Inclusion Criteria for health facility based study:  Category A: A sample of patients presenting to the health facility meeting this inclusion criteria will be enrolled:  • Persons ≥ 10 years of age who are malaria negative AND have undifferentiated acute fever at the time of presentation (≥ 37.5°C) or reported fever in the past 4 weeks.  Category B: A sample of patients presenting to the health facility meeting this inclusion criteria will be enrolled:  • Persons ≥ 10 years of age who are malaria positive AND have undifferentiated acute fever at the time of presentation (≥ 37.5°C) or reported fever in the past 4 weeks.  Category C: All patients at the health facility meeting these criteria will be enrolled in the study  Persons ≥ 10 years of age with:  • Unexplained bleeding with or without fever manifesting as either: Blood in vomitus, Bleeding from the gums, Bleeding from the nose, Bleeding in the eyes (red eyes), Non-menstrual genital bleeding, Bleeding from any other body site OR  • Infectious disease illness of unknown etiology requiring hospitalization. The illness should not be responding to antimalarials and/or antibiotics following 7 days of treatment  Inclusion Criteria for community cross sectional study:  Member of household 2 or more years of age.  Exclusion Criteria:  Those who do not consent or refuse written consent. If a participant is severely ill and has no next of kin to provide consent +/- witness on their behalf.  If a participant is known to have blood clotting disorders, allergies arising from injections, or if a participant has ever fainted during previous injections or blood collection