Dengue (pronounced DENgee) fever is a painful, debilitating mosquito-borne disease caused by any one of four closely related dengue viruses. These viruses are related to the viruses that cause West Nile infection and yellow fever. An estimated 400 million dengue infections occur worldwide each year, with about 96 million resulting in illness.

Dengue (break-bone fever) is a viral infection that spreads from mosquitoes to people. It is more common in tropical and subtropical climates. Most people who get dengue won’t have symptoms. But for those that do, the most common symptoms are high fever, headache, body aches, nausea and rash. Most will also get better in 1–2 weeks. Some people develop severe dengue and need care in a hospital. In severe cases, dengue can be fatal. You can lower your risk of dengue by avoiding mosquito bites especially during the day. Dengue is treated with pain medicine as there is no specific treatment currently.

Most people with dengue have mild or no symptoms and will get better in 1–2 weeks. Rarely, dengue can be severe and lead to death. Individuals who are infected for the second time are at greater risk of severe dengue. If symptoms occur, they usually begin 4–10 days after infection and last for 2–7 days. Symptoms may include:

• high fever (40°C/104°F)
• severe headache
• pain behind the eyes
• muscle and joint pain
• nausea
• vomiting
• swollen glands

Severe dengue symptoms often come after the fever has gone away:

• severe abdominal pain
• persistent vomiting
• rapid breathing
• bleeding gums or nose
• fatigue
• restlessness
• blood in vomit or stool
• being very thirsty
• pale and cold skin
• feeling weak.

People with these severe symptoms should get care right away.  After recovery, people who have had dengue may feel tired for several weeks.

Most cases of dengue fever can be treated at home with pain medicine. Preventing mosquito bites is the best way to avoid getting dengue. There is no specific treatment for dengue. The focus is on treating pain symptoms. Acetaminophen (paracetamol) is often used to control pain. Non-steroidal anti-inflammatory drugs like ibuprofen and aspirin are avoided as they can increase the risk of bleeding. There is a vaccine called Dengvaxia for people who have had dengue at least once and live in places where the disease is common. For people with severe dengue, hospitalization is often needed.

Previous infection with DENV increases the risk of the individual developing severe dengue. Urbanization (especially unplanned), is associated with dengue transmission through multiple social and environmental factors: population density, human mobility, access to reliable water source, water storage practice etc. Community’s risks to dengue also depend on population’s knowledge, attitude and practice towards dengue, as well as the implementation of routine sustainable vector control activities in the community. Consequently, disease risks may change and shift with climate change in tropical and subtropical areas, and vectors might adapt to new environment and climate.

The mosquitoes that spread dengue are active during the day. Lower the risk of getting dengue by protecting yourself from mosquito bites by using:

• clothes that cover as much of your body as possible
• mosquito nets if sleeping during the day, ideally nets sprayed with insect repellent
• window screens
• mosquito repellents (containing DEET, Picaridin or IR3535)
• coils and vaporizers.

If you get dengue, it’s important to:

• rest
• drink plenty of liquids
• use acetaminophen (paracetamol) for pain
• avoid non-steroidal anti-inflammatory drugs, like ibuprofen and aspirin
• watch for severe symptoms and contact your doctor as soon as possible if you notice any.

So far one vaccine (Dengvaxia) has been approved and licensed in some countries. However, only persons with evidence of past dengue infection can be protected by this vaccine. Several additional dengue vaccine candidates are under evaluation.

Besides the dengue fever, we will also have to be concern with seasonal influenza. Seasonal influenza is an acute respiratory infection caused by influenza viruses which circulate in all parts of the world. It represents a year-round disease burden. It causes illnesses that range in severity and sometimes lead to hospitalization and death. Most people recover from fever and other symptoms within a week without requiring medical attention. However, influenza can cause severe illness or death, particularly among high risk groups including the very young, the elderly, pregnant women, health workers and those with serious medical conditions. In temperate climates, seasonal epidemics occur mainly during winter, while in tropical regions, influenza may occur throughout the year, causing outbreaks more irregularly.

Seasonal influenza is characterized by a sudden onset of fever, cough (usually dry), headache, muscle and joint pain, severe malaise (feeling unwell), sore throat and a runny nose. The cough can be severe and can last two or more weeks.

Most people who get flu will recover in a few days to less than two weeks, but some people will develop complications (such as pneumonia) as a result of flu, some of which can be life-threatening and result in death. Sinus and ear infections are examples of moderate complications from flu, while pneumonia is a serious flu complication that can result from either flu virus infection alone or from co-infection of flu virus and bacteria. Other possible serious complications triggered by flu can include inflammation of the heart (myocarditis), brain (encephalitis) or muscle tissues (myositis, rhabdomyolysis), and multi-organ failure (for example, respiratory and kidney failure). Flu virus infection of the respiratory tract can trigger an extreme inflammatory response in the body and can lead to sepsis, the body’s life-threatening response to infection. Flu also can make chronic medical problems worse. For example, people with asthma may experience asthma attacks while they have flu, and people with chronic heart disease may experience a worsening of this condition triggered by flu.

Most people will recover from influenza on their own. People with severe symptoms or other medical conditions should seek medical care. People with mild symptoms should:

• stay home to avoid infecting other people
• rest
• drink plenty of fluids
• treat other symptoms such as fever
• seek medical care if symptoms get worse.

People at high risk or with severe symptoms should be treated with antiviral medications as soon as possible. They include people who are:

• pregnant
• children under 59 months of age
• aged 65 years and older
• living with other chronic illnesses
• receiving chemotherapy
• living with suppressed immune systems due to HIV or other conditions.

The WHO Global Influenza Surveillance and Response System (GISRS) monitors resistance to antivirals among circulating influenza viruses to provide timely evidence for national policies related to antiviral use.

To help control the spread of influenza in your community, stay home and keep sick children home until the fever has been gone, without the use of medicine, for 24 hours. Unless you’re going to a medical appointment, avoid being around other people until you’re feeling better. If you do need to leave your home to get medical care, wear a face mask. Wash your hands often.