Malaria (patient information)
Malaria On the Web
Malaria is a disease caused by a parasite and transmitted by the anopheles mosquito. Initial symptoms of the disease commonly include: malaise, fever, chills, sweating, headache, nausea, and vomiting. More severe stages of the disease are potentially life-threatening and may manifest with symptoms such as, respiratory difficulties, confusion, and coma. There are five types of parasites that may cause malaria, Plasmodium falciparum, P. vivax, P. oval, P. malaria, and more recently P. knowlesi. Anyone can contract malaria, however, certain individuals are at a higher risk, including those who live in countries where malaria is endemic. The disease may be diagnosed based upon the manifestation of symptoms and by laboratory tests, such as microscopic diagnosis and antigen detection. Malaria may be treated with a combination of several drugs, dependent on the region where the person was infected with the disease. People traveling to regions where malaria is endemic should take preventive medications and follow precautionary measures, such as the use of mosquito repellents and protective clothing over the arms and legs. Most forms of malaria have a good prognosis when adequately treated.
What are the symptoms of Malaria?
Common symptoms of malaria include:
The classically described progression of the disease, is as follows:
- Cold stage - where the patient experiences a sensation of chills and shivering
- Hot stage - characterized by fever, headaches, and seizures, frequently experienced by children
- Sweating stage - characterized by sweating and exhaustion upon the return to normal temperature
Following an infective bite by the Anopheles mosquito, a period of time (the "incubation period") passes before the first symptoms manifest. The incubation period in most cases varies from 7 to 30 days.
What causes Malaria?
Malaria is caused by a parasite that commonly infects a certain type of mosquito which feeds on humans. The disease may be transmitted from one human to another by the bite of infected Anopheles mosquitoes.
Four kinds of malaria parasites have long been known to infect humans:
- Plasmodium falciparum
- P. vivax
- P. ovale
- P. malariae
- P. knowlesi - a recently recognized type of malaria parasite, naturally infecting macaques in Southeast Asia as well as humans, which results in malaria transmission from animal to human ("zoonotic" malaria).
Falciparum malaria, one of the five different types of malaria, affects a greater proportion of the red blood cells than the other types, making it significantly more serious. It can be fatal within a few hours of the manifestation of the primary symptoms.
Malaria can also be transmitted from a mother to her unborn baby (congenitally) and by blood transfusions.
Malaria can be carried by mosquitoes in temperate climates, but the parasite is inactive over the winter.
In certain areas of the world, mosquitoes that carry malaria have developed resistance to insecticides and some antibiotics. This has led to difficulty in controlling both the rate of infection and subsequent spread of the disease.
Who is at highest risk?
- Anyone is at risk to contract malaria.
- Most cases occur in people who live in countries where malaria is endemic.
- People who live in countries where malaria is not endemic, may also get the disease when they travel to such countries, or through blood transfusions.
- Malaria may also be transmitted from an infected mother to her infant before or during delivery.
Who is at Highest Risk of Dying from Malaria?
- People who are heavily exposed to the bites of mosquitoes infected with P. falciparum (causes severe and life-threatening malaria) are at the highest risk of dying from malaria.
- People who live in African countries south of the Sahara desert, where P. falciparum is common
- People who have little or no immunity to malaria, such as young children, pregnant women, and travelers coming from areas without endemic malaria
- Individuals in poverty who live in rural areas and lack access to health care
When to seek urgent medical care?
Urgent medical care should be sought when:
- Symptoms of malaria manifest while traveling to a country where malaria is endemic
- Travelers who become ill with a fever or flu-like illness, either while traveling in a malaria-risk area, or following their return home (for up to 1 year). For this reason, is essential that individuals report travel history to their health-care provider.
Health-care providers should always obtain a travel history from febrile patients. The manifestation of fever in individual who recently traveled to a malaria-endemic area should be immediately evaluated using the appropriate diagnostic tests for malaria.
Clinical diagnosis is based on the patient's symptoms and physical findings upon examination. The initial symptoms of malaria often are not specific and are characteristic of other diseases (such as the "flu" and common viral infections). Likewise, the physical findings are frequently not specific.
In severe malaria clinical findings are more striking, increasing the index of suspicion for malaria. These may include:
Clinical findings should be confirmed with a laboratory test for malaria. these diagnostic tests may include:
In addition to ordering the malaria specific diagnostic tests described above, the health-care provider should conduct an initial workup and request:
- Complete blood count
- Routine chemistry panel
In the event that the person does test positive for malaria, additional tests will be useful in determining whether the patient has uncomplicated or severe manifestations of the infection. Specifically, these tests can detect:
Malaria can be a severe, potentially fatal disease (especially when caused by Plasmodium falciparum) and treatment should be initiated as rapidly as possible.
Treatment of malaria is dependent on numerous factors including:
- Disease severity
- Species of malaria parasite causing the infection
- Part of the world in which the infection was acquired
These latter two characteristics help determine the probability that the organism is resistant to certain antimalarial drugs. Patients who have severe P. falciparum malaria, or who cannot take oral medications, should be given treatment by continuous intravenous infusion.
Most drugs used in treatment are active against the parasite forms in the blood (the form that causes disease) and include:
- Doxycycline (used in combination with quinine)
- Clindamycin (used in combination with quinine)
The choice of medication is dependent upon the location of the patient when he/she was infected. Aggressive supportive medical care, including intravenous (IV) fluids, other medications, and breathing (respiratory) support may be needed.
Where to find medical care for Malaria?
- Most people living in areas where malaria is common acquire some immunity to the disease.
- Visitors, who do not possess any immunity, should take preventive medications. It is important to see a health care provider well before a trip, because treatment may begin as long as 2 weeks prior to travel, and continue for a month after you leave the area.
- The types of anti-malarial medications prescribed will depend on the area an individual visits. According to the CDC, travelers to South America, Africa, the Indian subcontinent, Asia, and the South Pacific should take one of the following drugs:
- Pregnant women should take preventive medications, because the likelihood of the fetus having side-effects from the medications is less than the risk of acquiring a congenital infection.
- People on anti-malarial medications can still be infected. Mosquito bites can be avoided by wearing protective clothing over the arms and legs, using screens on windows, and using insect repellent.
- Chloroquine has been the drug of choice for prevention of malaria. But because of resistance, it is now only suggested for use in areas where Plasmodium vivax, P. oval, and P. malariae are present. Falciparum malaria is becoming increasingly resistant to anti-malarial medications.
- For travelers going to areas where Falciparum malaria is known to manifest, there are several options for malaria prevention, including:
What to expect (Outlook/Prognosis)?
In most cases, the prognosis of malaria is positive with prompt and proper treatment.
The prognosis of Falciparum malaria is poor due to the severity of the disease.
Complications of malaria occur mainly in the more severe forms of the disease. Severe malaria occurs when infections are complicated by serious organ failures or abnormalities in the patient's blood or metabolism. Manifestations of severe malaria include:
- Cerebral malaria
- Severe anemia
- Respiratory failure from fluid in the lungs (pulmonary edema)
- Acute respiratory distress syndrome (ARDS)
- Abnormalities in blood coagulation
- Cardiovascular collapse
- Acute kidney failure
- Liver failure
- Rupture of the spleen leading to massive internal bleeding (hemorrhage)
Quartan malaria; Falciparum malaria; Biduoterian fever; Blackwater fever; Tertian malaria; Plasmodium