Parvovirus B19
Par·vo·vi·rus B19
Parvovirus B19 was first isolated in 1975 from a specimen of healthy donor blood. In 1983 it was linked to erythema infectiosum, also called fifth disease, a generally benign febrile exanthem of children. Parvovirus B19 infection occurs worldwide and can attack people of any age. It is most often contracted in childhood; 30-60% of adults have protective IgG antibody to the virus. Infection is asymptomatic in 20-50% of people who acquire it. Transmission is usually by respiratory secretions. The virus replicates in bone marrow. Classical erythema infectiosum typically occurs in children 4-15 years of age. Sporadic outbreaks are common, and the peak incidence is during the winter and spring. After an incubation period of 4-14 days, the child develops prodromal symptoms, usually mild, consisting of headache, fever, chills, joint pains, and malaise. About 1 week later, a bright red "slapped cheek" rash appears on the face, and during the next 3-4 days the rash spreads to the rest of the body (proximal extremities, then trunk and distal extremities, including palms and soles), where it has a reticular or maculopapular appearance. Itching, if any, is slight. The rash is an immune response, heralding the appearance of IgM antibody and the end of the period of communicability. The disease typically runs a benign course, and treatment is purely symptomatic. (Like certain other viruses, parvovirus B19 also occasionally causes a benign exanthem known as papular-purpuric gloves-and-socks syndrome.) Infection in adults follows a different pattern: the "slapped cheek" appearance does not occur and the rash on the trunk and limbs tends to be milder and more subtle, but 15-20% of adult patients, virtually all women, develop significant joint involvement. Deposition of immune complexes in joint membranes leads to sudden onset of symmetric polyarthritis, with or without swelling, affecting particularly the metacarpophalangeal and proximal interphalangeal joints, the wrists, and the knees. Pain and disability can be severe, and symptoms can persist for weeks or months, but eventual spontaneous resolution is the rule. Because parvovirus B19 infects the bone marrow, most patients experience a transient decline in red blood cells (RBC), white blood cells (WBC), and platelets. Generally this is of no consequence, but occasionally it progresses to a transient aplastic crisis, in which RBC production virtually stops and the RBC count falls rapidly. The risk of this complication is much greater in conjunction with sickle cell anemia, autoimmune hemolytic anemias, immunodeficiency, and pregnancy. With the formation of IgG antibody by the immune system, RBC production resumes and the anemia resolves. In patients with congenital or acquired immune deficiency, however, failure to form antibody can lead to prolonged anemia. Infection in a pregnant woman has about a one-in-three chance of being passed to the fetus and inducing a fetal aplastic crisis. This in turn can result in congestive heart failure and fetal hydrops. Spontaneous recovery is typical, but fetal death occurs in as many as 10% of cases. Fetal infection with parvovirus B19 apparently does not cause congenital anomalies. Acute parvovirus B19 infection can be confirmed by a rapid rise and fall of IgM antibody. Diagnosis can also be established by culturing the virus from bone marrow or by ELISA detection of the antigen in serum. The treatment of all forms of parvovirus B19 infection is purely symptomatic and supportive. Hospitalized patients with parvovirus B19 are isolated, and pregnant workers are advised to avoid contact with them. Severe anemia may require blood transfusions. When prolonged anemia results from inability to form IgM antibody, intravenous immune globulin may help.
Par·vo·vi·rus B19
(pahr'vō-vī'rŭs)parvovirus
(par?vo-vi'rus) [ parvo- + virus]parvovirus B19
See: erythrovirus B19Patient discussion about Parvovirus B19
Q. fifth month of pregnancy... Hey guys, as always, just wanted to let you know my wife and I are getting into fifth. so far doing good and we have some news.......... we're gonna have a girl!!! I'm so happy.... now the name is actually the problem... is true that orange is the new pink??