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Overview

What Is Malaria?

Malaria is an illness caused by Plasmodium parasites that infect red blood cells. Infected female Anopheles mosquitoes can transmit the parasites when they bite a person. Malaria can affect people living in or traveling to areas where it occurs, and illness may range from mild to life-threatening.

Symptoms

Malaria Symptoms

Malaria symptoms may begin days or weeks after an infected mosquito bite. The timing varies with the parasite species, a person’s prior immunity, and whether antimalarial medicine was taken. Some people become seriously ill quickly, so symptoms after travel to a malaria-risk area should be assessed promptly.

  • Fever
  • Chills
  • Sweating
  • Headache
  • Muscle aches
  • Tiredness
  • Nausea
  • Vomiting
  • Diarrhea
  • Abdominal pain

Seek urgent care

Severe malaria can worsen quickly

Confusion, seizures, difficulty breathing, jaundice, dark urine, extreme weakness, or loss of consciousness may signal severe malaria. Seek emergency medical care immediately if any of these symptoms occur.

How It Spreads

How Malaria Spreads

When an infected female Anopheles mosquito bites a person, it can acquire Plasmodium parasites from the person’s blood. The parasites develop inside the mosquito and can later pass to another person through a bite. This mosquito-to-person cycle is the usual way malaria is transmitted.

RouteHow it occurs
Mosquito biteAn infected female Anopheles mosquito passes Plasmodium parasites to a person while feeding.
Contaminated bloodMalaria can rarely spread through infected blood, including through an unsafe transfusion.
Shared needlesA contaminated needle or syringe can transfer infected blood.
Organ transplantationA transplanted organ can rarely carry malaria parasites.
Pregnancy or childbirthAn infected parent may transmit malaria to a baby during pregnancy or childbirth.

Risk Factors

Malaria Risk Factors

  • Living in a malaria-endemic area increases the chance of repeated exposure to infected mosquitoes.
  • Traveling to a malaria-endemic area can cause infection, especially without destination-specific prevention.
  • Sleeping without a mosquito net or other protection increases nighttime exposure to mosquito bites.
  • Limited access to prevention or prompt treatment increases the risk of infection becoming severe.

Factors linked with severe malaria

  • Young children have a higher risk of severe illness, particularly where malaria is common.
  • Pregnant people have an increased risk of complications from malaria.
  • Older adults may be more vulnerable to severe disease.
  • Travelers without partial immunity can become seriously ill after infection.
  • People with weakened immunity may have a higher risk of severe malaria.
  • Infection with Plasmodium falciparum, a malaria parasite species, is more likely to cause life-threatening disease.

Complications

Malaria Complications

  • Severe anemia can develop when malaria parasites destroy red blood cells.
  • Cerebral malaria can affect the brain and cause confusion or reduced consciousness.
  • Seizures may occur with severe malaria, especially when the brain is affected.
  • Respiratory distress can make breathing difficult.
  • Kidney failure can occur when severe infection damages kidney function.
  • Liver problems may cause jaundice and other signs of impaired liver function.
  • Low blood sugar can develop during severe illness or treatment.
  • Shock can occur when circulation fails to deliver enough blood to the body’s organs.
  • Untreated or severe malaria can result in death.

Medical attention

Do not wait if malaria is possible

Fever after travel to a malaria-risk area requires prompt medical assessment, even if the illness seems mild. Severe malaria can develop quickly, particularly with Plasmodium falciparum infection.

Diagnosis

How Malaria Is Diagnosed

Clinicians consider a person’s symptoms and recent travel or residence history, then confirm malaria with blood tests. Testing may include thick and thin blood smears or rapid diagnostic tests. Further evaluation can show how severe the illness is and whether organs have been affected.

What testing can show

  • Blood testing can identify Plasmodium parasites in a blood sample.
  • A blood smear can help estimate the number of infected red blood cells.
  • Testing can distinguish species such as P. falciparum and P. vivax.
  • Additional blood tests can check for anemia or signs of organ problems.

Treatment & Management

Malaria Treatment and Management

Suspected or confirmed malaria requires prompt treatment directed by a clinician. The medicine depends on the parasite species, where the infection was acquired, local drug resistance, illness severity, and personal health factors. Do not self-treat with leftover or non-prescribed medicines.

UNCOMPLICATED MALARIA

Recommended oral antimalarial regimens are selected according to the parasite species, resistance patterns, and location where the infection was acquired.

SEVERE MALARIA

Severe malaria is an emergency that requires hospital care, often including intravenous treatment, supportive care, and close monitoring for organ complications.

RELAPSE PREVENTION

Some species, including P. vivax and P. ovale, can remain dormant in the liver and may require additional prescribed treatment to prevent relapse.

Prevention

Malaria Prevention

  • Use an insect repellent according to the product instructions.
  • Wear long sleeves and long pants to reduce exposed skin.
  • Stay in screened or air-conditioned rooms when possible.
  • Sleep under an insecticide-treated bed net in areas where malaria is present.
  • Reduce indoor mosquito exposure by keeping screens intact and limiting entry points.

Before travel, consult a healthcare professional about destination-specific preventive medicines, when to start and stop them, and possible contraindications. Continue mosquito protection during the trip and after returning, because symptoms may begin after travel.

Prevention options

Use more than one prevention strategy

Malaria vaccines may be recommended for certain children in areas with substantial transmission. Vaccination does not replace mosquito protection or other recommended preventive measures.

Outlook and Prognosis

Malaria Outlook and Prognosis

Most people who receive the correct malaria treatment promptly recover. However, untreated or severe malaria can progress rapidly to organ failure or death. Early evaluation is especially important after travel or residence in an area where malaria occurs.

  • Parasite species influence the speed and severity of illness.
  • A higher parasite level can increase the risk of complications.
  • The time from symptom onset to treatment affects the outlook.
  • Age can influence the risk of severe disease and recovery.
  • Pregnancy can increase the risk of complications.
  • Immune status affects how the body responds to infection.
  • Geographic drug resistance can limit treatment choices.
  • Complications involving the brain or other organs can worsen the prognosis.

When Should You See a Doctor

When Should You See a Doctor for Malaria?

Emergency symptoms

Seek emergency care now

Get emergency medical help for confusion, seizures, trouble breathing, fainting, severe weakness, jaundice, dark urine, or inability to keep fluids down.

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