Dengue (break-bone fever) is a mosquito-borne viral infection that poses a significant public health threat in many parts of the world. It is a common illness in tropical and subtropical regions worldwide, with an estimated 100-400 million infections occurring annually. It is caused by the dengue virus, which is transmitted to humans mainly through the bites of infected female mosquitoes of the Aedes species. 

Symptoms

Dengue symptoms typically appear 4-10 days after an infected mosquito bite and can range from mild to severe. In mild cases, symptoms may include:

• High fever (40°C/104°F)

• Headache

• Muscle and joint aches

• Nausea and vomiting

• Rash

• Pain behind the eyes

• Swollen glands

In some cases, dengue can progress to severe dengue, which is a life-threatening condition. Signs and symptoms of severe dengue may include:

• Severe abdominal pain

• Persistent vomiting

• Bleeding from gums/nose

• Bloody vomit or stool

• Bruising (bleeding under the skin)

• Drowsiness or restlessness

• Cold, pale skin

• Fatigue

• Difficult or rapid breathing

• Irritability or restlessness

Diagnosis

Diagnosing dengue fever involves a combination of:

• Clinical assessment

• Laboratory tests

Clinical Assessment

• Symptom evaluation: The patient's symptoms, including the sudden onset of fever, severe headaches, and joint/muscle pain are considered.

• Travel history: A travel history to dengue-endemic areas is critical in suspecting the diagnosis.

Laboratory Tests

1. Blood tests: Dengue virus-specific tests, such as the reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), are used to detect the presence of the virus or antibodies in the blood.

2. Hematological tests: Platelet and hematocrit levels are typically evaluated during the early phases of dengue infection. Alterations in blood cell counts, including a reduction in platelet count (thrombocytopenia), serve as markers for the presence of dengue infection.

3. Nucleic acid amplification tests (NAATs): For individuals suspected of  dengue virus disease, NAATs are the preferred diagnostic method. It is recommended to conduct NAATs on serum samples obtained within the first 7 days of the onset of symptoms.

4. Serologic tests:

• IgM antibody testing: It serves as a valuable diagnostic tool for identifying additional infections, particularly in the context of the dengue virus. The presence of IgM in a single serum sample strongly indicates a recent dengue virus infection.

• IgG antibody testing: It is used to detect recent or past dengue infections.

• IgM/IgG ratio: It is used to differentiate primary and secondary dengue virus infections.

• IgA: IgA can be detected in the blood using a test called anti-dengue virus IgA capture ELISA. While IgM antibodies typically become detectable a day earlier, IgA antibodies peak around 8 days after the onset of fever and disappear much faster, becoming undetectable by day 40.

5. Cross-reactive flaviviruses: In regions where other potentially cross-reactive flaviviruses like Zika, yellow fever, and West Nile virus are common, both molecular and serologic testing should be performed for dengue and other flaviviruses to confirm the diagnosis.

6. Hemagglutination-inhibition (HI) test: The HI test is used to detect antibodies against dengue virus. It relies on the hemagglutination property of dengue antigens.

Treatment

Currently, there is no precise antiviral treatment for dengue fever. Management focuses on relieving symptoms, preventing complications, and supportive care. Key aspects of dengue management include:

Fluid Replacement

• Oral rehydration: Mild cases may be managed with oral rehydration solutions to prevent dehydration.

• Intravenous fluids: Severe cases, especially those with dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS), may require intravenous fluids to maintain adequate blood volume and prevent shock.

Pain Relief

• Analgesics: Pain relievers such as acetaminophen are recommended to alleviate fever and joint/muscle pain. However, non-steroidal anti-inflammatory drugs (NSAIDs) and aspirin should be avoided.

Monitoring and Hospitalization

• Close monitoring: Patients with severe symptoms, signs of dehydration, or those at risk of complications are closely monitored in a hospital setting.

• Blood pressure management: For cases of DSS, careful management of blood pressure is crucial to prevent organ failure.

Prevention of Mosquito Bites

• Efforts to control mosquito populations, including the elimination of breeding sites and the use of insecticides, are essential in preventing the spread of dengue.

• Individuals in endemic areas are advised to use mosquito repellents, wear long sleeves and pants, and use bed nets to minimize exposure to mosquitoes.

Dengue fever remains a global health threat. While most cases are mild, the risk of severe complications demands early diagnosis and proper management. Preventing and mitigating dengue outbreaks requires robust public health initiatives, including mosquito control, community education, and effective surveillance.