Acute PlasmodiumInfection Promotes Interferon-Gamma-Dependent Resistance to Ebola Virus Infection

During the 2013–2016 Ebola virus (EBOV) epidemic, a significant number of patients admitted to Ebola treatment units were co-infected with Plasmodium falciparum,a predominant agent of malaria. However, there is no consensus on how malaria impacts EBOV infection. The effect of acute Plasmodiuminfection on EBOV challenge was investigated using mouse-adapted EBOV and a biosafety level 2 (BSL-2) model virus. We demonstrate that acute Plasmodiuminfection protects from lethal viral challenge, dependent upon interferon gamma (IFN-γ) elicited as a result of parasite infection. Plasmodium-infected mice lacking the IFN-γ receptor are not protected. Ex vivoincubation of naive human or mouse macrophages with sera from acutely parasitemic rodents or macaques programs a proinflammatory phenotype dependent on IFN-γ and renders cells resistant to EBOV infection. We conclude that acute Plasmodiuminfection can safeguard against EBOV by the production of protective IFN-γ. These findings have implications for anti-malaria therapies administered during episodic EBOV outbreaks in Africa.