Malaria

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.

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.
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.

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.

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

COMPLICATIONS
Malaria can be fatal, particularly the variety that's common in tropical parts of Africa. The Centers for Disease Control and Prevention estimate that 90 percent of all malaria deaths occur in Africa — most commonly in children under the age of 5.

In most cases, malaria deaths are related to one or more of these serious complications:

Cerebral malaria. If parasite-filled blood cells block small blood vessels to your brain (cerebral malaria), swelling of your brain or brain damage may occur. Cerebral malaria may cause coma. Breathing problems. Accumulated fluid in your lungs (pulmonary edema) can make it difficult to breathe. Organ failure. Malaria can cause your kidneys or liver to fail, or your spleen to rupture. Any of these conditions can be life-threatening. Severe anemia. Malaria damages red blood cells, which can result in severe anemia. Low blood sugar. Severe forms of malaria itself can cause low blood sugar, as can quinine — one of the most common medications used to combat malaria. Very low blood sugar can result in coma or death.

Malaria may recur

Some varieties of the malaria parasite, which typically cause milder forms of the disease, can persist for years and cause relapses.

DIAGNOSIS
Blood tests can show the presence of the parasite and help tailor treatment by determining:

Whether you have malaria Which type of malaria parasite is causing your symptoms If your infection is caused by a parasite resistant to certain drugs Whether the disease is affecting any of your vital organs

Some blood tests can take several days to complete, while others can produce results in less than 15 minutes.

TREATMENT
The types of drugs and the length of treatment will vary, depending on:

Which type of malaria parasite you have The severity of your symptoms Your age Whether you're pregnant

Medications

The most common antimalarial drugs include:

Chloroquine (Aralen) Quinine sulfate (Qualaquin) Hydroxychloroquine (Plaquenil) Mefloquine Combination of atovaquone and proguanil (Malarone)

The history of antimalarial medicine has been marked by a constant struggle between evolving drug-resistant parasites and the search for new drug formulations. In many parts of the world, for instance, resistance to chloroquine has rendered the drug ineffective.