B19 virus is distributed worldwide. The exact data on seroposi-tivity in population world over is not known. Approximately, 90% of adults older than 60 years are seropositive in the United States. Similar data from other parts of the world are lacking.
B19 virus infection is strictly a human disease. Humans are the only reservoir. Viruses are excreted in respiratory samples, which are the primary source of infection. The infected patient is conta-gious from 24 to 48 hours before developing prodromal syndrome till the appearance of rash. The infection is transmitted by:
· vertical transmission during birth;
· respiratory route through respiratory secretions; and
· percutaneous exposure to blood and transfusion of blood and blood products (pooled RBCs, platelets, intravenous immunoglobulins, etc.).