Malaria is a disease caused by parasites of the genus Plasmodium that is transmitted through the bite of an infected female Anopheles mosquito. There are 4 different types of Plasmodium species that cause disease in humans - P. falciparum, P. vivax, P. ovale, and P. malariae. Although Malaria has been eliminated in the Unites States since the early 1950s, cases are still reported in immigrants or travelers returning from malaria-endemic areas.
The two species of Anopheles that were responsible for Plasmodium transmission prior to elimination are still widely present throughout the United States which implies a potential risk for reintroduction of this disease. Because the parasite can be found within red blood cells, the disease may be transmitted through blood transfusion, organ transplant surgery, shared usage of needles or from mother to infant before or during birth.

Signs & Symptoms

Symptoms of malaria include fever and flu-like illness that may present with chills, headaches, muscle aches, and tiredness. Other symptoms of malarial infection include nausea, vomiting, and diarrhea. Jaundice may develop in some cases and if not treated properly, P. falciparum infection may lead to mental confusion, seizures, coma, kidney failure, or death.


Malaria can be suspected based on a patient's travel history, symptoms, and physical findings at examination. For a definitive diagnosis, laboratory tests must demonstrate the malaria parasites or their components. Malaria parasites can be identified by examining a drop of the patient's blood, spread out as a "blood smear," under a microscope. There are also tests available to detect antigens derived from malaria parasites. If you think you may have malaria, please consult with your medical provider for appropriate diagnostic tests and treatment.


Malaria can be a severe, potentially fatal disease and treatment should be initiated as soon as possible. The type of treatment varies depending on the species, the area where the infection was acquired, and the clinical status of the patient. (See CDC's treatment guidelines for further information.)


Proper pre-exposure prophylaxis can reduce or eliminate the possibility of contracting malaria when traveling to endemic areas. Travelers to sub-Saharan Africa have the greatest risk of both getting malaria and dying from their infection. However, all travelers to countries where malaria is present may be at risk for infection. (See CDC's Malaria and Travelers information for further details.)

In Maricopa County

From 2003 and 2009, there were 100 suspect cases of Malaria reported to Maricopa County. Upon investigation, 86 cases were found to be confirmed or probable. All of these cases were acquired while visiting countries outside of the United States.
Malaria Cases Chart
A case is a person identified as meeting the confirmed or probable case definition for the disease. These classifications are for surveillance only and are not used for diagnostic purposes.

Note: These data are based on investigation data maintained by MCDPH and may differ from other case counts presented in other reports by MCDPH and/or ADHS.