Dengue is a viral infection transmitted by mosquitoes and prevalent in hot, tropical regions. It results from any of the four closely related dengue virus serotypes, which cause a range of symptoms from mild (barely noticeable) to severe and requiring medical care and hospitalization. Fatalities can occur in severe cases. While there is no cure for the infection, the patient’s symptoms can be controlled.

At the beginning of this year, the WHO included dengue on its list of ten potential disease threats for 2019, and ongoing outbreaks in many countries support this assessment. Dengue outbreaks typically follow seasonal patterns, with transmission rates peaking during and after rainy periods. Several factors contribute to this rise, including high mosquito population levels, vulnerability to circulating dengue virus serotypes, favorable weather conditions such as temperature, precipitation, and humidity that impact the reproduction and feeding behavior of mosquitoes, and the incubation period of the dengue virus. Additional challenges include a lack of proactive control measures and limited staffing.

Symptoms

Dengue is a febrile illness that typically resolves on its own, and symptoms can range from no apparent signs to severe manifestations. Symptoms typically emerge between 4 to 10 days after being bitten by an infected mosquito. Dengue symptoms resemble those of the flu, and patients commonly experience:

  • fever 
  • headaches 
  • pain behind the eyes 
  • muscle and joint pain 
  • nausea/vomiting 
  • rash 
  • fatigue. 

In addition to flu-like symptoms, dengue patients may experience respiratory distress, nose and gum bleeding, and sudden drops in blood pressure leading to shock as the disease progresses. Without proper management, this can result in death. Fortunately, effective management of dengue cases in hospitals has significantly reduced the mortality rate to under 1% in most affected countries.

Over the course of 13 years (2000-2013), dengue has experienced a four-fold increase, surpassing any other communicable disease. Each year, it is estimated that approximately 100 million cases of symptomatic dengue occur, with an additional 300 million asymptomatic infections.

Treatment

Currently, there are no vaccines or antiviral treatments available specifically for dengue fever. Instead, paracetamol is recommended to manage fever, while aspirin and non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen should be avoided.

Recovering from an infection caused by one serotype of the dengue virus provides lifelong immunity against that particular serotype. However, this immunity only provides partial and temporary protection against subsequent infections by the other three serotypes of the virus. Studies indicate that getting infected with dengue virus sequentially increases the risk of developing severe dengue. The risk may also depend on the time elapsed between infections and the order of viral exposure.

The most effective approach to prevent dengue infection is to avoid mosquito bites, especially during the daytime when dengue-transmitting mosquitoes are active. These mosquitoes are commonly found in and around homes and gardens. To minimize the risk of mosquito bites, people should:

  • Wear clothing that adequately covers their body, especially their feet and legs.
  • Use insect screens over windows and doors to prevent mosquitoes from entering the house.
  • Apply insect repellents according to the manufacturer’s instructions.
  • Sleep under a mosquito net, even during the day.
  • Take extra care to avoid mosquito bites if a family member is already infected with dengue.