MALARIA IS CAUSED by a parasite spread by the bite of infected female Anopheles mosquitos found in tropical and subtropical regions of the world. In 2015, an estimated 214 million malaria cases and 438,000 deaths were reported worldwide.1,2 Although the United States was declared malaria-free in the 1950s, 1,500 cases are still reported each year, nearly all associated with recent travel or immigration from an endemic region.1,3,4 However, the three Anopheles species responsible for malaria transmission before the 1950s are still found in the United States, so a threat of transmission within the continental United States still exists. Although experimental vaccine trials are underway at the National Institutes of Health, no effective vaccine is currently available.5
Four kinds of the Plasmodium parasite cause most malaria in humans: P. falciparum, P. vivax, P. ovale, and P. malariae.4 P. falciparum is the type of malaria most likely to cause severe illness and death. The CDC estimates that 90% of deaths due to malaria occur in sub-Saharan Africa, and most fatalities occur in children age 5 or younger.4
The malaria parasite is transmitted when an Anopheles mosquito becomes infected by biting a human previously infected with the parasite. The incubation time within the mosquito is 10 to 18 days, during which the sporozoites populate the insect's salivary glands and can be injected when it bites a second person. The microscopic parasites are then released into that person's bloodstream.6 Now infected, this person may also pass on the disease via another mosquito, completing the cycle of infection.4
Malaria isn't transmitted directly from person to person via casual contact. However, although rare, bloodborne transmission is possible because the parasite is carried in the infected person's red blood cells. Consequently, transmission can occur during blood transfusion, organ donation, and sharing of contaminated needles.4 It can also pass from mother to baby during birth (congenital malaria).4
From 1963 to 2015, 97 cases of transfusion-transmitted malaria were reported in the United States. An estimated two-thirds of these cases might have been prevented if the donors had been deferred per established blood donation guidelines that reject potential donors who've recently traveled to endemic areas.4
Those at highest risk of malaria-related illness and death are people with reduced immunity, such as young children, the immunosuppressed, older adults, and pregnant women. Malaria during pregnancy can infect the placenta and cause maternal anemia, miscarriage, premature delivery, low birth weight, and congenital malaria.7
The incubation period for malaria varies by strain: approximately 9 to 14 days for P. falciparum, 12 to 18 days for P. vivax and P. ovale, and 18 to 40 days for P. malariae. There are exceptions, particularly with P. vivax, which can show a late onset up to 12 months after infection. In some people, dormant parasites may become reactivated years after the primary infection.7 For these reasons, a good patient history should include specific questions about travel within the past year as well as history of past infection.
Signs and symptoms
Healthcare providers should consider malaria as a possible diagnosis in febrile patients who've traveled to or lived in malaria-endemic areas during the preceding 12 months, and in those who may have received blood products, tissue, or organs from someone who's been to such areas. Early clinical signs and symptoms of P. falciparum malaria, the most dangerous type of human malaria, can resemble those of other febrile illnesses and include fever, diaphoresis, chills, headache, myalgia, arthralgia, muscle weakness, vomiting, cough, diarrhea, and abdominal pain.8 Children may be irritable, refuse to eat, and vomit. Manifestations of congenital malaria resemble those of neonatal sepsis, with fever and such nonspecific signs and symptoms as poor appetite, irritability, and lethargy.9
If treatment is delayed, the disease progresses to a more severe illness and possible death. Clinical features of severe malaria may include the above plus decreased level of consciousness including coma, seizures, acute respiratory distress syndrome, kidney failure, shock, hepatic failure, jaundice, severe anemia, and coagulopathy.7,8 Mortality with early treatment is 0.3% in uncomplicated malaria, but it increases to 15% to 20% after complications occur. Untreated P. falciparum malaria is almost always fatal.7
The other human malarias (P. vivax, P. ovale, and P. malariae) aren't usually life-threatening. Signs and symptoms generally start with malaise and fever for several days, followed by chills, increasing fever, headache and nausea, and profuse diaphoresis. Signs and symptoms may be cyclic, with fever and fever-free intervals occurring daily, every other day, or every third day. An untreated primary infection can last a month or more and may be accompanied by prostration, anemia, and splenomegaly with possible splenic rupture.7 Relapses can occur for several years after the primary infection, particularly with P. vivax and P. ovale.9
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Consultations with the CDC are available by phone. Providers needing assistance with diagnosis or management of suspected malaria cases should call the CDC Malaria Hotline: 770–488–7788 or 855–856–4713 toll-free (Monday through Friday, 9 a.m. to 5 p.m., ET). After-hours emergency consultation can be made by calling 770–488–7100 and requesting to speak with a CDC Malaria Branch clinician.11
For information when counseling international travelers before a trip, providers should always check the CDC webpage http://wwwnc.cdc.gov/travel/destinations/list for current information on vaccine recommendations, malaria prophylaxis, and any possible outbreaks.12
Lab tests include a complete blood cell count and chemistry panel, to help determine disease severity. Microscopic examination of thin and thick blood smears after staining should show the parasites and the level of invasion; these tests should be done as soon as possible. A Rapid Diagnostic Test (RDT) for malaria antigen is available for some hospitals and diagnostic labs. It's recommended to be used in conjunction with microscopy but it may not be available to use in a timely manner in many community hospitals.7,10,11
After malarial parasites have been identified by smear and/or RDT, a polymerase chain reaction test may be performed to confirm the species of parasite. Blood may be obtained for serology (immunofluorescence or enzyme-linked immunosorbent assay), although this is useful only in determining past exposure, not current infection. Testing for drug resistance can be done, but only in specialized labs. Advice for testing can be obtained via the CDC hotline (see Malaria resources).7,10,11
Drugs used to treat malaria include chloroquine, atovaquone-proguanil, artemether/lumefantrine, mefloquine, quinine, quinidine, doxycycline or clindamycin (both are used in combination with quinine), and possibly artesunate, which isn't licensed for use in the United States but may be made available through the CDC. The choice of drug therapy is based on the infecting species and possible drug resistance based on the area where exposure occurred (if known), history of prior infection with treatment as a clue to possible resistance, severity of signs and symptoms, the patient's age, and pregnancy status.13 Familiarity with the drug therapy is imperative as adverse drug reactions are common and several drugs are contraindicated in pregnancy.13,14
Aggressive treatment of patients with severe malaria may include use of I.V. quinidine, which should be initiated as soon as possible after the diagnosis. Consultation with a cardiologist and a physician with experience treating malaria is advised when treating patients with quinidine. During administration, continuous BP monitoring for hypotension and cardiac monitoring for widening of the QRS complex and/or lengthening of the QTc interval is indicated, and blood glucose levels should be monitored periodically to prevent hypoglycemia. Cardiac complications may require rate adjustment or discontinuation of the infusion.13
Patients who have severe P. falciparum malaria or who can't take oral medications should be treated by continuous I.V. infusion.10 A treatment chart and decision tree algorithm are available on the CDC Quick Link at www.cdc.gov/malaria/diagnosis_treatment/index.html.13
Nursing care of a patient with malaria includes administering antibiotics, I.V. fluids, and pain medication as prescribed. Depending on acuity, the patient may be admitted to the ICU for continuous cardiac and BP monitoring and treatment with antiseizure medications and possibly blood transfusions. Initiate seizure precautions as appropriate.
The nurse should carefully document trends in fever. Isolation precautions aren't necessary, but because bloodborne transmission can occur, standard precautions and hand hygiene protocols must be strictly enforced. Patient and family teaching must be included and documented as well.
Prevention of infection is key to control when living or traveling in a malaria-endemic region. The Anopheles mosquitos are most active between dusk and dawn, so being outside at night or sleeping in unscreened rooms increases risk. Advise patients traveling to endemic regions to wear long-sleeved shirts, long pants, and hats when outdoors, and to apply insect repellant to exposed skin.15 The use of an insecticide-treated bed net at night helps prevent night-flying mosquitos from feeding. Anopheles mosquitos lay their eggs on water surface and their larvae and pupa live in the water, so eliminating standing pools of water wherever possible reduces breeding grounds.4,16
Antimalarial chemoprophylaxis is essential for people traveling to malarious areas, and treatment should start before travel in order to ensure adequate serum drug levels and to monitor for adverse drug reactions (depending on the drug used) before travel, with sufficient time to change the medication regimen if necessary. Advice on which countries are considered at risk and which medication should be taken for that region is available on the CDC's website and through state health departments. Health considerations, age, and pregnancy should be taken into consideration and a prophylactic regimen tailored to the individual.
Teach patients about the seriousness of malaria and the importance of adhering to the prophylactic regimen, which may be prescribed to extend for several weeks beyond return from the endemic area. Women of childbearing potential should be advised to consult with their healthcare provider about delaying pregnancy until a period of time has elapsed after the trip as well as the potential effects of chemoprophylaxis during pregnancy.7
The World Health Organization's December 2015 World Malaria Report showed that eliminating malaria from 35 countries by 2030 and reducing the number of cases by 90% are ambitious but achievable goals.17 Malaria mortality has declined by 60% globally since 2000. Nurses can contribute to improved rates of morbidity and mortality by educating their patients about malaria prevention and self-care.