Measles
Measles (also known as rubeola) is a highly contagious viral respiratory illness. It causes high fever and a distinctive red rash and can lead to serious complications, especially in young children and people with weakened immune systems.
If you or your child develops a high fever, cough, runny nose, red eyes, and a rash, seek medical care promptly.
(These images show the characteristic measles rash and early signs like red eyes or Koplik spots.)
Symptoms and Causes
Symptoms of measles
Symptoms usually appear 10–14 days after exposure. The illness often starts with flu-like symptoms (the “3 Cs”) followed by a rash. Common symptoms include:
- High fever (often over 104°F / 40°C)
- Cough
- Runny nose (coryza)
- Red, watery eyes (conjunctivitis)
- Tiny white spots inside the mouth (Koplik spots) — these appear 2–3 days before the rash
- Red, blotchy rash that starts on the face and spreads downward to the neck, trunk, arms, and legs
The rash usually lasts about a week. Early symptoms last 4–7 days before the rash appears.
Causes of measles
Measles is caused by the measles virus (a morbillivirus). Here’s how it spreads:
- The virus spreads through respiratory droplets from coughing or sneezing.
- It can remain in the air or on surfaces for up to 2 hours.
- One person with measles can infect up to 90% of unvaccinated close contacts.
- The virus infects the respiratory tract and then spreads throughout the body.
Risk factors
Children under 5, adults over 20, pregnant people, and those with weakened immune systems face higher risk of severe complications such as pneumonia, ear infections, diarrhea, encephalitis, or death.
Diagnosis and Tests
Doctors often diagnose measles based on symptoms and the appearance of the rash. Blood tests or swabs can confirm the presence of the virus and rule out similar illnesses.
Management and Treatment
There is no specific antiviral treatment for measles. Care focuses on supportive measures:
- Plenty of rest and fluids
- Fever reducers such as acetaminophen (paracetamol)
- Vitamin A supplements (recommended in some cases, especially for children in areas with deficiency)
- Hospital care for complications like pneumonia or severe dehydration
Outlook / Prognosis
Most people recover within 2–3 weeks, but complications can be serious or fatal, especially in young children or malnourished individuals. Vaccination provides strong, long-lasting protection.
Prevention
The MMR vaccine (measles-mumps-rubella) is the best prevention. Two doses provide about 97% protection. Children should receive the first dose at 12–15 months and the second at 4–6 years.
During outbreaks, unvaccinated people should avoid exposure and follow public health guidance.
Sources: Information adapted from World Health Organization (WHO) Measles Fact Sheet and U.S. Centers for Disease Control and Prevention (CDC) measles resources.
3. Heatstroke
Heatstroke is the most severe form of heat-related illness. It occurs when your body overheats and cannot cool itself, causing core body temperature to rise rapidly (usually above 104°F / 40°C). Heatstroke is a medical emergency that can damage the brain, heart, kidneys, and other organs.
If you or someone nearby shows signs of heatstroke, call emergency services immediately.
(These images illustrate common heatstroke symptoms and first-aid steps.)
Symptoms and Causes
Symptoms of heatstroke
Heatstroke symptoms develop quickly and require urgent action. Common signs include:
- Very high body temperature (104°F / 40°C or higher)
- Confusion, agitation, slurred speech, or altered mental state
- Dizziness, fainting, or loss of consciousness
- Hot, red, dry skin (may stop sweating in classic heatstroke) or heavy sweating (in exertional heatstroke)
- Rapid heartbeat and breathing
- Headache, nausea, or vomiting
- Seizures
Causes of heatstroke
Heatstroke happens when the body’s cooling mechanisms are overwhelmed. Key factors include:
- Prolonged exposure to high temperatures and humidity
- Strenuous physical activity in hot conditions (exertional heatstroke)
- Dehydration, which reduces the body’s ability to sweat and cool down
- Certain medications, alcohol use, obesity, or lack of air conditioning
- Poor acclimatization to hot environments
There are two main types: classic (non-exertional, common in older adults during heat waves) and exertional (during intense activity).
Risk factors
Higher risk groups include older adults, young children, people with chronic illnesses, outdoor workers, and athletes.
Diagnosis and Tests
Diagnosis is based on symptoms, measured body temperature, and recent heat exposure. In hospital settings, doctors may run tests to check for organ damage.
Management and Treatment
Heatstroke requires immediate emergency care. While waiting for help:
- Move the person to a cool, shaded area
- Remove excess clothing
- Cool the body rapidly with cold water, wet towels, ice packs (especially on neck, armpits, and groin), or fans
- Do not give fluids if the person is unconscious or confused
Hospital treatment includes IV fluids, continued cooling, and monitoring of vital organs.
Outlook / Prognosis
With prompt treatment, many people recover fully. However, delays can lead to permanent organ damage or death. Recovery time varies depending on severity and how quickly cooling begins.
Prevention
Prevent heatstroke by:
- Staying hydrated — drink plenty of water
- Avoiding strenuous activity during the hottest parts of the day
- Wearing lightweight, loose-fitting clothing and using sunscreen
- Never leaving children or pets in parked cars
- Using air conditioning or fans and taking breaks in cool areas
- Gradually acclimating to hot weather if working or exercising outdoors
Sources: Information adapted from World Health Organization (WHO) resources on heat and health and U.S. Centers for Disease Control and Prevention (CDC) heat-related illnesses guidance.
Dengue Fever
Dengue fever is an illness you can get when an infected mosquito bites you. Four types of dengue virus (DENV-1 to DENV-4) can cause it. The virus is most common in tropical and subtropical regions, including parts of Asia, Africa, Central and South America, and the Pacific Islands. Many people have mild or no symptoms, especially during their first infection. However, about 1 in 20 people can develop severe dengue, which can be life-threatening.
If you live in or are visiting an area where dengue is common (including many parts of Bangladesh), get immediate medical attention for signs of severe dengue.
(Aedes mosquitoes transmit the dengue virus. They bite during the daytime and breed in standing water)
Symptoms and Causes
Symptoms of dengue
Dengue infections can cause no symptoms, mild symptoms, or very severe symptoms. Initial symptoms usually start 4–10 days after a mosquito bite. Common symptoms include:
- High fever (up to 104°F / 40°C)
- Severe headache
- Pain behind the eyes
- Muscle, bone, and joint pain (often called “breakbone fever”)
- Nausea or vomiting
- Swollen lymph nodes
- Rash (may appear a few days after fever starts)
Symptoms of severe dengue usually begin a few hours to a few days after the initial fever starts to improve. Warning signs include:
- Severe belly (abdominal) pain
- Persistent or frequent vomiting
- Vomiting blood or blood in stool
- Bleeding from the nose or gums
- Easy bruising or bleeding under the skin
- Extreme tiredness, restlessness, or irritability
- Difficulty breathing or signs of shock
Causes of dengue
Dengue is caused by four closely related dengue viruses (DENV). Here’s how it happens:
- An Aedes mosquito (usually Aedes aegypti) bites a person who has dengue and becomes infected with the virus.
- The infected mosquito then bites another person and passes the virus through its saliva.
- Once inside the body, the virus enters the bloodstream and multiplies.
- In some cases (especially with a second infection from a different dengue virus type), the immune system’s response can cause blood vessels to leak and platelet counts to drop.
- This combination can lead to internal bleeding, low blood pressure, and organ damage — the dangerous features of severe dengue.
How does it spread?
Dengue spreads mainly through the bite of infected Aedes mosquitoes. These mosquitoes bite during the day and often live around homes in urban and suburban areas. Dengue is not contagious from person to person like the flu, though a pregnant person can rarely pass it to their baby during pregnancy or childbirth.
Risk factors
People at higher risk include:
- Those living in or traveling to tropical/subtropical areas where dengue is common
- Children and older adults (over 65)
- People who have had dengue before (second infections are more likely to be severe)
Diagnosis and Tests
Healthcare providers usually diagnose dengue based on your symptoms, recent travel or exposure history, and a blood test. The blood test can detect the virus or antibodies and sometimes identify which of the four dengue virus types is involved. Tests may also rule out other illnesses with similar symptoms.
Management and Treatment
There is no specific antiviral medicine that cures dengue. Treatment focuses on relieving symptoms and preventing complications.
For mild dengue, care at home usually includes:
- Plenty of rest
- Drinking lots of fluids (water, oral rehydration solutions) to stay hydrated
- Taking acetaminophen (such as paracetamol) for fever and pain
- Avoid aspirin, ibuprofen, or other NSAIDs — these can increase the risk of bleeding
If you develop warning signs of severe dengue, go to the hospital immediately. Severe cases may need:
- Close monitoring
- Intravenous (IV) fluids
- Blood transfusion (in rare cases)
Most people with mild dengue recover in 3–7 days with good supportive care.
Outlook / Prognosis
Most people recover fully from dengue fever without lasting problems, especially if treated early. Severe dengue can be life-threatening, but the risk of death drops dramatically with prompt hospital care.
You can get dengue more than once because there are four different virus types. A second infection with a different type often carries a higher risk of severe disease.
Prevention
The best way to prevent dengue is to avoid mosquito bites. Helpful steps include:
- Use insect repellent containing DEET, picaridin, or other EPA-registered ingredients
- Wear long-sleeved shirts and long pants, especially during the day
- Use screens on windows and doors; repair any holes
- Eliminate standing water around your home (in buckets, flowerpots, tires, etc.) where mosquitoes breed
- Sleep under a mosquito net if needed
- In areas with ongoing outbreaks, follow local public health advice
A dengue vaccine is available in some countries for people who have previously had dengue, but it is not recommended for everyone. Check with your doctor or local health authority for the latest guidance.