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P. falciparum microgametocyte. 
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Malaria is a disease caused by parasites called Plasmodium which infect blood cells.  Humans get infected through the bite of an infected Anopheles mosquito.  Malaria generally occurs in tropical and subtropical areas, where altitude is below 1,500 m, as this is where the parasite can multiply in the mosquito vector.  Cases in the United States are usually in travelers and immigrants returning from countries where malaria transmission occurs, mainly from sub-Saharan Africa and South Asia.  The four main Plasmodium species affecting humans are P. falciparum, P. vivax, P. ovale, and P. malariae. 



Symptoms of uncomplicated malaria are non-specific and may include fever, chills, headache, muscle and joint pain, weakness, vomiting and diarrhea.  Health care professionals should consider malaria in any patient presenting with a febrile illness and a history of travel to an area where malaria occurs naturally.  P. falciparium infections are the most likely to progress to the severe, potentially fatal forms with central nervous system involvement, kidney failure, severe anemia, or respiratory distress.

Malaria is reportable in Orange County within one (1) working day of identification.  To report a case, health care providers/facilities should call OCHCA Epidemiology at 714-834-8180 or fax records to 714-560-4050.  Two to nine cases of malaria were reported each year in Orange County between 2013 and 2017. 

Healthcare Professionals

For more information, see the Centers for Disease Control (CDC) website

Last reviewed January 23, 2019