Malaria

Description

Malaria in humans is caused by one of four protozoan species of the genus Plasmodium: P. falciparum, P. vivax, P. ovale, or P. malariae. All species are transmitted by the bite of an infected female Anopheles mosquito. Occasionally, transmission occurs by blood transfusion or congenitally from mother to fetus. Although malaria can be a fatal disease, illness and death from malaria are largely preventable.

Occurrence

Malaria is a major international public health problem, causing 300–500 million infections worldwide and approximately 1 million deaths annually. Information about malaria risk in specific countries (Yellow Fever Vaccine Requirements and Information on Malaria Risk and Prophylaxis, by Country) is derived from various sources, including the World Health Organization. The information presented herein was accurate at the time of publication; however, factors that can vary from year to year, such as local weather conditions, mosquito vector density, and prevalence of infection, can have a marked effect on local malaria transmission patterns. Updated information may be found on the CDC Travelers’ Health website: http://www.cdc.gov/travel.

Malaria transmission occurs in large areas of Central and South America, Hispaniola, Africa, Asia (including the Indian Subcontinent, Southeast Asia, and the Middle East), Eastern Europe, and the South Pacific).

Map 3–4. Malaria-endemic countries in the Americas, 2002. View enlarged map If risk exists in any area of a country the entire country is shaded accordingly. Please refer to Yellow Fever Vaccine Requirements and Information on Malaria Risk and Prophylaxis, by Country for detailed risk and recommended prophylaxis information.

The estimated risk for a traveler’s acquiring malaria differs markedly from area to area. This variability is a function of the intensity of transmission within the various regions and of the itinerary and time and type of travel. From 1985 through 2001, 10,100 cases of malaria among U.S. civilians were reported to CDC. Of these, 5,849 (58%) were acquired in sub-Saharan Africa; 1,862 (18%) in Asia; 1,634 (16%) in the Caribbean and Central or South America; and 755 (7%) in other parts of the world. During this period, 70 fatal malaria infections occurred among U.S. civilians; 66 (94%) were caused by P. falciparum, of which 47 (71%) were acquired in sub-Saharan Africa.

Map 3–5. Malaria-endemic countries in Africa, the Middle East, Asia, and the South Pacific, 2002 View enlarged map If risk exists in any area of a country the entire country is shaded accordingly. Please refer to Yellow Fever Vaccine Requirements and Information on Malaria Risk and Prophylaxis, by Country for detailed risk and recommended prophylaxis information.

Thus, most imported P. falciparum malaria among American travelers was acquired in Africa south of the Sahara, even though only 483,000 U.S. residents traveled to countries in that region in 2000. In contrast, that year 27 million U.S. residents traveled from the United States to other countries where malaria is endemic (including 19 million travelers to Mexico). This disparity in the risk for acquiring malaria reflects the fact that the predominant species of malaria transmitted in sub-Saharan Africa is P. falciparum, that malaria transmission is generally higher in Africa than in other parts of the world, and that malaria is often transmitted in urban areas as well as rural areas in sub-Saharan Africa. In contrast, malaria transmission is generally lower in Asia and South America, a larger proportion of the malaria is P. vivax, and most urban areas do not have malaria transmission.

Estimating the risk for infection for various types of travelers is difficult and can be substantially different even for persons who travel or reside temporarily in the same general areas within a country. For example, travelers staying in air-conditioned hotels may be at lower risk than backpackers or adventure travelers. Similarly, long-term residents living in screened and air-conditioned housing are less likely to be exposed than are persons living without such amenities, such as Peace Corps volunteers.

Persons who have been in a malaria risk area, either during daytime or nighttime hours, are not allowed to donate blood for a period of time after returning from the malarious area. Persons who are residents of nonmalarious countries are not allowed to donate blood for 1 year after they have returned from a malarious area. Persons who are residents of malarious countries are not allowed to donate blood for 3 years after leaving a malarious area. Persons who have had malaria are not allowed to donate blood for 3 years after treatment for malaria.

Clinical Presentation

Malaria is characterized by fever and influenzalike symptoms, including chills, headache, myalgias, and malaise; these symptoms can occur at intervals. Malaria may be associated with anemia and jaundice, and P. falciparum infections can cause seizures, mental confusion, kidney failure, coma, and death. Malaria symptoms can develop as early as 6 days after initial exposure in a malaria-endemic area and as late as several months after departure from a malarious area, after chemoprophylaxis has been terminated.

Prevention

No vaccine is currently available. Taking an appropriate drug regimen and using antimosquito measures will help prevent malaria. Travelers should be informed that, regardless of methods employed, they are still at risk for contracting malaria.

Personal Protection Measures

Because of the nocturnal feeding habits of Anopheles mosquitoes, malaria transmission occurs primarily between dusk and dawn. Travelers should be advised to take protective measures to reduce contact with mosquitoes, especially during these hours. Such measures include remaining in well-screened areas, using mosquito nets, and wearing clothes that cover most of the body. Additionally, travelers should be advised to purchase insect repellent for use on exposed skin. The most effective repellent against a wide range of vectors is DEET (N,N-diethylmetatoluamide), an ingredient in many commercially available insect repellents. The actual concentration of DEET varies widely among repellents. DEET formulations as high as 50% are recommended for both adults and children >2 months of age. (See Protection against Mosquitoes and Other Arthropod Vectors.)

Travelers not staying in well-screened or air-conditioned rooms should be advised to use a pyrethroid-containing flying-insect spray in living and sleeping areas during evening and nighttime hours. They should take additional precautions, including sleeping under insecticide-treated bed nets. In the United States, permethrin (Permanone) is available as a liquid or spray. Overseas, either permethrin or another insecticide, deltamethrin, is available and may be sprayed on bed nets and clothing for additional protection against mosquitoes. Bed nets are more effective if they are treated with permethrin or deltamethrin insecticide; bed nets may be purchased that have already been treated with insecticide.

Chemoprophylaxis

Chemoprophylaxis is a broad term comprising multiple strategies for the prevention of malaria by using medications. Primary prophylaxis is the strategy that uses medications prior to, during, and after the exposure period to prevent the initial infection. Terminal prophylaxis is the strategy that uses medications toward the end of the exposure period (or immediately thereafter) to prevent relapses or delayed-onset clinical presentations of malaria caused by P. vivax or P. ovale.

In choosing an appropriate chemoprophylactic regimen before travel, the traveler and the health-care provider should consider several factors. The travel itinerary should be reviewed in detail and compared with the information on areas of risk in a given country (Yellow Fever Vaccine Requirements and Information on Malaria Risk and Prophylaxis, by Country) to determine whether the traveler will actually be at risk for acquiring malaria. Whether the traveler will be at risk for acquiring drug-resistant P. falciparum malaria should also be determined. Resistance to antimalarial drugs has developed in many regions of the world. Health-care providers should consult the latest information on resistance patterns before prescribing prophylaxis for their patients. (See section "Malaria Hotline" below for details about accessing this information from CDC.)

The resistance of P. falciparum to chloroquine has been confirmed in all areas with P. falciparum malaria except the Dominican Republic, Haiti, Central America west of the former Panama Canal Zone, Egypt, and some countries in the Middle East. In addition, resistance to Fansidar is widespread in the Amazon River Basin area of South America, much of Southeast Asia, other parts of Asia, and, increasingly, in large parts of Africa. Resistance to mefloquine has been confirmed on the borders of Thailand with Burma (Myanmar) and Cambodia, in the western provinces of Cambodia, and in the eastern states of Burma (Myanmar).

Tolerability

Malaria chemoprophylaxis with mefloquine or chloroquine should begin 1–2 weeks before travel to malarious areas; prophylaxis with doxycycline and atovaquone/proguanil can begin 1–2 days before travel. Beginning the drug before travel allows the antimalarial to be in the blood before exposure to the malaria parasite. Chemoprophylaxis can be started earlier if there are particular concerns about tolerating one of the medications. Starting the medication 3–4 weeks in advance allows potential adverse events to occur prior to travel. Should unacceptable side effects develop, there would be a greater window of opportunity to change the medication before the traveler’s departure.

The drugs used for antimalarial chemoprophylaxis are generally well tolerated. However, side effects can occur. Minor side effects usually do not require stopping the drug. Travelers who have serious side effects should see a health-care provider. See the section below on “Adverse Reactions and Contraindications” for more detail on safety and tolerability of the drugs used for malaria prevention. In addition, the health-care provider should establish whether the traveler has previously experienced an allergic or other reaction to one of the antimalarial drugs of choice and whether medical care will be readily accessible during travel.

General Recommendations for Primary Prophylaxis

Chemoprophylaxis should continue during travel in the malarious areas and after leaving the malarious areas (4 weeks after travel for chloroquine, mefloquine, and doxycycline, and 7 days after travel for atovaquone/proguanil). Drugs with longer half-lives, which are taken weekly, offer the advantage of a wider margin of error if the traveler is late with a dose than drugs with short half-lives, which are taken daily. For example, if a traveler is 1–2 days late with a weekly drug, prophylactic blood levels can remain adequate; if the traveler is 1–2 days late with a daily drug, protective blood levels are less likely to be maintained.

Travel to Areas without Chloroquine-Resistant P. falciparum

For travel to areas of risk where chloroquine-resistant P. falciparum has NOT been reported, once-a-week use of chloroquine alone should be recommended for primary prophylaxis. Persons who experience uncomfortable side effects after taking chloroquine may tolerate the drug better by taking it with meals. As an alternative, the related compound hydroxychloroquine sulfate may be better tolerated. Travelers unable to take chloroquine or hydroxychloroquine should take atovaquone/proguanil, doxycycline, or mefloquine; these antimalarials are also effective against chloroquine-sensitive parasites.

Chloroquine prophylaxis should begin 1–2 weeks before travel to malarious areas. It should be continued once a week, on the same day of the week, during travel in malarious areas and for 4 weeks after a traveler leaves such areas. (See Table 3–9 for recommended dosages.)

Travel to Areas with Chloroquine-Resistant P. falciparum

For travel to areas of risk where chloroquine-resistant P. falciparum exists, three efficacious options exist, listed in alphabetical order below. In addition, there are new recommendations for the use of primaquine for primary prophylaxis in special situations.

Atovaquone/proguanil (Malarone). Atovaquone/proguanil is a fixed combination of the two drugs, atovaquone and proguanil. Atovaquone/proguanil primary prophylaxis should begin 1–2 days before travel to malarious areas and should be taken daily, at the same time each day, while in the malarious area and daily for 7 days after leaving such areas. (See Table 3–9 for recommended dosages.)

Doxycycline (Many brand names and generic). Doxycycline primary prophylaxis should begin 1–2 days before travel to malarious areas. It should be continued once a day, at the same time each day, during travel in malarious areas and daily for 4 weeks after the traveler leaves such areas. We have insufficient data that related compounds such as minocycline (which is commonly prescribed for the treatment of acne) are equally effective against malaria. Persons on a long-term regimen of minocycline who are in need of malaria prophylaxis should stop taking minocycline 1–2 days prior to travel and start doxycycline instead. The minocycline can be restarted after the full course of doxycycline is completed. (See Table 3–9 for recommended dosages.)

Either doxycycline or atovaquone/proguanil (see above) can be used by travelers to areas with mefloquine-resistant strains of P. falciparum (the borders of Thailand with Burma and Cambodia, western Cambodia, and eastern Burma–see Map 3-6).

Map 3–6. Mefloquine-resistant malaria View enlarged map Note: Zones with mefloquine-resistant malaria are known to be expanding. Please check the CDC Travelers’ Health website at http://www.cdc.gov/travel for updates.

Mefloquine (Lariam and generic). Mefloquine primary prophylaxis should begin 1–2 weeks before travel to malarious areas. It should be continued once a week, on the same day of the week, during travel in malarious areas and for 4 weeks after a traveler leaves such areas. (See Table 3–9 for recommended dosages.)

NOTE: In rare instances and after consultation with malaria experts such as those available through the CDC Malaria Hotline (770-488-7788), primaquine may be used for primary prophylaxis for travel to areas with or without chloroquine-resistant P. falciparum. This use should generally be reserved for travelers unable to take any of the other chemoprophylaxis regimens recommended for the region of travel. The traveler must have a documented level of G6PD in the normal range prior to being prescribed primaquine. Primaquine primary prophylaxis should begin 1–2 days before travel to malarious areas, taken daily at the same time each day, while in the malarious area, and daily for 7 days after leaving such areas. (See Table 3–9 for recommended dosages.)

CDC no longer recommends chloroquine/proguanil as a preventive option for persons traveling to areas with chloroquine-resistant P. falciparum.

Prevention of Relapses of P. vivax and P. ovale:
Terminal Prophylaxis with Primaquine

P. vivax and P. ovale parasites can persist in the liver and cause relapses for as long as 4 years or more after routine chemoprophylaxis is discontinued. Travelers to malarious areas should be alerted to this risk and, if they have malaria symptoms after leaving a malarious area, they should be advised to report their travel history and the possibility of malaria to a physician as soon as possible.

Primaquine terminal prophylaxis decreases the risk of relapses by acting against the liver stages of P. vivax or P. ovale. Primaquine terminal prophylaxis is administered for 14 days after the traveler has left a malaria-endemic area. When chloroquine, doxycycline, or mefloquine is used for primary prophylaxis, primaquine is usually taken during the last 2 weeks of postexposure prophylaxis. When atovaquone/proguanil is used for primary prophylaxis, primaquine may be taken either during the final 7 days of atovaquone/ proguanil and then for an additional 7 days, or for 14 days after atovaquone/proguanil is completed. Note that the recommended dose of primaquine for terminal prophylaxis has been increased from 15 mg to 30 mg for adults and from 0.3 mg/kg to 0.6 mg/kg for children. (See Table 3–9 for additional details.)

Because most malarious areas of the world (except Haiti and the Dominican Republic) have at least one species of relapsing malaria, travelers to these areas have some risk for acquiring either P. vivax or P. ovale, although the actual risk for an individual traveler is difficult to define. Terminal prophylaxis with primaquine for prevention of relapses is generally indicated only for persons who have had prolonged exposure in malaria-endemic areas (e.g., missionaries and Peace Corps volunteers). Most persons can tolerate the standard regimen of primaquine; an exception is persons who are deficient in G6PD. (See “Adverse Reactions and Contraindications” and Table 3–9 for recommended dosages.)

Chemoprophylaxis for Infants, Children, and Adolescents

Infants, children, and adolescents of any age can contract malaria. Therefore, children traveling to malaria-risk areas should take an antimalarial drug. In the United States, antimalarial drugs are available only in tablet form and may taste quite bitter. Pediatric dosages should be carefully calculated according to body weight, but should never exceed adult dosage. Pharmacists can pulverize tablets and prepare gelatin capsules for each measured dose. Advise parents to prepare the child’s dose of medication by breaking open the gelatin capsule and mixing the drug with something sweet, such as applesauce, chocolate syrup, or jelly. Giving the dose on a full stomach may minimize stomach upset and vomiting.

Infants, Children, and Adolescents Traveling to Areas without Chloroquine-Resistant P. falciparum

Chloroquine is the drug of choice for children traveling to areas without chloroquine-resistant P. falciparum. Travelers staying an extended length of time in a malaria-risk area may find it more convenient to purchase chloroquine as a suspension, which is widely available overseas. Physicians should calculate the dose and volume to be administered based on body weight, because the concentration of chloroquine base varies in different suspensions.

Infants, Children, and Adolescents Traveling to Areas with Chloroquine-Resistant P. falciparum

Mefloquine is an option for use in infants and children of all ages and weights who are traveling to areas with chloroquine-resistant P. falciparum. Doxycycline may be used for children 8 years of age or more. Atovaquone/proguanil may be used for infants and children weighing 11 kg or more (25 lbs or more) can be given for prophylaxis. At this time, insufficient data are available on the safety and efficacy of atovaquone/proguanil for prevention of malaria in children weighing <11 kg (<25 lbs). Atovaquone/proguanil is available in pediatric tablet form; dosage is based on weight. Pediatric dosing regimens are contained in Table 3–9; additional information on atovaquone/proguanil dosing is found in Table 3–10.

Chemoprophylaxis during Pregnancy

Malaria infection in pregnant women can be more severe than in nonpregnant women. Malaria can increase the risk for adverse pregnancy outcomes, including prematurity, abortion, and stillbirth. For these reasons and because no chemoprophylactic regimen is completely effective, women who are pregnant or likely to become pregnant should be advised to avoid travel to areas with malaria transmission if possible. (Also see Malaria during Pregnancy). If travel to a malarious area cannot be deferred, use of an effective chemoprophylaxis regimen is essential.

Travel during Pregnancy to Areas without Chloroquine-Resistant P. falciparum

Pregnant women traveling to areas where drug-resistant P. falciparum has not been reported may take chloroquine prophylaxis. Chloroquine has not been found to have any harmful effects on the fetus when used in the recommended doses for malaria prophylaxis; therefore, pregnancy is not a contraindication for malaria prophylaxis with chloroquine phosphate or hydroxychloroquine sulfate.

Travel during Pregnancy to Areas with Chloroquine-Resistant P. falciparum

Mefloquine is currently the only medication recommended for malaria chemoprophylaxis during pregnancy. A review of mefloquine use in pregnancy from clinical trials and reports of inadvertent use of mefloquine during pregnancy suggest that its use at prophylactic doses during the second and third trimesters of pregnancy is not associated with adverse fetal or pregnancy outcomes. More limited data suggest it is also safe to use during the first trimester.

Because of insufficient data regarding the use of atovaquone/proguanil during pregnancy, it is not currently recommended for the prevention of malaria in pregnant women. Doxycycline is contraindicated for malaria prophylaxis during pregnancy because of the risk of adverse effects of tetracycline, a related drug, on the fetus, which include discoloration and dysplasia of the teeth and inhibition of bone growth. Primaquine should not be used during pregnancy because the drug may be passed transplacentally to a glucose-6-phosphate dehydrogenase (G6PD)-deficient fetus and cause hemolytic anemia in utero. Health-care professionals who require additional assistance with the management of pregnant travelers who are unable to take mefloquine chemoprophylaxis should call the CDC Malaria Hotline (770-488-7788).

Antimalarial Drugs during Breast-Feeding

Data are available for some antimalarial agents on the amount of drug excreted in breast milk of lactating women. Very small amounts of chloroquine and mefloquine are excreted in the breast milk of lactating women. The amount of drug transferred is not thought to be harmful to a nursing infant. Because the quantity of antimalarials transferred in breast milk is insufficient to provide adequate protection against malaria, infants who require chemoprophylaxis must receive the recommended dosages of antimalarials listed in Table 3–9.

Although there are very limited data about the use of doxycycline in lactating women, most experts consider the theoretical possibility of adverse events to be remote.

No information is available on the amount of primaquine that enters human breast milk; the infant should be tested for G6PD deficiency before primaquine is given to a woman who is breast-feeding.

It is not known whether atovaquone is excreted in human milk. Proguanil is excreted in human milk in small quantities. Based on experience with other antimalarial drugs, the quantity of drug transferred in breast milk is insufficient to provide adequate protection against malaria for the infant. Because data are not yet available on the safety and efficacy of atovaquone/proguanil in infants weighing <11 kg (24 lbs), it is not currently recommended for the prevention of malaria in women breast-feeding infants weighing <11 kg. (Atovaquone/proguanil may be used for the treatment of malaria when the potential benefit outweighs the potential risk to the infant, e.g., treating a breast-feeding woman who has acquired P. falciparum malaria in an area of multidrug-resistant strains and who cannot tolerate other treatment options).

Adverse Reactions and Contraindications

Following is a summary of the frequent or serious side effects of recommended antimalarial drugs. In addition, physicians should review the prescribing information in standard pharmaceutical reference texts and in the manufacturers’ package inserts.

Atovaquone/Proguanil

The most common adverse effects reported in persons using atovaquone/proguanil for prophylaxis or treatment are abdominal pain, nausea, vomiting, and headache. Atovaquone/proguanil should not be used in children <11 kg, pregnant women, women breast-feeding infants weighing <11 kg, or patients with severe renal impairment (creatinine clearance <30 mL/min).

Chloroquine and Hydroxychloroquine Sulfate

Side effects that can occur include gastrointestinal disturbance, headache, dizziness, blurred vision, insomnia, and pruritus, but generally these effects do not require that the drug be discontinued. High doses of chloroquine, such as those used to treat rheumatoid arthritis, have been associated with retinopathy; this serious side effect appears to be extremely unlikely when chloroquine is used for routine weekly malaria prophylaxis. Chloroquine and related compounds have been reported to exacerbate psoriasis.

Doxycycline

Doxycycline can cause photosensitivity, usually manifested as an exaggerated sunburn reaction. The risk of such a reaction can be minimized by avoiding prolonged, direct exposure to the sun and by using sunscreens that absorb long-wave UVA radiation. In addition, doxycycline use is associated with an increased frequency of Candida vaginitis. Gastrointestinal side effects (nausea or vomiting) may be minimized by taking the drug with a meal. To reduce the risk of esophagitis, travelers should be advised not to take doxycycline before going to bed. Doxycycline is contraindicated in persons with an allergy to tetracyclines, during pregnancy, and in infants and children <8 years of age. Vaccination with the oral typhoid vaccine Ty21a should be delayed for >24 hours after taking a dose of doxycycline. (See Travelers’ Health Information on Typhoid.)

Mefloquine

Mefloquine has been associated with rare serious adverse reactions (e.g., psychoses or seizures) at prophylactic doses; these reactions are more frequent with the higher doses used for treatment. Other side effects that occur with prophylactic doses include gastrointestinal disturbance, headache, insomnia, abnormal dreams, visual disturbances, depression, anxiety disorder, and dizziness.

Mefloquine is contraindicated for use by travelers with a known hypersensitivity to mefloquine and in persons with active depression or with a history of psychosis or seizures. It should be used with caution in persons with psychiatric disturbances. A review of available data suggests that mefloquine may be used in persons concurrently on beta blockers, if they have no underlying arrhythmia. However, mefloquine is not recommended for persons with cardiac conduction abnormalities.

Primaquine

Primaquine can cause fatal hemolysis in G6PD-deficient persons. Before primaquine is used, G6PD deficiency MUST be ruled out by appropriate laboratory testing.

Medications Acquired Overseas

The medications we recommend for chemoprophylaxis and treatment of malaria may also be available at overseas destinations. However, combinations of these medications and additional drugs that are not recommended may be commonly used and prescribed in other countries. Travelers should be strongly discouraged from obtaining chemoprophylactic medications while abroad. Medications purchased overseas may be ineffective because of substandard manufacturing practices. These treatments may also be dangerous, counterfeit, or contain contaminants. Additional information can be found in a Food and Drug Administration document entitled "Purchasing Medications Outside the United States". This document can be found at: http://www.fda.gov/ora/import/purchasing_medications.htm.

Medications that are not used in the United States, such as halofantrine (Halfan), are widely available overseas. Halofantrine is not recommended because of cardiac adverse events, including deaths, which have been documented following treatment doses. These adverse events have occurred in persons with and without preexisting cardiac problems and both in the presence and absence of other antimalarial drugs (e.g., mefloquine). Health-care providers should caution travelers to avoid using medications that are not recommended unless they have been diagnosed with life-threatening malaria and no other options are available.

Changing Medications During Chemoprophylaxis as a Result of Side Effects

The medications recommended for prophylaxis against malaria have different modes of action that affect the parasite at different stages of the life cycle. Thus, if the medication needs to be changed because of side effects prior to the completion of a full course, there are some special considerations. If a traveler starts prophylaxis with a medication such as mefloquine or doxycycline and then changes to atovaquone/proguanil during or after travel, the standard duration of therapy would be insufficient. The atovaquone/proguanil should be continued for 4 weeks after the switch or 1 week after returning, whichever is longer. Health-care professionals who require additional assistance with the management of travelers who need to change medications during prophylaxis should call the CDC Malaria Hotline (770-488-7788).

Treatment

Specific treatment with antimalarial drugs is available. Travelers should be advised that malaria can be treated effectively early in the course of the disease but that delay of appropriate therapy can have serious or even fatal consequences. Travelers who have symptoms of malaria should be advised to seek prompt medical evaluation, including thick and thin blood smears, as soon as possible. If possible, it is advisable to consult with a provider with specialized travel/tropical medicine expertise or with an infectious disease physician.

Self-Treatment

CDC recommends the use of malaria prophylaxis for travel to malarious areas. However, travelers who elect not to take prophylaxis, who do not choose an optimal drug regimen (e.g., chloroquine in an area with chloroquine-resistant P. falciparum) or who require a less than optimal drug regimen are at greater risk for acquiring malaria and needing prompt treatment. Long-term travelers who are taking effective prophylaxis but who will be in very remote areas may decide, in consultation with their health-care provider, to take along a dose of antimalarial medication for self-treatment. Travelers should be advised to take their presumptive self-treatment promptly if they have a fever, chills, or other influenzalike illness and if professional medical care is not available within 24 hours. Travelers should be advised that this self-treatment of a possible malarial infection is only a temporary measure and that prompt medical evaluation is imperative.

Recommendations for Presumptive Self-Treatment

Atovaquone/proguanil may be used for presumptive self-treatment for travelers NOT taking atovaquone/proguanil for prophylaxis. The CDC Malaria Branch (Malaria Hotline 770-488-7788) can provide consultation to health-care providers on other potential options for self-treatment if atovaquone/proguanil cannot be used.

Malaria Hotline

Detailed recommendations for the prevention of malaria are available from CDC 24 hours a day from the voice information service (1-877-FYI-TRIP; 1-877-394-8747), the fax information service (1-888-232-3299), or the Internet at http://www.cdc.gov/travel.

Health-care professionals who require assistance with the diagnosis or treatment of malaria should call the CDC Malaria Hotline (770-488-7788) from 8:00 a.m. to 4:30 p.m. Eastern time. After hours or on weekends and holidays, health-care providers requiring assistance should call the CDC Emergency Operation Center at 770-488-7100 and ask the operator to page the person on call for the Malaria Epidemiology Branch.

For more information about malaria, see the CDC Malaria site at http://www.cdc.gov/malaria.

— Paul Arguin, Ann Barber, Phyllis Kozarsky, Sonja Mali, Robert Newman, Monica Parise, Susanna Partridge