Parvovirus B19 (B19V) infection causes fifth disease, a disease characterized by rashes to the face and other parts of the body that primarily affects children. However, adults can also develop fifth disease and it can lead to more severe conditions. Patients that are immunocompromised, such as those who are HIV infected, organ transplant recipients, and cancer patients, can be particularly susceptible to more severe outcomes from B19V infection. Infection can also cause anemia and in pregnant women, it can lead to hydrops fetalis.