Plasmodium Parasitemia Associated With Increased Survival in Ebola Virus-Infected Patients

Clin Infect Dis. 2016 Oct 15;63(8):1026-33. doi: 10.1093/cid/ciw452. Epub 2016 Aug 15.


Background: The ongoing Ebola outbreak in West Africa has resulted in 28 646 suspected, probable, and confirmed Ebola virus infections. Nevertheless, malaria remains a large public health burden in the region affected by the outbreak. A joint Centers for Disease Control and Prevention/National Institutes of Health diagnostic laboratory was established in Monrovia, Liberia, in August 2014, to provide laboratory diagnostics for Ebola virus.

Methods: All blood samples from suspected Ebola virus-infected patients admitted to the Médecins Sans Frontières ELWA3 Ebola treatment unit in Monrovia were tested by quantitative real-time polymerase chain reaction for the presence of Ebola virus and Plasmodium species RNA. Clinical outcome in laboratory-confirmed Ebola virus-infected patients was analyzed as a function of age, sex, Ebola viremia, and Plasmodium species parasitemia.

Results: The case fatality rate of 1182 patients with laboratory-confirmed Ebola virus infections was 52%. The probability of surviving decreased with increasing age and decreased with increasing Ebola viral load. Ebola virus-infected patients were 20% more likely to survive when Plasmodium species parasitemia was detected, even after controlling for Ebola viral load and age; those with the highest levels of parasitemia had a survival rate of 83%. This effect was independent of treatment with antimalarials, as this was provided to all patients. Moreover, treatment with antimalarials did not affect survival in the Ebola virus mouse model.

Conclusions: Plasmodium species parasitemia is associated with an increase in the probability of surviving Ebola virus infection. More research is needed to understand the molecular mechanism underlying this remarkable phenomenon and translate it into treatment options for Ebola virus infection.

Keywords: coinfection; ebolavirus; plasmodium; survival.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Animals
  • Child
  • Child, Preschool
  • Coinfection*
  • Disease Models, Animal
  • Ebolavirus* / genetics
  • Female
  • Hemorrhagic Fever, Ebola / complications*
  • Hemorrhagic Fever, Ebola / diagnosis
  • Hemorrhagic Fever, Ebola / epidemiology
  • Hemorrhagic Fever, Ebola / mortality*
  • Humans
  • Infant
  • Infant, Newborn
  • Malaria / complications*
  • Malaria / diagnosis
  • Malaria / epidemiology
  • Malaria / parasitology*
  • Male
  • Mice
  • Middle Aged
  • Parasite Load
  • Parasitemia*
  • Plasmodium / genetics
  • Survival Rate
  • Viral Load
  • Young Adult