Pathogenesis and Pathology of Parvoviruses
المؤلف:
Stefan Riedel, Jeffery A. Hobden, Steve Miller, Stephen A. Morse, Timothy A. Mietzner, Barbara Detrick, Thomas G. Mitchell, Judy A. Sakanari, Peter Hotez, Rojelio Mejia
المصدر:
Jawetz, Melnick, & Adelberg’s Medical Microbiology
الجزء والصفحة:
28e , p457-460
2025-11-02
51
A typical course of human parvovirus B19 infection in adults is illustrated in Figure1. B19 has been implicated as the causative agent of several diseases (Table 1). Immature cells in the erythroid lineage are principal targets for human B19 parvovirus. Hence, the major sites of virus replication in patients are assumed to be the adult marrow, some blood cells, and the fetal liver. Viral replication causes cell death, interrupting red blood cell production. Bone marrow biopsies from infected patients show erythrocyte maturation arrest, with erythroblast intranuclear inclusions. In immunocompromised patients, persistent B19 infections occur, resulting in chronic anemia. In cases of fetal death, chronic infections may have caused severe anemia in the fetus.
Fig1. Clinical and laboratory findings during the course of human parvovirus B19 infection in adult volunteers. The first phase of illness with flu-like symptoms coincides with viremia (days 6–12); the second phase of illness with rash appears on about day 18. (Reproduced with permission from Anderson LJ, Erdman DD: Human parvovirus B19. In Richman DD, Whitley RJ, Hayden FG [editors]. Clinical Virology, 3rd ed. Washington DC: ASM Press, 2009; ©2009 American Society for Microbiology. No further reproduction or distribution is permitted without the prior written permission of American Society for Microbiology. Data taken from Anderson MJ, Higgins PG, Davis LR, et al: Experimental parvoviral infection in humans. J Infect Dis 1985;152:257–265.)
Fig2. Human Diseases Associated with B19 Parvovirus
Because nondefective parvoviruses require dividing host cells to replicate, known parvovirus diseases reflect that target specificity (Figure 2).
Fig2. Pathogenesis of diseases caused by B19 parvovirus. A: In children and adults. (PRCA, pure red cell aplasia; TAC, transient aplastic crisis.) B: In fetal infections. (Modified with permission from Brown KE, Young NS: Parvovirus B19 infection and hematopoiesis. Blood Rev 1995;9:176. Copyright Elsevier.)
Both virus-specific immunoglobulin M (IgM) and IgG antibodies are made after B19 infections. Persistent parvovirus infections occur in patients with immune deficiencies who fail to make virus-neutralizing antibodies, resulting in anemia. Persistence of low levels of B19 DNA has also been detected in blood, skin, tonsil, liver, and synovial tissues of immunocompetent persons. The rash associated with erythema infectionsum is at least partly immune complex mediated.
B19 can be found in blood and respiratory secretions of infected patients. Transmission is presumably by the respiratory route. There is no evidence of virus excretion in feces or urine. The virus can be transmitted parenterally by blood transfusions or by infected blood products (coagulation factors and immunoglobulin concentrates) and vertically from mother to fetus. Because B19 can be present at extremely high titers and is resistant to harsh treatments that inactivate enveloped viruses, plasma derived clotting factor concentrates can end up contaminated and are screened for the presence of B19 DNA. The prevalence of antibodies to B19 is higher among people with hemophilia than the general population; however, the minimal level of virus in blood products able to cause infections is not known.
The pathogenesis of human bocavirus infection is not yet known, though some studies have associated its presence with respiratory disease. Because it has been found in respiratory specimens, it is presumed to infect the respiratory tract and be transmitted by the respiratory route. It has also been detected in stool and serum samples.
Several pathogenic parvoviruses of animals replicate in intestinal mucosal cells and cause enteritis. Consistent with their highly stable nature, parvoviruses have also been found contaminating laboratory reagents.
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