Malaria Acquired in Haiti --- 2010

On January 12, 2010, a 7.0 magnitude earthquake struck Haiti, which borders the Dominican Republic on the island of Hispaniola. The earthquake's epicenter was 10 miles west of the Haiti capital city of Port-au-Prince (estimated population: 2 million). According to the Haitian government, approximately 200,000 persons were killed, and 500,000 were left homeless (1). Malaria caused by Plasmodium falciparum infection is endemic in Haiti, and the principal mosquito vector is Anopheles albimanus, which frequently bites outdoors. Thus, displaced persons living outdoors or in temporary shelters and thousands of emergency responders in Haiti are at substantial risk for malaria. During January 12 --February 25, CDC received reports of 11 laboratory-confirmed cases of P. falciparum malaria acquired in Haiti. Patients included seven U.S. residents who were emergency responders, three Haitian residents, and one U.S. traveler. This report summarizes the 11 cases and provides chemoprophylactic and additional preventive recommendations to minimize the risk for acquiring malaria for persons traveling to Haiti.

Of the seven emergency responders, six were U.S. military personnel. Among the six, four cases were uncomplicated and treated locally in Haiti. Two other patients were moderately to seriously ill and transferred to the United States for intensive care; one required intubation and mechanical ventilation for acute respiratory distress syndrome. All are expected to make a full recovery.

All six military personnel had been provided oral chemoprophylaxis with doxycycline before departure from the United States and personal protective equipment (e.g., insect repellent and insecticide-treated netting and uniforms) after arrival in Haiti. Of the 11 total patients, chemoprophylaxis was indicated for the seven emergency responders and the lone U.S. traveler. Six of these eight patients (including the two hospitalized military personnel) reported nonadherence to the recommended malaria medication regimen. Adherence status was unknown for the remaining two patients.

Three cases occurred in Haitian residents who traveled to the United States, including one Haitian adoptee. The number of U.S. malaria cases imported from Haiti likely is underestimated because typically not all cases are reported to CDC.

Reported by

K Mung, MD, B Renamy, MSc, Pan American Health Organization. JF Vely, MD, R Magloire MD, Ministry of Public Health and Population, Haiti. N Wells, MD, US Navy Medical Corps, J Ferguson, DO, US Army Medical Corps. D Townes, MD, M McMorrow, MD, K Tan, MD, B Divine, L Slutsker, MD, Malaria Br, Div of Parasitic Diseases, Center for Global Health, CDC.

Editorial Note

In 2008, a total of 1,298 cases of malaria in the United States were reported provisionally to CDC, and 527 (40.6%) were caused by P. falciparum; all but two of the malaria cases were imported (CDC, unpublished data, 2009). Most imported cases are in travelers returning to the United States from areas in Africa, Asia, and the Americas where malaria transmission is known to occur (2). Of the four Plasmodium species that routinely infect humans (P. falciparum, P. vivax, P. malariae, and P. ovale), P. falciparum causes the most severe disease and highest mortality and is the predominant species in Haiti (3,4). Information regarding the incidence of malaria in Haiti is limited. Historically, malaria transmission peaks in Haiti after the two rainy seasons, with a primary peak during November--January and a secondary peak during May--June. Although each year Haiti reports approximately 30,000 confirmed cases of malaria to the Pan American Health Organization, as many as 200,000 cases might occur annually. One population-based survey in 2006 in the Artibonite Valley, located 75 miles north of Port-au-Prince, found an overall prevalence of P. falciparum infection of 3.1% (14.2% in febrile and 2.1% in nonfebrile persons) (4).

Prompt diagnosis and treatment of malaria as well as chemoprophylaxis when appropriate are critical. Recommendations for antimalarials for treatment and prevention are based on information on parasite drug susceptibility for a specific geographic setting. In Haiti, the first-line treatment for malaria is chloroquine. No evidence exists of clinical failure of chloroquine treatment in persons with P. falciparum infection acquired in Hispaniola, nor has chloroquine prophylaxis failure been documented in travelers. However, one published study found five of 79 (6.3%) P. falciparum isolates collected in the Artibonite Valley in Haiti in 2006 and 2007 carried a mutation associated with parasite resistance to chloroquine (5). Although the findings do not serve as a basis for prophylaxis and treatment policy change, they do point out the need for heightened awareness of potential failure of chloroquine treatment or prophylaxis in persons in Haiti or returning from Haiti.

Persons traveling to Haiti should receive chemoprophylaxis with one of the following medications: atovaquone-proguanil, chloroquine, doxycycline, or mefloquine (6). If preventive medications are started <1 week before departure, or while already in Haiti, either atovaquone-proguanil or doxycycline are recommended. Use of weekly chloroquine requires receiving the initial dose 1 week before departure, and use of weekly mefloquine requires receiving the initial dose 2 weeks before departure. Mosquito avoidance measures should be taken, such as using mosquito repellent, wearing protective clothing, and sleeping under an insecticide-treated mosquito net. Chemoprophylaxis, although highly effective in preventing malaria, is not 100% effective. Therefore, if fever develops in persons taking chloroquine or other antimalarials for chemoprophylaxis, they still should be evaluated for malaria infection with a diagnostic test.

CDC currently recommends microscopic examination of blood smears for malaria diagnosis. Three negative malaria smears spaced 12--24 hours apart are needed to rule out malaria. However, microscopy capacity in Haiti is limited at this time. A diagnostic option frequently used in emergency settings in areas with high prevalence of malaria is a rapid diagnostic test based on antigen detection. However, if laboratory diagnosis of malaria is not possible, presumptive treatment based on clinical suspicion of malaria (e.g., unexplained fever) should be given. Rapid diagnostic tests for malaria can remain positive up to 3 weeks after treatment and should not be used to assess treatment failure in a patient with malaria.

Persons with laboratory-confirmed P. falciparum malaria acquired in Haiti and treated in the United States and emergency responders treated in the field should receive treatment according to CDC guidelines (7). Uncomplicated malaria can be treated with one of the following regimens: chloroquine, artemether-lumefantrine, atovaquone-proguanil, or the combination of quinine and doxycycline, tetracycline, or clindamycin. In patients with confirmed malaria who report adherence to chemoprophylaxis in Haiti, a change to a different drug than that taken for chemoprophylaxis is recommended for treatment. Clinicians should consider switching patients with uncomplicated, laboratory-confirmed malaria from chloroquine treatment to other recommended drugs after any indication of poor response to chloroquine such as increasing parasite density 24 hours after starting treatment, persistent parasitemia 48 hours after starting treatment, or clinical deterioration. Severe malaria requires treatment with intravenous quinidine and one of the following: doxycycline, tetracycline, or clindamycin. Intravenous artesunate also is available from CDC for use in the United States as part of an investigational drug protocol. If treating severe malaria in a responder in the field, treatment should be initiated with available medications and consideration given to immediate medical evacuation.

In Haiti, residents with malaria should be treated in accordance with that country's national treatment guidelines. First-line treatment for uncomplicated malaria in Haiti is chloroquine. First-line treatment for severe malaria in Haiti is intravenous or intramuscular quinine.

CDC continues to monitor the malaria situation in Haiti, including any reports of possible chloroquine prophylaxis or treatment failures in those returning from Haiti. Medical providers should contact the CDC Malaria Branch clinician on call (770-488-7100) for clinical consultations and to discuss cases of apparent chloroquine treatment or prophylaxis failures and testing of parasites at CDC for resistance markers. Additional information on malaria is available at http://www.cdc.gov/malaria.

References

1. Information Center of the Haitian Government [French]. February 23, 2010. Available at http://www.haitiseisme2010.gouv.ht. Accessed March 2, 2010.
2. CDC. Malaria surveillance United States, 2007. MMWR 2009;58(No. SS-2).
3. Pan American Health Organization. Roll back malaria in Meso America: report on the meeting held in the Dominican Republic with the participation of the Central American countries, Mexico, Haiti, and the Dominican Republic. San Pedro de Macoris; November 20--24, 2000. Available at http://www.paho.org/common/display.asp?lang=e&recid=4921. Accessed March 2, 2010.
4. Eisele TP, Keating J, Bennett A, et al. Prevalence of Plasmodium falciparum infection in rainy season, Artibonite Valley, Haiti, 2006. Emerg Infect Dis 2007;13:1494--6.
5. Londono BL, Eisele TP, Keating J, et al. Chloroquine-resistant haplotype Plasmodium falciparum parasites, Haiti. Emerg Infect Dis 2009;15:735--40.
6. CDC. Health information for travelers to Haiti. Atlanta, GA: US Department of Health and Human Services, CDC; 2010. Available at http://wwwnc.cdc.gov/travel/destinations/haiti.aspx. Accessed March 2, 2010.
7. CDC. Malaria treatment (United States). Atlanta, GA: US Department of Health and Human Services, CDC. Available at http://www.cdc.gov/malaria/diagnosis_treatment/treatment.html. Accessed March 2, 2010.

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