Phase 1 Challenge Study Using rDEN2delta30-7169 to Evaluate Host-Pathogen Interactions in Primary, Homotypic, and Heterotypic Dengue Virus Infection

Background: Dengue is a viral disease spread by mosquitoes. Most people bitten by mosquitoes carrying dengue viruses do not get sick, but severe cases can cause shock, internal bleeding, and death. There are no treatments for dengue. To develop treatments, researchers need to understand more about what dengue viruses do in the body. Objective: To infect healthy people with a mild dengue virus to study how their body responds. Eligibility: People ages 18 to 50 years with or without a history of dengue virus infection. Design: Participants will be screened. They will have a physical exam with blood tests. The tests will show whether they have ever been infected with dengue or related viruses in the past. At their first study visit, participants will receive an injection of dengue virus into the arm. The injected virus is weaker than the natural virus, so any symptoms should be milder. Participants will have a total of 11 study visits over 6 months; 8 of those visits will be in the first month. Blood will be drawn at each visit. Some visits will include ultrasound exams of their internal organs. They will discuss any symptoms they are having. Any rashes they develop may be photographed. Two procedures are optional: Participants may have up to 5 lymph node aspirations and 3 bone marrow biopsies during the study. For both procedures, a needle will be inserted into the tissues to draw out immune cells. Two more visits are optional: 1 visit up to 2 months before receiving the virus, for lymph node or bone marrow samples, and 1 about a year after for a blood draw.