Study quantifies mistreatment of malaria in Afghanistan

Plasmodium parasite infecting a
red blood cell; Credit: St. Jude
Children′s Research Hospital

There is substantial inaccuracy in the diagnosis and treatment of malaria in northern and eastern Afghanistan, according to a study published on bmj.com.

Global malaria treatment guidelines recommend that a patient receive antimalarial drugs only when a diagnostic test positively identifies malaria parasites in the patient’s blood.

In Africa, however, many patients are treated for malaria even when the parasite test is negative.

Toby Leslie, PhD, of the London School of Hygiene and Tropical Medicine in the UK, and his colleagues wanted to determine if this practice is also common in Afghanistan.

The team assessed the accuracy of malaria diagnosis and treatment for 2357 patients with suspected malaria who were treated at 22 clinics in northern and eastern Afghanistan. Some clinics used microscopic diagnosis, while others relied on clinical signs and symptoms to diagnose malaria.

The researchers collected blood sample slides for every patient, and each of these slides were read by two independent experts. The experts recorded whether a slide was positive or negative for malaria. And the researchers compared this reference result to the diagnosis made at the clinic and the treatment each patient received.

In clinics using clinical signs to diagnose malaria, 99% of patients with negative reference slides received a malaria drug, and 11% received an antibiotic.

In clinics using newly introduced microscopy, 37% of patients with a negative reference slide received a malaria drug, and 60% received an antibiotic. In clinics with established microscopy, 50.8% of patients with a negative reference slide received a malaria drug, and 27% received an antibiotic.

Dr Leslie and his colleagues said these results show that microscopy does not completely prevent the unnecessary use of antimalarials. In fact, both microscopy settings had a low specificity.

In the clinics with newly introduced microscopy, 20% of results were false-positives, and the specificity was 79.9%. In the clinics with established microscopy, 27.1% of results were false-positives, and the specificity was 72.9%.
 
However, the researchers argued that improper treatment of malaria is caused in equal parts by inaccurate diagnosis and by clinicians’ tendency to treat with malaria drugs even when a test result is negative, which results in a 40% to 50% loss of accuracy in treatment.

Dr Leslie and his colleagues also pointed out that these results are comparable to findings from Africa, which appears to confirm that inaccurate diagnosis and treatment of malaria is a worldwide problem.

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