From ACP Medicine Online Posted 06/07/2006 Martin S. Hirsch, M.D.
Although only recently recognized as a human pathogen, parvovirus B19 is now appreciated as a cause of several syndromes in both children and adults.
Parvovirus B19, a small (20 to 26 nm), single-stranded DNA virus, causes erythema infectiosum (fifth disease) in normal persons, aplastic crises in persons with underlying hemolytic disorders, chronic anemia in immunocompromised hosts, and fetal loss in pregnant women.36-40
Epidemiology
Parvovirus B19 infection occurs most commonly in school-age children in outbreaks during late winter and spring.
Only 2% to 15% of pre-school-age children have antibodies, but seroprevalence increases to 35% to 60% by 11 to 19 years of age and to greater than 75% in persons older than 50 years.41
Respiratory transmission is likely and is facilitated by close contact.
Hospital outbreaks have also been described and are often traced to patients with aplastic crises who carry large amounts of virus in blood and respiratory secretions.42,43
Maternal infection can lead to fetal anemia, hydrops fetalis, heart failure, and death, resulting in spontaneous abortion, most commonly 4 to 6 weeks after infection.
When women are infected during the first 20 weeks of pregnancy, the risk of parvovirus-related fetal death is approximately 9% to 10%.44,45 Routine antenatal screening is not recommended.38,46
Pathogenesis
Replication of parvovirus B19 has been demonstrated in human erythroid progenitor cells, and the receptor appears to be the P blood group antigen globoside, a neutral glycosphingolipid, which occurs in erythrocytes, erythroblasts, megakaryocytes, endothelial cells, placenta, and fetal liver and heart cells.47
Expression of this glycosphingolipid in tissues helps to determine parvovirus B19 tropism.48
Persons who lack erythrocyte P antigen (p phenotype) are naturally resistant to infection,37,49 and the distribution of parvovirus in infected individuals is linked to the presence of the P antigen.
Although little is known about the pathogenesis of parvovirus, antiviral antibodies--particularly those directed against the capsid protein VP1--appear to be responsible for viral clearance.
The presence of certain HLA class I and class II alleles may be associated with more symptomatic parvovirus infections.50
Diagnosis
Clinical Features
The rash caused by parvovirus B19, erythema infectiosum, usually appears without prodromal symptoms after an incubation period of 4 to 14 days.
The exanthem progresses through three stages. Initially, a fiery-red rash develops on both cheeks (giving them the appearance of having been slapped), accompanied by relative pallor around the mouth. >From 1 to 4 days later, an erythematous maculopapular eruption appears on the proximal extremities and spreads to the trunk in a lacelike, reticular pattern. The third stage, during which the eruption waxes and wanes, may persist for several weeks and may be precipitated by skin trauma, exposure to sunlight, or extremes of temperature.
Arthralgia and arthritis are seen in up to 80% of infected adults; arthralgia is particularly common in women, may occur without rash, and may linger for weeks.
Joint involvement is often symmetrical in the hands, wrists, knees, and ankles. Hemolytic anemias and encephalopathies are rare complications.
Laboratory Tests
Parvovirus-specific IgM antibodies usually appear within 3 days after symptoms develop; these antibodies persist for several weeks and then rapidly decline.
IgG antibodies, however, persist for years. Viral DNA can also be detected in blood, tissues, and secretions, although culture techniques for virus isolation are unsatisfactory.
Complications
Transient aplastic crises associated with parvovirus B19 occur in patients who have sickle cell anemia, hereditary spherocytosis, thalassemia, and various other hemolytic anemias.51
These aplastic crises are abrupt in onset and associated with giant pronormoblasts in the bone marrow.
They generally last 1 to 2 weeks and go into remission spontaneously. In immunocompromised hosts (e.g., patients with HIV infection), acute infection may lead to viral persistence and chronic bone marrow suppression.40
A significant proportion of patients with AIDS who develop severe anemia while receiving zidovudine (AZT) have persistent parvovirus infection.51
Pneumonia, hepatitis, and myocarditis have also been associated with parvovirus infections in immunocompromised as well as immunocompetent adults and children.52-57
Although parvovirus B19 has been implicated in a variety of rheumatic diseases, there is no definitive evidence for a causal role.
Treatment
Pooled human immune globulin contains anti-parvovirus B19 antibodies and has been used to treat persistent infections as well as acute exposures.40
Prevention of nosocomial infections is of great concern: pregnant health care workers should not care for patients with aplastic crises.
Droplet isolation is recommended for such patients, including the use of gowns, gloves, and masks during close contact.
Because certain blood products (e.g., clotting factors) contain parvovirus B19 DNA, screening of products, donors, and recipients has been suggested.58
Click here to subscribe or purchase the full chapter. Hirsch, Martin S, 7 Infectious Disease, XXIX Measles, Mumps, Rubella, Parvovirus, and Poxvirus, ACP Medicine Online, Dale DC; Federman DD, Eds. WebMD Inc., New York, 2000. http://www.acpmedicine.com/ Disclaimer
Figures, tables, references and sidebars are available in the subscription edition of ACP Medicine .
Martin S. Hirsch, M.D., Professor of Medicine, Harvard Medical School, Physician, Massachusetts General Hospital
ACP Medicine Online. 2002; �2002 WebMD Inc.
[ 08. January 2008, 12:17 PM: Message edited by: AliG ]
-------------------- Note: I'm NOT a medical professional. The information I share is from my own personal research and experience. Please do not construe anything I share as medical advice, which should only be obtained from a licensed medical practitioner. Posts: 4881 | From Middlesex County, NJ | Registered: Jul 2006
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JRWagner
Frequent Contributor (1K+ posts)
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posted
Thanks Ali...I guess Parvo is not just for Dogs anymore.
Perhaps I should also be checked for WORMS!!!??
Na...
Peace, Love and Wellness, JRW
Posts: 1414 | From Ny, Ny | Registered: Oct 2002
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AliG
Frequent Contributor (1K+ posts)
Member # 9734
The most common manifestation of human parvovirus B19 infections is erythema infectiosm ("Fifth Disease"). This is characterized by mild symptoms, fever (in some patients) and a red rash on the face ("slapped cheek"). Arthralgia and arthritis have been seen occasionally in children and commonly in adults (particularly women).
However, human parvovirus B19 can also result in chronic infections in immunocompromised patients, and produce aplastic crisis in people with sickle-cell disease. Infection during pregnancy can cause fetal hydrops and fetal death (less than 10%).
Transmission is believed to be through respiratory secretions between humans, the only known reservoir for parvovirus B19. There are no known therapies; in most cases, supportive care is all that is required.
Human Parvovirus B19 A negatively stained preparation of parvovirus as seen by transmission electron microscopy. The individual virions have a diameter of only 22nm. (nm=one-millionth of a millimeter)
* Clinical Virology Program - Virus Reference and Surveillance Laboratory (VRSL)- Parvovirus B19 * Learn more about Fifth Disease.
-------------------- Note: I'm NOT a medical professional. The information I share is from my own personal research and experience. Please do not construe anything I share as medical advice, which should only be obtained from a licensed medical practitioner. Posts: 4881 | From Middlesex County, NJ | Registered: Jul 2006
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