Malaria Transmission in the United States
Outbreaks of locally transmitted cases of malaria in the United States have been small and relatively isolated, but the potential risk for the disease to re-emerge is present due to the abundance of competent vectors, especially in the southern states. At the request of the states, CDC assists in these investigations of locally transmitted mosquito-borne malaria.
“Airport” malaria refers to malaria caused by infected mosquitoes that are transported rapidly by aircraft from a malaria-endemic country to a non-endemic country. If the local conditions allow their survival, they can bite local residents who can thus acquire malaria without having traveled abroad.
In congenital malaria, infected mothers transmit parasites to their child during pregnancy before or during delivery. Therefore, though congenital transmission is rare, health-care providers should be alert to the diagnosis of malaria in ill neonates and young infants, particularly those with fever.
During evaluation, health-care providers should obtain a complete and accurate travel and residency history on the patient and close relatives. Patients should be asked about transfusion of blood products.
The absence of recent foreign travel or a long interval between immigration of the mother and the birth of the infant being examined should not discourage clinicians from obtaining blood films on the patient to rule out a potentially life-threatening but treatable infection.
Transfusion-transmitted malaria is rare in the United States, but it is a potential severe complication in blood recipients. On average, only one case of transfusion-transmitted malaria occurs in the United States every 2 years.
Because no approved tests are available in the United States to screen donated blood for malaria, prevention of transfusion-transmitted malaria requires careful questioning of prospective donors.
More on: Blood Banks
Summary of guidelines of the Food and Drug Administration and American Association of Blood Banks for deferral of blood donors at increased risk for malaria
Defer blood donation for 1 year
- Travelers who are residents of nonmalarious areas who have been in a malarious area may be accepted as donors 1 year after their return to the nonmalarious area (irrespective of the use of chemoprophylaxis) if they have been free of malaria symptoms.
Defer blood donation for 3 years
- Immigrants or visitors from malarious areas may be accepted 3 years after departure from the area if they have been asymptomatic. Former residents of malarious areas who now live in the United States but who return to visit a malarious area may be accepted as donoros 3 years after their most recent visit.
- Persons who have had a diagnosis of malaria should be deferred for 3 years after becoming asymptomatic.
- Mungai M, Tegtmeier G, Chamberland M, Parise M. Transfusion-transmitted malaria in the United States from 1963 through 1999. N Engl J Med 2001:344:1973-8.
- Zoon K. Recommendations for deferral of donors for malaria risk: letter to all registered blood establishments. Washington, DC: Food and Drug Administration, 1994.
- American Association of Blood Banks. Standards for blood banks and transfusions services, 21st ed. Bethesda, Maryland: American Association of Blood Banks, 2002.