Malaria

FAQs for Health Care Providers

Malaria Risk, Diagnosis, and Treatment in Afghan Evacuees

Have there been confirmed cases in the Afghan evacuees? Yes

There have been confirmed cases of non-falciparum (P. vivax) in Afghan evacuees.

Epidemiology

There is a high malaria burden in Afghanistan and it occurs throughout the country in areas below 2500 meters. It is seasonal, with the peak season being April-December, when the Afghan evacuation occurred. More than 80% of malaria cases are reported from six provinces (Nangahar, Laghman, Kunar, Nuristan, Khost and Paktika). Species are primarily P. vivax (~95%) and P. falciparum (~5%).

When should I consider malaria?

Clinical Presentation

Fever and a flu-like syndrome is the most common presentation. Individuals with fever, especially when no alternative diagnosis is confirmed, should have a thorough evaluation for malaria. Fever is frequently accompanied by shaking chills, headache and muscle aches. Nausea, vomiting and diarrhea also may occur and are more common in children. Physical examination may be unremarkable but fever, tachycardia, pallor, jaundice and splenomegaly may be observed. Severe malaria (complicated malaria) may present with mental alternation/confusion/coma, seizures, and signs of other end-organ damage like kidney failure. Although P. falciparum is more likely to cause severe disease, P. vivax is also known to cause severe disease and death.

Is malaria contagious? No

Are there special infectious disease precautions for someone with malaria? No

How do I diagnose malaria?

Diagnosis can be difficult, especially in austere settings. The most available tests are malaria blood films (thick and thin smears) and rapid diagnostic testing (RDT). When available in an acute setting, both blood smears and RDT should be performed at the initial encounter (RDT will provide immediate results, blood smear may be more sensitive and is more specific and provides information to inform proper treatment such as the level of parasite density). Polymerase chain reaction testing (PCR), when available, can augment diagnosis.

It must be noted that the only brand of malaria RDT available in the U.S. has lower sensitivity for P. vivax. A negative RDT does not rule out malaria. When there is a high pre-test probability in a patient (a fever with flu-like symptoms without an alternative diagnosis in an Afghan evacuee), a minimum of up to 3 thick and thin blood smear examinations must be performed (12-24 hours apart) before ruling out the diagnosis.

See this CDC flowchart for the standard-of-care approach to diagnosis in the U.S.

What is the treatment for malaria?

Treatment for malaria can be complex and if the clinician is not experienced, consultation with an expert should be sought (see references).

Treatment is based on severity and malaria species.

Any severely ill patient needs immediate treatment. The most common presenting signs and symptoms of severe malaria include CNS findings (abnormal behavior, impaired consciousness, seizures or coma) and cardiovascular or respiratory compromise. Worrisome laboratory findings indicting severe disease include severe anemia (Hb<7), metabolic acidosis, hypoglycemia and very high parasite density on thin blood smear (≥5% of RBC’s infected). Please see table for severe malaria criterion. Any of these findings constitute a medical emergency and hospitalization and intravenous (IV) artesunate are indicated (regardless of species). Acquiring artesunate can take time, so expert consultation early in management is essential. CDC should be consulted for any patient where there is concern for severe malaria (CDC Malaria Hotline M-F 9a-5p EST 770-488-7788 or afterhours 770-488-7100).

Treatment of an individual without signs or symptoms should be approached cautiously as patients can decompensate quickly, especially those with falciparum malaria. Under current circumstances all treatment of malaria in Afghan evacuees should be monitored so patients are not lost to follow-up.

Uncomplicated falciparum malaria and P. vivax both should be treated using a blood-stage treatment. Under the current circumstances, the preferred drugs for blood-stage treatment of both species are atovaquone/proguanil (Malarone™) or artemether/lumefantrine (Coartem™). Other alternatives exist and can be considered in specific circumstances, expert consultation is recommended when considering alternatives.

P. vivax, also known as “relapsing malaria” may have a dormant liver phase (hypnozoite) that will not be eliminated with a blood-stage treatment. Treating the hypnozoite is known as “radical cure”. There are only two drugs available to treat the hypnozoite in the U.S., primaquine and tafenoquine*. Due to the risk of acute hemolytic anemia, these drugs are contraindicated, or need special dosing, in people with G-6-PD deficiency. The prevalence of G-6-PD in Afghanistan varies by population, generally ranging from ~1.5%-5%. It is more common in males with some groups of Afghan males reaching ~10%. It is predominantly “Mediterranean type” which is more associated with hemolytic anemia. All individuals with P. vivax must be tested for G-6-PD prior to radical cure. Radical cure is not urgent and under the current circumstances can be delayed if stable medical care is not available.

It should also be noted that P. vivax, due to the hypnozoite, may cause illness months (and even years) after arrival in the U.S., long after malaria will be considered in a differential diagnosis.

*The use of tafenoquine is not recommended in the current situation because of the need to coadminister it with a specific antimalarial.”

Resources and References

• Centers for Disease Control and Prevention: Malaria.

• Centers for Disease Control and Prevention: Malaria diagnosis and treatment.

• UpToDate: Malaria.