Malaria

DEFINITION

Malaria is a disease caused by a parasite, transmitted by the bite of infected mosquitoes. Malaria produces recurrent attacks of chills and fever. Malaria kills an estimated 1 million people each year worldwide. 

While the disease is uncommon in temperate climates, malaria is still prevalent in tropical and subtropical countries. World health officials are trying to reduce the incidence of malaria by distributing bed nets to help protect people from mosquito bites as they sleep. Scientists around the world are working to develop a vaccine to prevent malaria. 

If you’re traveling to locations where malaria is common, take preventive medicine before, during and after your trip. Many malaria parasites are now immune to the most common drugs used to treat the disease.

CAUSES

Malaria is caused by a type of microscopic parasite that’s transmitted most commonly by mosquito bites. 

Mosquito transmission cycle 

Uninfected mosquito. A mosquito becomes infected by feeding on a person who has malaria. 

Transmission of parasite. If you’re the next person this mosquito bites, it can transmit malaria parasites to you. 

In the liver. The parasites then travel to your liver — where they can lie dormant for as long as a year. 

Into the bloodstream. When the parasites mature, they leave the liver and infect your red blood cells. This is when people typically develop malaria symptoms. 

On to the next person. If an uninfected mosquito bites you at this point in the cycle, it will become infected with your malaria parasites and can spread them to the next person it bites. 

Other modes of transmission 

Because the parasites that cause malaria affect red blood cells, people can also catch malaria from exposures to infected blood, including: 

• From mother to unborn child
• Through blood transfusions
• By sharing needles used to inject drugs

SYMPTOMS

A malaria infection is generally characterized by recurrent attacks with the following signs and symptoms:

• Moderate to severe shaking chills
• High fever
• Profuse sweating as body temperature falls
• Other signs and symptoms may include:
• Headache
• Vomiting
• Diarrhea

Malaria signs and symptoms typically begin within a few weeks after being bitten by an infected mosquito. However, some types of malaria parasites can lie dormant in your body for months, or even years.

When to see a doctor 

Talk to your doctor if you experience a high fever while living in or after traveling to a high-risk malaria region. The parasites that cause malaria can lie dormant in your body for months. If you have severe symptoms, seek emergency medical attention.