Malaria, Ebola coinfection common in Sierra Leone

Patients in Ebola treatment units of Sierra Leone were often coinfected with malaria parasites, increasing mortality risk, a retrospective cohort study found.

“The 2014-2015 epidemic of Ebola virus disease in parts of west Africa was the largest ever recorded, with nearly 12,000 deaths,” Matthew Waxman, MD, an associate clinical professor in the department of emergency medicine, David Geffen School of Medicine at UCLA, and colleagues wrote. “Even before 2014, malaria overburdened a strained health system in Sierra Leone, accounting for nearly 30% of hospital admissions and half of outpatient visits. Despite the prevalence of malaria in countries at risk for Ebola virus disease outbreaks, little data exist pertaining to Ebola virus and malaria parasite coinfection.”

A total of 1,524 cases were treated at three centers for suspected Ebola infection between Dec. 1, 2014, and Oct. 15, 2015. Waxman and colleagues reported that 90% of those (n = 1,368) had available diagnostic data for both malaria and Ebola. Median age was 29 years, and 52% of patients (n = 715) were men. Of the cohort for whom data were available, 1,114 patients tested negative for Ebola; 33% of those (n = 365) tested positive for malaria.

Of the 254 patients who tested positive for Ebola, 53 (21%) also had malaria, the researchers reported. Patients with both infections had the highest mortality risk of any group in the study, with 66% (n = 35) dying, followed by Ebola alone (52%; n = 105 of 201). The mortality rate was increased in patients with both malaria and Ebola (adjusted HR = 9.36; 95% CI, 6.18-14.18) and those with Ebola but not malaria (HR = 5.97; 95% CI, 4.44-8.02) compared with patients who did not have either infection but was reduced in patients who had malaria but not Ebola (HR = 0.37; 95% CI, 0.2-1.23), according to Waxman and colleagues.

In an accompanying editorial, Moses B.F. Massaquoi, MD, MPH, and Stephen B. Kennedy, MD, MPH, both of the Partnership for research on Ebola Vaccines in Liberia, wrote that although Waxman and colleagues’ findings were consistent with those from a study in Guinea, they conflicted with data from a study in Liberia, which indicated that coinfection with malaria and Ebola was protective.

“Although WHO guidelines advocate for the administration of antimalarial drugs in Ebola treatment units, the validity of this recommendation is unlikely to be convincingly settled any time soon,” Massaquoi and Kennedy wrote. “With the misuse of nonprescribed antimalarial drugs in resource-limited settings, coupled with overburdened laboratory systems and inadequate numbers of health workers per patient, differential diagnoses and management of febrile illnesses will remain a crucial challenge in West Africa.” – by Andy Polhamus

Disclosure: Massaquoi and Kennedy report no relevant financial disclosures. The researchers report no relevant financial disclosures.