratory confirmed with previous Dengue, and who live in an endemic area.
For the rest of us, it is about avoidance, with the use of mosquito nets and Deet-based mosquito repellants. Don’t forget to clean those swimming pools!
Dr Julian Martin Chadwick - Internal Medicine Physician
Columbia Asia Hospital - Saigon