Understanding Dengue fever: Transmission, symptoms, and life-threatening complications

Dengue fever, a mosquito-borne viral infection, continues to be a major public health concern in tropical and subtropical regions worldwide. This disease, transmitted primarily by the Aedes aegypti mosquito, poses a significant risk due to its rapid spread and potentially life-threatening complications. With rising global temperatures and increasing urbanisation, the conditions favourable for dengue transmission are expanding, making awareness and early intervention critical.

How Dengue Fever Spreads: The Role of Aedes aegypti Mosquitoes

Dengue fever is caused by the dengue virus, which is transmitted to humans through the bite of an infected Aedes aegypti mosquito. Unlike most mosquitoes that bite during the night, Aedes aegypti is most active during daylight hours, particularly in the early morning and late afternoon. These mosquitoes thrive in urban environments, breeding in stagnant water found in containers like buckets, discarded tires, flowerpots, and water storage tanks.

The transmission of dengue fever occurs when a mosquito bites a person already infected with the virus, then bites another individual, spreading the infection. This cycle makes densely populated areas with poor sanitation especially vulnerable to outbreaks. To prevent dengue fever transmission, individuals are advised to eliminate standing water around their homes, use insect repellents, wear protective clothing, and install mosquito nets or screens to reduce exposure to mosquito bites.

The Impact of Dengue on Blood Platelets: Why It’s a Cause for Concern

One of the most dangerous effects of dengue fever is its ability to significantly reduce blood platelet counts, a condition known as thrombocytopenia. Platelets are essential components of the blood that aid in clotting, helping to prevent excessive bleeding when injuries occur. A healthy person typically has a platelet count ranging from 150,000 to 450,000 per microlitre of blood.

In dengue patients, the virus suppresses the bone marrow’s ability to produce platelets while simultaneously increasing the destruction of existing platelets. This sharp decline can lead to severe complications, including internal bleeding, organ damage, and even death if not managed promptly. Symptoms associated with low platelet counts include unexplained bruising, bleeding from the gums or nose, and the appearance of small red spots on the skin known as petechiae.

Medical professionals emphasise that monitoring platelet levels is critical in dengue management. A sudden drop in platelet count can indicate the progression to severe forms of the disease, such as dengue hemorrhagic fever or dengue shock syndrome, both of which require immediate medical intervention.

Types of Dengue Fever: From Mild Symptoms to Life-Threatening Conditions

Dengue fever presents in different forms, each varying in severity. Understanding these variations is crucial for timely diagnosis and treatment:

Classic Dengue Fever

Classic dengue fever, also known as uncomplicated dengue, manifests with flu-like symptoms, including a sudden high fever (often reaching 102–103°F), severe headaches, joint and muscle pain, skin rashes, and fatigue. The fever typically follows a biphasic pattern, subsiding after a few days before returning briefly. While most cases resolve with supportive care—such as rest, hydration, and over-the-counter pain relievers—monitoring is important to detect any signs of complications.

Dengue Hemorrhagic Fever (DHF)

Dengue hemorrhagic fever is a more severe form characterised by increased vascular permeability, leading to internal bleeding, low platelet counts, and plasma leakage. Symptoms may include persistent vomiting, abdominal pain, bleeding under the skin, gum or nosebleeds, and extreme fatigue. Patients with DHF often experience dangerously low blood pressure, which can progress to shock if untreated. Medical supervision is mandatory, with treatment focusing on fluid management, platelet monitoring, and supportive care in a hospital setting.

Dengue Shock Syndrome (DSS)

Dengue shock syndrome represents the most critical stage of the disease. It occurs when severe plasma leakage causes a significant drop in blood pressure, leading to circulatory failure. Symptoms include cold, clammy skin, rapid pulse, difficulty breathing, confusion, and organ dysfunction. DSS requires immediate hospitalisation, with aggressive fluid resuscitation and intensive care to stabilise the patient. Delayed treatment can result in fatal outcomes, making early recognition and intervention vital.

Diagnosing Dengue Fever: Tests That Confirm the Infection

Accurate and timely diagnosis of dengue fever is essential for effective management, particularly in distinguishing it from other febrile illnesses. Several diagnostic tests are commonly used to confirm dengue infection and assess disease severity:

Hematocrit Test: This test measures the proportion of red blood cells in the blood. An elevated hematocrit level can indicate dehydration or internal bleeding, both of which are signs of severe dengue. Normal hematocrit values range from 35% to 42%, and deviations from this range warrant further investigation.

Hess Test (Tourniquet Test): Used to assess capillary fragility, the Hess test involves applying a blood pressure cuff to the arm for five minutes. The appearance of more than 20 petechial spots suggests increased capillary permeability, a hallmark of dengue hemorrhagic fever.

Dengue Antibody Test: This is a confirmatory diagnostic tool that detects specific antibodies produced in response to the dengue virus. The presence of these antibodies helps confirm the infection, especially in cases where clinical symptoms are ambiguous.

Prompt diagnosis allows healthcare providers to initiate appropriate treatment and monitor for warning signs of severe dengue, reducing the risk of complications.

When to Seek Immediate Medical Attention

Dengue fever can deteriorate rapidly, especially during the critical phase when the fever subsides, and complications may arise. Individuals should seek urgent medical care if they experience any of the following symptoms:

• Persistent vomiting or severe abdominal pain
• Bleeding from the nose, gums, or under the skin
• Difficulty breathing or chest pain
• Fatigue, restlessness, or sudden drowsiness
• Signs of dehydration, such as reduced urination or dry mouth

Early intervention can be life-saving, particularly in cases of dengue hemorrhagic fever and dengue shock syndrome.