Malaria kills more than 400,000 people a year. 67% of those deaths are children under five. Some children get malaria, but they do not die. The reasons for this are not completely understood. Malaria is caused by the Plasmodium parasite, in particular Plasmodium falciparum. Co-infection of malaria with gammaherpesviruses, such as Epstein Barr Virus (EBV), is common in young children under five in countries where malaria is present. Data from children living in Cameroon in Central Africa shows that children who have EBV and malaria are more likely to be hospitalized due to malaria complications than children who do not have EBV. Antibodies are one of the main weapons the immune system uses to fight malaria. EBV antagonizes antibody production, possibly by induction of IL-10, a molecule that prevents B cells from producing antibodies. EBV induces IL-10 production in infected cells and can synthesize a homolog of IL-10. We hypothesize that the IL-10 induced during EBV infection results in lower antibody titres in children who are infected with both the virus and Plasmodium parasites that cause malaria. The first goal of this research is to identify which cell types produce IL-10. VertX reporter mice will be used to determine this in a mouse model of EBV-malaria co-infection. Once specific cell types are identified genetically modified mice will be used to observe what happens during co-infection when those cell types have the IL-10 gene knocked out.