Monday, October 3, 2011

Parvovirus B19 (PB19)

Parvovirus B19 (PB19) virion is DNA virus. It has a simple structure composed of only 2 proteins and a linear, single stranded DNA molecule. The non enveloped viral particles are 22 to 24 nm in diameter with icosahedral symmetry, and both empty and full capsids are visible by negative staining and electron microscopy. PB19 is an autonomous virus; its replication is dependant on cellular factors expressed transiently in the cell during the late S or early G2 phases of mitosis. The pathogenesis of PB19 is associated with erythroid tropism. The life cycle of PB19 like those of other non-enveloped DNA viruses. PB19 DNA has been found in the respiratory secretions at the time of viremia; transmission of infection via the respiratory route seems to be the most common route of spread of infection. Vertical transmission (from mother to fetus) occurs in one-third of cases involving serologically confirmed primary maternal infections.
Furthermore, PB19 infection can be transmitted via blood derived products administrated parentally as the virus presents in high titers in the serum and is resistant to conventional heat treatments. Viremia is accompanied by constitutional symptoms of fever and malaise, and by erythroid progenitor cell depletion in the BM

Parvovirus B19 and Hematological Disorders in Children

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