Malaria

Information on previous exposure can be obtained from the refugees themselves, or more detailed information on previous exposure to specific species can be obtained through international channels via WHO.

Within a camp, the proportion of fever illness attributable to malaria at a particular time can be determined by obtaining thick and thin blood smears from a sample of consecutive clinic patients with a history of recent fever (e.g., 50 children less than 5 years of age). The malaria infection prevalence rate among these patients can then be compared with a control group that is free of the signs and symptoms of malaria.

Laboratory examination will determine whether malaria illness is caused by Plasmodium falciparum or Plasmodium vivax.

Control of Transmission

Personal protection. The use of protective clothing, insecticide-impregnated bed nets, and insect repellents will help limit human exposure to malaria-infected mosquitoes.

Residual insecticides. Periodic spraying of the inside surfaces of permanent dwellings may reduce transmission. The use of residual insecticides, however, may be toxic to those involved in spraying and can also be detrimental to the environment. Spraying can be expensive and time consuming. Careful consideration should be given to the technical aspects of spraying, local vector behavior and susceptibility, personnel training, safety, and community motivation before undertaking such a program.

Source reduction. The elimination of breeding sites by draining or filling may reduce the density of vectors in the area. Knowledge of the local vectors is essential to ensure that source reduction efforts are effectively targeted.

Ultra low-volume insecticide spraying. Adult mosquitoes may be killed through frequent fogging with nonresidual insecticides. Fogging is generally repeated on a daily basis.

Gametocidal drug use. Gametocidal drugs (e.g., primaquine) are not generally recommended for use in refugee camps.

Selection of control strategies will depend upon the local epidemiologic factors, availability of resources, and environmental and cultural factors.

Case Management

Diagnosis. If possible, a thick blood smear and Giemsa stain should be the basis for the diagnosis of malaria. These smears will also provide the basis for transmission surveillance in camps or geographic areas. If the patient load exceeds the capability of the laboratory to perform thick smears on all suspected cases, a system of microscopic diagnosis for a percentage of suspected cases should be established. When diagnoses are made by locally trained microscopists in small field laboratories, a randomly selected sample of both positive and negative slides should be sent to a reference laboratory for verification in order to maintain quality control.

When laboratory facilities are not available, clinical symptoms (paroxysmal fever, chills, sweats, and headache) and signs (measured fever) are the best predictors of malaria infection. In situations in which year-round high malaria endemicity has been established, all episodes of fever illness can be assumed to be caused by Plasmodium falciparum. However, health workers should bear in mind other causes of fever, including pneumonia, ALRI, or meningitis. In areas where transmission is highly seasonal, surveys should be conducted each year at the beginning of the high transmission season.

The presence of Plasmodium on blood smears does not prove that malaria is the cause of febrile illness, even in areas where malaria is highly prevalent. Other causes should be considered and ruled out.

Treatment with chemotherapy. In areas without chloroquine resistance, the oral regimen of chloroquine usually employed in the treatment of uncomplicated attacks of malaria is as follows:

• Adults: A total dose of 1,500 mg chloroquine (approximately 25 mg/kg body weight) should be given during a 3-day period. This can be given as 600 mg, 600 mg, and 300 mg at 0, 24, and 48 hours, respectively.
• Pregnant women: Pregnant women with malaria should be treated aggressively using the regimen for adults. Chloroquine is safe during pregnancy. (Quinine is also safe although pregnant women receiving IV-administered quinine should be monitored carefully for hypoglycemia.)
• Children: A total dose of 25 mg/kg body weight chloroquine should be given during a 3-day period. This can be administered as 10 mg/kg, 10 mg/kg, and 5 mg/kg body weight at 0, 24 and 48 hours, respectively.

• Adults: 15 mg daily for 14 days.
• Children: 0.3 mg/kg/day.

When laboratory analysis is performed, the first dose of chloroquine should be administered when the blood smear is taken. The patient should be instructed to return the second day for the results of the smear. If the smear is positive, chemotherapy should be continued. If the smear is negative and the patient remains febrile, other causes of fever should be identified.

If supervised therapy during a 3-day period is not possible, the first dose of chloroquine should be given under supervision and the additional doses may be given to the patient with appropriate instructions.

Patients who remain symptomatic longer than 3 days into therapy should have a repeat thick smear examined. Alternative therapy should be instituted if the degree of parasitemia has not diminished markedly by this time.

In areas with chloroquine resistance, treatment of patients may be the same as in areas of chloroquine-sensitive malaria; or may include an alternative first-line drug. Additional care in the follow-up of patients is required.

• If the patient continues to have symptoms of malaria after 48-72 hours from the start of recommended chloroquine treatment, the patient should be treated with a second-line drug.
• The choice of an alternative drug depends on the availability of the drugs and the relative sensitivity of the parasites. Possible alternative drugs include sulfa drugs in combination with pyrimethamine (Fansidar, Maloprim), tetracycline, quinine, and newer drugs such as mefloquine. Use of alternative drugs should be consistent with national malaria control policies in the host country.

Children with high fevers should be frequently sponged with tepid water. Patients should increase their intake of fluids as the febrile illness will most likely be accompanied by mild dehydration. Patients with signs of moderate dehydration should be given ORS.

Chemoprophylaxis

• Children less than 5 years of age, especially those suffering from malnutrition, anemia, or other debilitating diseases.
• Pregnant women.
• Other groups that are at increased risk for complications of malaria illness due to compromised health status.

• At-risk persons can be readily identified and assembled.
• Follow-up can be assured.
• Sufficient personnel and medication are available to ensure regular administration of services.
• The parasite is known to be generally sensitive to the drug used.

Expatriates working in an endemic area should be on weekly chloroquine (300 mg chloroquine base) during the entire period of exposure and for an additional 6 weeks after leaving the area. In areas where chloroquine resistance is documented, prophylaxis with mefloquine is recommended (250 mg weekly dose).

Severe malaria

• Severe anemia.
• Hemoglobinuria, oliguria, or anuria.
• Hypotension and respiratory distress.
• Jaundice.
• Hemorrhagic diatheses.
• Cerebral malaria.

Management of severe malaria. The following guidelines for the management of severe malaria are based upon those prepared by the MOH in Malawi.

Outpatient setting. If severe malaria is diagnosed in an outpatient setting, the patient should be referred for hospitalization. However, treatment should begin immediately and not be delayed until the patient has been transferred.

If the patient can swallow, sulfadoxine-pyrimethamine (SP) tablets (500 mg-25 mg) should be administered orally in the following doses according to the patient's age.

• less than 3 years old: 1/2 tablet
• 4-8 years old: 1 tablet
• 9-14 years old: 2 tablets
• greater than 14 years old: 3 tablets

If the patient cannot swallow or is vomiting repeatedly, an IM injection of quinine dihydrochloride (10 mg/kg) should be administered. This can be repeated every 4 hours for two additional doses, and every 8 hours thereafter if a long delay is anticipated for transport of the patient to a hospital.

The patient's fever should be reduced by sponging with lukewarm water or by using paracetamol or aspirin. Patients should be given ORS. In a patient who cannot drink, administer 20 mL/kg ORS with one teaspoon of glucose powder via naso-gastric tube every 4 hours.

If convulsions occur, administer 0.2 mL/kg paraldehyde by IM injection. If convulsions recur, repeat the treatment. If convulsions persist, give the patient a phenobarbitone 10-mg/kg IM injection.

In a child with altered consciousness or repeated convulsions, the physician should perform a lumbar puncture if possible. If the CSF is cloudy, treatment for meningococcal meningitis is indicated and anti-malarial treatment should be discontinued. If a lumbar puncture cannot be performed, treatment for meningitis should be administered while continuing treatment for malaria.

Inpatient setting. The following tests should be performed immediately upon admission: thick blood film, hemoglobin, blood glucose, and lumbar puncture. If hemoglobin is below 4 g/dL, blood grouping and cross-matching should be done.

If the patient can swallow, give oral SP as described above. If the patient cannot swallow or has persistent vomiting, give IV-administered quinine as follows:

• An initial dose of 20 mg(salt)/kg body weight is injected into 10 mL/kg 5% dextrose (half-strength Darrow's solution) and infused during a 3-hour period. (If the patient has already received quinine before admission, the initial dose should be 10 mg/kg.)
• Subsequent doses of 10 mg/kg should be repeated as above every 12 hours. In between doses of quinine, the IV fluid (10 mL/kg during a 3-hour period) should be continued. Patients should be switched to oral medications as soon as their conditions allow.

• Care in the administration of fluid therapy is required, since fluid overload can precipitate pulmonary edema or adult respiratory distress syndrome (ARDS), which can worsen cerebral edema.
• The IV fluid of choice is 5% dextrose with 1/2 normal saline, since this mixture provides dextrose to prevent hypoglycemia and less salt to leak into pulmonary and cerebral tissues. Alternative IV fluids should be considered if this is unavailable.

Blood transfusion is indicated when Hb less than 4 g/dL, or Hb less than 6 g/dL is detected and the patient has signs of heart failure (i.e., dyspnea, enlarging liver, gallop rhythm).

The administration of steroids has an adverse effect on outcome in cerebral malaria. Therefore, steroids are no longer recommended.

Anemia

For some patients (especially children), blood transfusion may be lifesaving. Recent studies indicate that blood transfusion should be given for Hb less than 4 g/dL or Hb less than 6 g/dL in the presence of symptoms of respiratory distress. Because of the potential for HIV or hepatitis B transmission, blood transfusion should be reserved for medical emergencies for which no alternative treatment exists. Facilities for screening blood for HIV antibodies are rare in refugee camps. Whenever feasible, patients requiring transfusion should be transferred to hospitals where such facilities exist.

The anemia of malaria is not associated with iron loss, and replacement is helpful only if a coexisting iron deficiency exists. Folic acid replacement may be helpful during the recovery period when rapid erythrocyte replacement occurs.

Renal failure

In the presence of oliguria, a fluid challenge followed by furosemide injection can help to differentiate acute renal failure from prerenal causes. If renal failure is demonstrated, fluid intake must be limited to daily replacement of insensible loss plus urine/vomitus volume in the previous 24 hours. Protein intake should be limited to less than 30 mg/day, and all drug doses should be adjusted for renal failure.

Selected Reading

Ministry of Health. Malawi guidelines for the management of malaria. Malawi, October 1991.

CDC. Steketee RW, Campbell CC. Control of malaria among refugees and displaced persons. Atlanta, GA:1988 (unpublished).

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