Malaria is a disease caused by a parasite. The parasite is transmitted to humans through the bites of infected mosquitoes. People who have malaria usually feel very sick with a high fever and chills. Although the disease is rare in temperate climates, malaria remains common in tropical and subtropical countries. Every year, almost 290 million people become infected with malaria and more than 400,000 people die from the disease.
To reduce malaria infections, global health programs distribute preventive medicines and insecticide-treated nets to protect people from mosquito bites. The World Health Organization has recommended a malaria vaccine for use in children living in countries with a high number of malaria cases.
Protective clothing, mosquito nets, and insecticides can protect you while you travel. You can also take preventive medicine before, during, and after a trip to a high-risk area. Many malaria parasites have developed resistance to the common drugs used to treat the disease.
Malaria signs and symptoms may include:
- Shaking chills
- General feeling of discomfort.
- nausea and vomiting
- Abdominal pain
- muscle or joint pain
- Fast breathing
- fast heart rate
Some people who have malaria experience cycles of malaria “attacks.” An attack usually begins with chills and chills, followed by a high fever, sweats, and a return to normal temperature. The signs and symptoms of malaria usually begin a few weeks after being bitten by an infected mosquito. However, some types of malaria parasites can remain dormant in your body for up to a year.
When to see a doctor
Talk to your doctor if you experience a fever while living in or after travelling to a high-risk malaria region. If you have severe symptoms, seek emergency medical attention.
Malaria is caused by a unicellular parasite of the genus Plasmodium. The parasite is most commonly transmitted to humans through mosquito bites.
Mosquito transmission cycle
- Uninfected mosquito. A mosquito becomes infected by feeding on a person who has malaria.
- Transmission of the parasite. If this mosquito bites you in the future, it can transmit malaria parasites to you.
- In the liver. Once the parasites enter your body, they travel to your liver, where some types can lie dormant for up to a year.
- In the bloodstream. When the parasites mature, they leave the liver and infect red blood cells. This is when people usually develop malaria symptoms.
- To the next person. If you are bitten by an uninfected mosquito at this point in the cycle, it will become infected with malaria parasites and can pass them on to other people it bites.
Other modes of transmission
Because the parasites that cause malaria affect red blood cells, people can also get malaria from exposure to infected blood, including:
- From mother to unborn child
- Through blood transfusions.
- By sharing needles used to inject drugs
The biggest risk factor for developing malaria is living in or visiting areas where the disease is common. These include the tropical and subtropical regions of:
- Sub-Saharan Africa
- South and Southeast Asia
- pacific islands
- Central America and northern South America
The degree of risk depends on local malaria control, seasonal changes in malaria rates, and the precautions you take to avoid mosquito bites.
Risks of a more serious illness
People at higher risk for serious illness include:
- toddlers and babies
- Older adults
- Travelers from malaria-free areas
- Pregnant women and their unborn children
In many countries with high rates of malaria, the problem is compounded by a lack of access to preventive measures, medical care and information.
Immunity may decrease
Residents of a region with malaria may be exposed enough to the disease to acquire partial immunity, which can lessen the severity of malaria symptoms. However, this partial immunity can disappear if you move to a place where you are no longer frequently exposed to the parasite.
Malaria can be fatal, particularly when caused by Plasmodium species common in Africa. The World Health Organization estimates that around 94% of all malaria deaths occur in Africa, most commonly in children under 5 years of age. Malaria deaths are usually related to one or more serious complications, including:
- Cerebral malaria. If parasite-filled blood cells block small blood vessels in the brain (cerebral malaria), brain swelling or brain damage can occur. Cerebral malaria can cause seizures and coma.
- Respiratory problems. Fluid built up in the lungs (pulmonary oedema) can make it hard to breathe.
- Organ failure. Malaria can damage the kidneys or liver or cause the spleen to rupture. Any of these conditions can be life-threatening.
- Anaemia. Malaria can cause you do not to have enough red blood cells to adequately supply your body’s tissues with oxygen (anaemia).
- Low blood sugar. Severe forms of malaria can cause low blood sugar (hypoglycemia), as can quinine, a common medicine used to combat malaria. Very low blood sugar can cause coma or death.
Malaria may reappear
Some varieties of the malaria parasite, which usually cause milder forms of the disease, can persist for years and cause relapses.
If you live in or travel to an area where malaria is common, take steps to avoid mosquito bites. Mosquitoes are most active between dusk and dawn. To protect yourself from mosquito bites, you should:
- Cover your skin. Wear pants and long-sleeved shirts. Put on your shirt and tuck your pant legs into your socks.
- Apply insect repellent to the skin. Use an insect repellent registered with the Environmental Protection Agency on any exposed skin. These include repellents that contain DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), para-menthane-3,8-diol (PMD), or 2-undecanoate. Do not use a spray directly on your face. Do not use products with OLE or PMD in children under 3 years of age.
- Apply repellent to clothing. Sprays containing permethrin are safe to apply to clothing.
- Sleep under a net. Bed nets, particularly those treated with insecticides such as permethrin, help prevent mosquito bites while you sleep.
If you’re travelling to a place where malaria is common, talk to your doctor a few months beforehand about whether you should take medication before, during, and after your trip to help protect you from malaria parasites. In general, the medicines taken to prevent malaria are the same ones used to treat the disease. The medicine you take depends on where and how long you travel and on your own health.
The World Health Organization has recommended a malaria vaccine for use in children living in countries with a high number of malaria cases. Researchers continue to develop and study malaria vaccines to prevent infection.