Malaria is caused by a parasite (Plasmodium) that is transmitted to humans via the bite of an infected female Anopheles mosquito. In humans, the parasites grow and multiply first in the liver and then in the red blood cells. Eventually, the red blood cell is destroyed, releasing daughter parasites which go on to invade other red cells.
Malaria is most often reported in the tropical areas of the world but can still occur in more temperate climates such as in the United States where Anopheles mosquitoes are present. However, nearly all of the 1000 cases reported in the United States annually are acquired abroad.
Malaria is reportable to the Iowa Department of Public Health by Iowa Administrative Code 641 IAC 1 .
Symptoms of malaria can occur between 7 to 40 days after infection. Typical symptoms include the following:
- High fever with chills
Other, less common, symptoms may include:
- Joint aches
- Respiratory distress
- Abdominal pain
- Back pain
Symptoms may vary depending on the species of parasite the individual was infected with. Infection with some species of Plasmodium parasites may result in a potentially fatal, acute illness with the following symptoms:
- Blood clotting defects
- Kidney and liver failure
- Fluid in the lungs or around the brain
Infections may last from a week to a month or longer and relapses are possible. Chronic infections may also occur with or without recurrent episodes of fever and often result in enlargement of the liver and spleen.
People usually become infected with malaria from the bite of an infected mosquito. Only mosquitoes infected with malaria parasites (from a previous blood meal taken from an infected person) can transmit the disease. Rarely, malaria can also be transmitted through blood transfusions, organ transplants, or shared use of contaminated needles and syringes. It may also be transmitted from a mother to her fetus before or during delivery.
People who are living in or travel to tropical areas where malaria is common are at an increased risk of becoming infected.
In tropical areas where malaria is common, people should protect themselves from being bitten by mosquitoes as follows:
- Sleep inside bed nets and treat bed nets with insecticides
- Sleep in houses that are screened or air-conditioned
- Avoid exposure to mosquitoes between dusk and dawn
- If outdoors, apply insect repellants containing DEET to exposed skin
- Wear long-sleeved clothing or clothing treated with permethrin
The use of anti-malarial drugs, which can be obtained from your health care provider if you are traveling to a malaria-infected region, is also recommended.
Treatment varies widely and is dependent on the severity of the disease, the species of parasite infecting the individual and much more. There are several different kinds of anti-malarial drugs available but some species of Plasmodium parasites have become resistant to many of these drugs. Severe infections may result in hospitalization and require IV drug treatments. If you suspect you may have been infected, seek care from your health care provider immediately.
In 2021, 17 cases of malaria were identified in Iowa. All infections were acquired outside of the United States.
For more detailed information and statistics on all notifiable diseases, please see our current annual report located in the reports section of the CADE homepage.