Understanding Dengue Hemorrhagic Fever: Causes, Symptoms, and Prevention

Introduction to Dengue Hemorrhagic Fever

Dengue Hemorrhagic Fever (DHF) is an acute and potentially lethal complication of dengue fever, a tropical disease caused by the dengue virus. Spread by the bite of infected Aedes mosquitoes, primarily Aedes aegypti, this disease is alarmingly prevalent in over 100 countries, with about half of the world’s population at risk.

DHF is marked by the unique clinical features that differentiate it from common dengue fever. It causes high fever and the typical flu-like symptoms seen in dengue and leads to severe bleeding, blood plasma leakage, and low platelet count. This condition can be so severe that it can lead to shock, organ failure, and even death if not managed appropriately.

Moreover, DHF occurs when a person is infected with the dengue virus for the second time. This is because the immune response from the first infection increases the risk of developing DHF upon re-infection, a phenomenon known as antibody-dependent enhancement.

The increasing spread of the dengue virus worldwide and the high fatality rate of DHF make this disease a significant global health concern. This necessitates a deep understanding of the condition, its diagnosis, treatment, and preventive measures to effectively control its spread and impact.

What Causes Dengue Hemorrhagic Fever?

The primary cause of Dengue Hemorrhagic Fever (DHF) is infection by one of the four dengue virus serotypes (DEN-1, DEN-2, DEN-3, and DEN-4). These viruses are members of the Flavivirus genus. They are transmitted to humans through the bite of an infected female Aedes mosquito, primarily Aedes aegypti and, to a lesser extent, Aedes albopictus.

Let’s dive a little deeper into the science behind the cause. Once a dengue virus enters the human body, it takes refuge in the white blood cells and replicates while the cells perform their normal functions. The virus is then released when the infected cells die, spreading to other white blood cells and throughout the bloodstream.

Interestingly, it’s not the first infection with the dengue virus that usually causes DHF but rather a subsequent infection with a different dengue serotype. This happens due to a phenomenon called antibody-dependent enhancement (ADE). In ADE, antibodies from a first dengue infection fail to neutralize a second dengue virus of a different serotype during re-infection. Instead, they aid the virus entering host cells, enhancing its reproduction ability and leading to severe disease.

Why does this happen? The primary response of our immune system to an infection is to produce specific antibodies that can neutralize the invading pathogen. When a person is infected with the dengue virus for the first time, the immune system responds by producing antibodies specific to that serotype. These antibodies will neutralize the virus and aid in its clearance, thus resolving the infection.

However, problems arise when the person is later infected with a different dengue serotype. The antibodies from the first infection can’t neutralize the new serotype effectively. Instead, they form complexes with the virus that are more readily taken up by cells involved in the immune response. This leads to increased viral replication, a higher viral load, and a much more severe disease, resulting in DHF or even more severe dengue shock syndrome (DSS).

DHF and DSS are also influenced by various other factors, such as the strain and serotype of the dengue virus, age, genetic predisposition, and the individual’s immune status. For instance, infants born to dengue-immune mothers are at a higher risk of severe disease due to the presence of maternal antibodies, which can enhance viral infection.

The primary vector, the Aedes aegypti mosquito, is a day-biting species that prefers feeding on humans. It breeds clean, stagnant water in various domestic and peridomestic settings, including water storage containers, used automobile tires, flower vases, and discarded containers. These mosquitoes are highly adaptive to the human environment, coupled with increasing urbanization and inadequate vector control, which has led to a surge in dengue transmission in urban and semi-urban settings.

To sum up, the cause of DHF is multi-factorial, involving not only the dengue virus and its serotypes but also the human immune response, the vector mosquito species, and various ecological factors. Understanding this complex interplay is crucial for devising effective strategies for preventing and controlling DHF.

The Aedes Mosquito: Dengue’s Culprit

The Aedes mosquito, mainly Aedes aegypti and, to a lesser extent, Aedes albopictus, plays a crucial role in transmitting the dengue virus, which causes Dengue Hemorrhagic Fever. Aedes aegypti, the yellow fever mosquito, is the primary vector that spreads the virus amongst humans. This mosquito has become a significant threat to public health worldwide due to its adaptability to urban environments and daytime feeding habits.

Aedes aegypti mosquitoes thrive near humans, often breeding in artificial water containers such as flower pots, discarded tires, buckets, and anything that can hold stagnant water. They prefer clean water and can lay their eggs in as little as an inch of standing water. The larvae become adult mosquitoes within approximately one week, ready to perpetuate the dengue transmission cycle.

These mosquitoes are distinguished by their marked white bands on the legs and a characteristic lyre-shaped pattern of white markings on the thorax. But their distinctive appearance isn’t what makes them a public health menace. It’s their feeding habits and their role in virus transmission.

Aedes mosquitoes are primarily daytime feeders, with peaks in activity in the early morning and late afternoon. This behaviour is particularly problematic as it coincides with human activity, increasing the chances of human-mosquito contact and dengue transmission. When an Aedes mosquito bites a person infected with the dengue virus, the mosquito becomes infected with the virus. When the infected mosquito bites another person, the virus is transmitted, causing the disease in the newly infected person.

The geographical distribution of Aedes aegypti and Aedes albopictus has increased over the last few decades due to urbanization, global travel, climate change, and lack of effective mosquito control, leading to an alarming rise in dengue cases worldwide. Effective mosquito control strategies are integral to the global fight against Dengue Hemorrhagic Fever and other diseases transmitted by these vectors.

The Manifestation of Dengue Hemorrhagic Fever

Dengue Hemorrhagic Fever typically develops after an incubation period of 4 to 10 days following a mosquito bite.

The Four Stages of Dengue Hemorrhagic Fever

The illness can be divided into three stages: the Febrile stage, the Critical stage, and the Recovery stage.

Febrile Stage

The febrile stage is the initial phase of Dengue Hemorrhagic Fever (DHF) and typically lasts 2 to 7 days. This phase sets in abruptly and is characterized by high fever and other systemic symptoms.

The first symptom in the febrile stage is usually a sudden, high fever, often as high as 104°F (40°C). This fever is typically biphasic or “saddleback” in nature, meaning it will persist for a few days, then briefly diminish, only to return for one or two more days. When the fever subsides, the patient may experience a temporary respite from other symptoms, which is usually short-lived.

Along with high fever, the febrile stage also presents with several other symptoms, including severe headaches, retro-orbital pain (pain behind the eyes), muscle and joint pain, and sometimes, a maculopapular or petechial rash, which usually appears on the torso first and then spreads to the face, arms, and legs. The severe muscle and joint pains have given dengue the moniker “breakbone fever” or “dandy fever.” Nausea, vomiting, and loss of appetite are also commonly reported during this phase.

In addition to these symptoms, patients might display clinical signs such as flushing, facial redness, or skin erythema. Flushing or redness of the face is often apparent during the first few days of fever. In some patients, the disease can also affect the lymph nodes, leading to generalized lymphadenopathy (swelling of the lymph nodes).

It’s important to note that the febrile phase symptoms of DHF are very similar to those of classic dengue fever and other febrile illnesses. This makes early diagnosis difficult and often leads to misdiagnosis. Medical professionals must carefully evaluate the patient’s history, particularly any recent travel to dengue-endemic regions or contact with infected individuals.

During the febrile stage, the dengue virus is present at high levels in the blood, and the patient is highly infectious to mosquitoes. If an Aedes mosquito bites the patient during this period, it becomes infected with the dengue virus and can spread it to other individuals when it takes its next blood meal.

While the febrile stage is rarely life-threatening, managing symptoms effectively is essential. Proper hydration, rest, and over-the-counter pain relievers can help manage fever and body aches. However, healthcare providers usually recommend avoiding medicines with aspirin or ibuprofen, as they can increase the risk of bleeding.

Additionally, monitoring for any warning signs of progression to severe dengue, such as persistent vomiting, severe abdominal pain, rapid breathing, bleeding gums, fatigue, or restlessness, is essential. If these symptoms appear, it is crucial to seek immediate medical attention.

Without specific antiviral therapy for dengue, early recognition and anticipatory guidance during the febrile phase are critical in preventing progression to severe disease. As the disease advances towards the critical phase, the risk of complications such as plasma leakage, severe bleeding, and organ impairment becomes high.

In summary, the febrile phase is the initial stage of Dengue Hemorrhagic Fever, marked by high fever, severe headaches, muscle and joint pain, and sometimes, a characteristic rash. This phase is essential for early diagnosis and symptomatic treatment initiation, helping prevent further complications.

Critical Stage

The critical stage, also known as the plasma leakage phase, is the second phase of Dengue Hemorrhagic Fever (DHF). It usually occurs around the third to seventh day of illness and lasts 24 to 48 hours. This phase marks a critical period of the disease where the patient may develop severe complications if not managed appropriately.

As the high fever from the febrile phase begins to subside, patients might experience a temporary improvement in their overall well-being. However, this brief respite is often misleading and may coincide with the onset of the critical stage. The patient’s condition may deteriorate rapidly during this stage, often within a few hours.

The hallmark of the critical stage is an increase in vascular permeability, leading to plasma leakage from the blood vessels into the surrounding tissues and body cavities. This results in a drop in plasma levels and leads to hemoconcentration, evidenced by a rise in hematocrit. The plasma leakage is believed to result from the immune response to the dengue virus, releasing immune mediators that increase vascular permeability.

Clinically, this manifests as symptoms of fluid accumulation in various parts of the body. This can include pleural effusion (fluid around the lungs), ascites (fluid in the abdominal cavity), and generalized oedema (swelling). If severe, this fluid loss from the circulation can lead to dengue shock syndrome, a life-threatening complication characterized by rapid and weak pulse, narrow pulse pressure, hypotension, and cold, clammy skin.

Another key characteristic of the critical phase is the manifestation of bleeding tendencies. Minor bleeding manifestations, such as petechiae (small, pinpoint haemorrhages), ecchymoses (more significant areas of bruising), gum bleeding, and nosebleeds, are common. However, more severe bleeding manifestations can also occur, particularly in those with prolonged shock, such as gastrointestinal bleeding, which can present as black, tarry stools (melena) or bloody vomit (hematemesis).

In the critical stage, monitoring for warning signs is essential. These can include persistent vomiting, severe abdominal pain, rapid breathing, fatigue, or restlessness. In addition, a sudden drop in temperature, or “defervescence,” from high fever to below 38°C (100.4°F) can also be a warning sign of the transition to the critical phase.

In this phase, immediate medical attention is required. Fluid replacement therapy forms the cornerstone of treatment to replace lost plasma and maintain adequate organ perfusion. This involves careful administration of intravenous fluids, keeping in mind that overhydration can worsen fluid leakage. Blood products may also be required if severe bleeding occurs. The goal is to support the patient through the critical stage until their physiology begins to normalize, marking the start of the recovery phase.

In conclusion, the critical phase of DHF is a period of increased vulnerability for the patient. It is characterized by plasma leakage and bleeding tendencies, leading to severe complications such as shock if not appropriately managed. A high index of suspicion, diligent monitoring, and timely intervention are crucial to navigate this critical stage and improve patient outcomes.

Recovery Stage

The recovery stage, the reabsorption or convalescent phase, is the final stage of Dengue Hemorrhagic Fever (DHF). This stage follows the critical phase and usually lasts 2 to 3 days. The transition to the recovery phase is typically marked by an improvement in the patient’s general well-being, appetite, and hemodynamic status.

The recovery stage is characterized by the gradual reabsorption of extravasated plasma back into the bloodstream. This process usually begins 48 to 72 hours after the onset of the critical phase. Clinically, this is evident by a sudden drop in hematocrit concurrent with a rapid improvement in the patient’s health status.

During this phase, it’s essential to monitor for signs of fluid overload, which can occur due to the sudden return of plasma to the circulation combined with fluid therapy. Signs of fluid overload can include dyspnea (difficulty breathing), peripheral oedema (swelling in the legs, ankles, and feet), and in severe cases, congestive heart failure. Fluid therapy should be carefully reduced as the patient’s condition improves to prevent this complication.

Patients usually show significant improvement during the recovery phase, with the disappearance of fever and alleviation of other symptoms. There is a return of appetite and an improvement in gastrointestinal symptoms such as nausea and vomiting. This is also when the rash commonly associated with dengue, which usually appears in the febrile stage, typically peels off, leaving the skin mottled.

Most patients recover without severe complications during this phase. However, it’s important to remember that the body has undergone significant stress during the illness, and full recovery may take a few weeks. It’s common for patients to experience post-dengue fatigue syndrome, characterized by prolonged tiredness, sleep disturbances, and cognitive impairments such as poor concentration and memory loss. Adequate rest, nutrition, and symptomatic treatment, such as pain relievers for residual joint pain, can help manage these post-dengue symptoms.

In addition to physical recovery, psychological support might also be necessary for some patients. Experiencing a severe illness like DHF can be traumatic, and some patients may exhibit signs of anxiety or depression post-illness. Mental health support, including counselling if needed, can aid recovery.

After recovery, the immune system typically produces lifelong immunity against the dengue serotype that caused the infection. However, this immunity does not extend to the other three serotypes; subsequent infections with a different serotype can still occur. Therefore, continued mosquito avoidance measures and monitoring for early signs of dengue in endemic areas remain crucial.

In conclusion, the recovery stage of DHF is a period of gradual improvement in symptoms and overall health status as the extravasated plasma is reabsorbed back into the bloodstream. Managing fluid therapy to prevent overload, ensuring adequate rest and nutrition, and providing psychological support are essential. Post-dengue symptoms may persist for a few weeks but usually, resolve with time and symptomatic treatment.

WHO classification of dengue infections and grading of severity of DHF

WHO classification of dengue infections and grading of severity of DHF
WHO classification of dengue infections and grading of severity of DHF

The Diagnosis and Treatment of Dengue Hemorrhagic Fever

Diagnosis of Dengue Hemorrhagic Fever can be challenging due to its nonspecific symptoms.

Diagnostic Methods

Diagnosing Dengue Hemorrhagic Fever (DHF) requires clinical assessment and laboratory testing. Early diagnosis is crucial for time management and prevention of severe complications. The diagnostic methods for dengue can be categorized into direct and indirect methods, each offering unique advantages and limitations.

Direct Methods

Direct methods involve the detection of the dengue virus, viral components, or products in the patient’s sample, typically blood.

  • Virus Isolation: This is the definitive method for dengue diagnosis, but it is complex, time-consuming, and requires high expertise and resources. The dengue virus can be isolated from blood samples during the febrile phase of the illness and grown in cell cultures. After incubation, the cultures are tested for the presence of the dengue virus.
  • Nucleic Acid Testing (NAT): This involves detecting the genetic material of the dengue virus. Reverse transcription-polymerase chain reaction (RT-PCR) is the most commonly used NAT. It can identify the dengue virus within the first five days of illness, particularly useful in early diagnosis. It also allows for serotyping, identifying the specific dengue virus serotype causing the infection.
  • Antigen Detection: This method involves identifying viral proteins. The NS1 antigen, a protein secreted by the dengue virus, can be detected from the first day of symptoms up to day 9 in primary infections and for a shorter period in secondary infections. NS1 antigen tests are relatively simple, rapid, and available as point-of-care tests, making them useful in resource-limited settings.

Indirect Methods

Indirect methods involve the detection of antibodies produced by the body’s immune response to the dengue virus.

  • Serology: Serological tests detect antibodies against the dengue virus. IgM antibodies typically become detectable 3-5 days after the onset of illness and remain in the bloodstream for up to 90 days. IgG antibodies appear later but persist for years, providing lifelong immunity against the specific serotype. A positive IgM test or a four-fold rise in IgG titers can confirm dengue infection. However, cross-reactivity with other flaviviruses can lead to false positives.
  • Plaque Reduction Neutralization Test (PRNT): PRNT is considered the gold standard for serological diagnosis. It measures the ability of the patient’s antibodies to neutralize the dengue virus. This test can also differentiate dengue from other flavivirus infections. However, PRNT is laborious, time-consuming, and requires specialized laboratory facilities.

Laboratory Parameters

Apart from these specific tests, certain laboratory findings can support the diagnosis of DHF, such as thrombocytopenia (low platelet count), leucopenia (low white blood cell count), and raised hematocrit, indicating hemoconcentration.

Overall, the selection of diagnostic tests depends on the phase of the illness, the resources available, and the need for specific information, such as serotyping. While laboratory confirmation is essential, clinical judgment remains crucial, especially in resource-limited settings where laboratory tests may not be readily available. It’s also worth noting that negative test results should not exclude dengue if the clinical suspicion is high.

H4: Treatment Strategies

Managing Dengue Hemorrhagic Fever (DHF) is primarily supportive as there is currently no specific antiviral treatment for dengue. The main objectives of treatment are to maintain the patient’s fluid balance, manage symptoms, and monitor for warning signs of severe disease.

Fluid Management

In the critical phase of DHF, characterized by increased vascular permeability and plasma leakage, fluid management forms the cornerstone of treatment. The goal is to replace the lost fluid volume and maintain adequate organ perfusion without causing fluid overload.

Oral rehydration is sufficient for patients with mild disease who can tolerate oral fluids. Oral rehydration solutions, such as those used to manage diarrhoea, can be used. They contain the right balance of salts and sugars to replace lost electrolytes and fluid.

For patients with moderate to severe disease or those unable to tolerate oral fluids, intravenous (IV) fluid therapy is necessary. Crystalloids are usually the first choice, like normal saline or Ringer’s lactate. The rate and volume of IV fluids are carefully adjusted based on the patient’s clinical response, vital signs, hematocrit levels, and urine output.

In cases of profound or persistent shock, colloids may be used. Colloids, such as hydroxyethyl starch or gelatins, have larger molecules that stay within the blood vessels longer, providing a better and longer-lasting increase in blood pressure.

Symptomatic Management

Symptomatic management aims to alleviate the discomfort associated with dengue symptoms.

  • Fever and Pain: Antipyretics like acetaminophen (paracetamol) manage fever and pain. Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), such as ibuprofen and aspirin, are generally avoided due to their potential to worsen bleeding tendencies and cause gastritis.
  • Nausea and Vomiting: Antiemetics can be administered to control nausea and vomiting.
  • Itching: Antihistamines can help manage the itching associated with the dengue rash.

Monitoring and Management of Complications

Close monitoring is essential for the timely detection and management of severe dengue complications, such as dengue shock syndrome and severe bleeding. This includes regular monitoring of vital signs, urine output, and hematocrit levels. Patients with severe complications may require admission to an intensive care unit for more intensive monitoring and care.

In cases of severe bleeding, a blood transfusion may be necessary. Platelet transfusion is usually reserved for patients with severe thrombocytopenia (meagre platelet count) and significant bleeding.

Post-Recovery Management

Even after recovering from the acute illness, some patients may experience post-dengue fatigue syndrome, characterized by prolonged tiredness, sleep disturbances, and cognitive impairments. Adequate rest, nutrition, and symptomatic treatment can help manage these post-dengue symptoms.

Psychological support may also be necessary for some patients who find the experience of a severe illness traumatic. This can include counselling or psychotherapy.

In conclusion, the management of DHF is mainly supportive, involving careful fluid management, symptomatic treatment, and vigilant monitoring for complications. Post-recovery care, including physical and psychological support, is essential to the overall treatment strategy.

Prevention of Dengue Hemorrhagic Fever

Prevention of Dengue Hemorrhagic Fever (DHF) primarily revolves around controlling the mosquito vectors and limiting human exposure. It’s especially crucial in endemic areas where the four dengue virus serotypes are prevalent.

Vector Control

Controlling the Aedes mosquito population, the primary vector for dengue, is a critical strategy for preventing DHF.

  • Source Reduction: This involves eliminating potential breeding sites for Aedes mosquitoes. These mosquitoes often breed in artificial containers that hold water, such as buckets, vases, and discarded tires. Regularly emptying and cleaning these containers can prevent mosquito breeding.
  • Chemical Control: Larvicides and adulticides can be used to control mosquito populations. Larvicides are applied to water bodies to kill mosquito larvae, while adulticides kill adult mosquitoes. It’s important to note that these chemicals should be used judiciously to prevent the development of resistance.
  • Biological Control: This involves using natural predators that eat mosquito larvae, such as certain fish and copepods. Another innovative method is the release of genetically modified mosquitoes or those infected with Wolbachia bacteria, which reduces their ability to transmit dengue.
  • Environmental Management: This encompasses broader efforts such as improving water storage practices, waste management, and urban planning to reduce mosquito breeding opportunities.

Personal Protection Measures

Personal protection measures aim to reduce mosquito bites, limiting dengue virus transmission.

  • Insect Repellents: Products containing DEET, picaridin, or oil of lemon eucalyptus have been found effective in repelling mosquitoes. These should be applied on exposed skin and can also be used on clothing.
  • Protective Clothing: Wearing long-sleeved shirts, long pants, socks, and shoes can minimize the exposed skin area that mosquitoes can bite.
  • Bed Nets and Screens: Using bed nets, preferably those treated with insecticides, can prevent mosquito bites during sleep. Installing screens on doors and windows can also help keep mosquitoes out of homes.

Dengue Vaccines

Dengue vaccines can also play a role in dengue prevention. As of my knowledge cutoff in September 2021, the only licensed dengue vaccine is Dengvaxia, developed by Sanofi Pasteur. This vaccine is recommended for individuals aged 9-45 years living in endemic areas and with confirmed previous dengue infection.

Dengvaxia is a live-attenuated vaccine that targets all four dengue virus serotypes. However, its efficacy varies by serotype and whether the individual has had a prior dengue infection. It’s important to note that the vaccine should not be given to individuals with prior dengue infection, as it can increase the risk of severe dengue in these individuals.

Several other dengue vaccines are under development and in various stages of clinical trials. It’s anticipated that the availability of more effective and safer dengue vaccines will significantly aid in global dengue prevention efforts.

In conclusion, prevention of DHF involves a multi-pronged approach that includes vector control, personal protection measures, and vaccination. Each of these strategies has its strengths and limitations, and their success largely depends on their proper implementation and the active participation of the community.

Future Outlook

Dengue Hemorrhagic Fever (DHF) continues to pose a significant public health challenge worldwide, with an estimated 390 million dengue infections occurring annually. However, advancements in research and technology provide a promising future outlook in the battle against this disease.

Improved Diagnostic Tools

Early and accurate diagnosis is critical for effective DHF management and preventing severe outcomes. The future promises more sophisticated and accessible diagnostic tools. There are ongoing efforts to develop rapid diagnostic tests that can be used at the point of care, even in resource-limited settings. Furthermore, advances in genomics and proteomics could lead to the discovery of novel biomarkers for dengue, improving diagnostic accuracy and providing insights into disease severity.

Advances in Treatment

While no specific antiviral treatment for dengue is currently available, several potential therapies are under investigation. These include antiviral drugs that target various stages of the dengue virus life cycle, immunotherapies to modulate the host’s immune response, and strategies to manage dengue-induced vascular leakage. The development and approval of a specific, effective treatment for dengue would be a significant breakthrough.

Next-Generation Vaccines

The availability of a safe and effective dengue vaccine would be a game-changer in dengue prevention. Although the currently available vaccine, Dengvaxia, has limitations, it represents a significant first step. Several next-generation dengue vaccines are in the pipeline, including live-attenuated, inactivated, DNA, and subunit vaccines. These candidates aim to provide balanced protection against all four dengue serotypes, even in dengue-naïve individuals, and to minimize the risk of antibody-dependent enhancement (ADE), a phenomenon believed to contribute to severe dengue.

Innovative Vector Control Strategies

Emerging technologies offer innovative strategies for dengue vector control. These include genetically modified mosquitoes, where male mosquitoes are engineered to produce offspring that do not survive to adulthood, thus reducing the mosquito population. Another approach involves infecting mosquitoes with Wolbachia, a naturally occurring bacterium that reduces the mosquitoes’ ability to transmit dengue.

Climate Change and Dengue

The future outlook on dengue also needs to consider the impact of climate change. Rising global temperatures and changes in rainfall patterns can influence the distribution and behaviour of Aedes mosquitoes, potentially leading to the spread of dengue to new regions. Therefore, climate change adaptation and mitigation strategies must be integrated into dengue control efforts.

In conclusion, while DHF remains a significant global health problem, the future brings hope through advanced diagnostic tools, novel treatments, next-generation vaccines, and innovative vector control strategies. However, the global community must also be prepared to address new challenges like climate change.

Frequently Asked Questions

  1. What is Dengue Hemorrhagic Fever (DHF)? Dengue Hemorrhagic Fever (DHF) is a severe form of dengue fever characterized by high fever, damage to lymph and blood vessels, bleeding from the nose and gums, liver enlargement, and circulatory system failure.
  2. How does DHF spread? DHF spreads through the bite of a female Aedes mosquito infected with one of the four dengue virus serotypes. Humans are the primary host of the virus.
  3. What are the symptoms of DHF? Symptoms of DHF typically begin with a high fever, severe headache, joint and muscle pain, and rash. As the disease progresses, symptoms may include severe abdominal pain, persistent vomiting, rapid breathing, bleeding gums, fatigue, restlessness, and blood in vomit.
  4. Can DHF be fatal? Yes, if not treated promptly, DHF can progress to severe stages that can be life-threatening.
  5. Who is at risk of DHF? Everyone is susceptible to the dengue virus. However, individuals who have a weak immune system or have had a dengue infection in the past are at higher risk of developing DHF.
  6. How is DHF diagnosed? DHF is diagnosed through a series of blood tests to check for the presence of the dengue virus or antibodies.
  7. How is DHF treated? Currently, there is no specific medication to treat DHF. The treatment focuses on maintaining the patient’s body fluid volume. In severe cases, hospitalization may be required.
  8. Can DHF be prevented? The most effective way to prevent DHF is to protect yourself from mosquito bites and control mosquito breeding sites.
  9. Is there a vaccine for dengue? As of my knowledge cutoff in September 2021, the Dengvaxia vaccine is available in specific populations in dengue-endemic areas but is not universally recommended.
  10. Can you get DHF more than once? Yes, there are four different types of dengue virus. You can potentially get infected with each one.
  11. Why is dengue often worse the second time? This is due to antibody-dependent enhancement (ADE), where antibodies from a previous infection bind to the new type of dengue virus and inadvertently help it infect more cells.
  12. What is dengue shock syndrome? Dengue shock syndrome is a severe form of dengue characterized by a sudden drop in blood pressure leading to shock. It can be life-threatening.
  13. What’s the difference between dengue fever and DHF? While the dengue virus causes both, DHF is a more severe form characterized by bleeding, blood plasma leakage, and low platelet count.
  14. How long does DHF last? The duration of DHF varies but is usually one to two weeks. Severe complications can extend this period.
  15. How can I protect myself from dengue while travelling? Using mosquito repellents, wearing long-sleeved clothing, and sleeping under mosquito nets can reduce the risk of mosquito bites. Also, avoid areas with known dengue outbreaks.
  16. Can DHF cause long-term complications? Most people recover fully from DHF, but in some cases, it can lead to prolonged fatigue and depression.
  17. Can DHF affect pregnancy? Pregnant women with DHF have a higher risk of miscarriage, premature birth, and low birth weight babies.
  18. What are some natural ways to prevent dengue? Natural prevention strategies include removing standing water (breeding grounds for mosquitoes), using natural mosquito repellents, and keeping the surroundings clean.
  19. Can I get dengue from another person directly? No, dengue does not spread directly from person to person. It requires a mosquito as a vector.


  1. World Health Organization – Dengue and severe dengue
  2. Centres for Disease Control and Prevention – Dengue
  3. Mayo Clinic – Dengue fever
  4. National Institute of Allergy and Infectious Diseases – Dengue Fever
  5. MedlinePlus – Dengue

My Other Articles:

Disclaimer: This article is intended for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always seek the advice of your physician or other qualified health providers with any questions you may have regarding your health. Never disregard professional medical advice or delay seeking it because of something you have read on this website.

Frequently Asked Questions

Reference List


All Tags

Related Posts

Follow Me

Tanzir Islam Britto

Hello, I'm Dr. Tanzir Islam Britto. As a dedicated physician, I've embarked on my medical journey at Bangabandhu Sheikh Mujib Medical College (BSMMC), previously known as Faridpur Medical College, where I pursued my Bachelor of Medicine and Bachelor of Surgery (MBBS). I completed my degree at Shahabuddin Medical College (SMC). Alongside my medical career, I am an amateur writer and an active social media advocate, where I share insights into health, wellness, and more.

Other Posts:

Social media can be a good thing. It can help you to connect with people, find like-minded communities, view content...

Researchers have unveiled groundbreaking insights into “super-agers,” elderly individuals whose cognitive abilities match those of much younger people. This research,...

Multitasking is often seen as the key to efficiency. But how many of these popular beliefs are myths? Discover the...
Scroll to Top