PARVOVIRUS B19 INFECTION – THE VIRUS

• Nonenveloped DNA virus.
• B19 is the only strain that is pathogenic in humans. It does not infect other animals, as mammalian parvoviruses are very species specific.
• Replication has only been demonstrated in human progenitor cells,
• The virus binds to an antigen of the P-system blood group known as P antigen or globoside.
• P antigen is present on erythrocytes, erythroblasts, megakaryocytes, endothelial cells, placental cells, fetal liver and heart cells.
• Rarely an individual may lack the P antigen and be resistant to infection by Parvovirus B 19 (1).
• The virus causes lysis of red blood cell precursors in the fetus resulting in aplasia and severe anemia (which may precipitate fetal hydrops and congestive cardiac failure (2).
• The fetus is particularly vulnerable as it has a rapidly expanding red-cell volume and a shorter red-cell life span (2).
• Labratory tests for viral infection.

REFERENCES

1. Brown KE, Anderson s, Young NS. Erythrocyte P antigen: Cellular receptor for B19 parvovirus. Science 1993;262:114.
2. Torok TJ, Wang Q-Y, Gary GW et.al. Prenatal diagnosis of intrauterine infection with parvovirus B19 by the polymerase chain reaction technique. Clin Infect Dis 1992;14:149-155.