A total of 1397 sera collected from 1095 cases of exanthematic disease notified as measles in ES and RJ states during July 1992 to December 1994 were investigated. These sera were first tested for measles and rubella specific IgM. When they proved negative, they were tested for B19 specific IgM by an enzyme immunoassay. B19 infection was confirmed in 27 (2.5%) of these cases. Sera from 194 negative cases for measles and rubella IgM received from other Brazilian states were also investigated and B19 infection was confirmed for 11 of them. Sera from these 38 IgM positive cases for B19, were tested for anti-B19 IgG by an enzyme immunoassay and for B19 DNA by dot blot hybridization. Anti-B19 IgG antibodies were detected in most of the acute sera. B19 DNA was detected in the acute serum of one patient that had been splenectomized before. As the exanthem caused by human parvovirus infection may be clinically diagnosed as rubella, it could be important to diagnose B19 infection in Brazil since it is becoming prevalent as the cause of rash in countries where rubella is controlled by vaccination.
Um total de 1397 soros colhidos de 1095 casos de exantema notificados como sarampo, nos estados do ES e RJ, no período de julho de 1992 a dezembro de 1994, foram investigados. Estes soros foram inicialmente testados para sarampo e rubéola por detecção de IgM específica. Os casos negativos foram então testados para a presença de IgM específca anti-B19 por um ensaio imunoenzimático. A infecção pelo B19 foi confirmada em 27 (2,5%) destes casos. Soros de 194 casos negativos para sarampo e rubéola provenientes de outros estados brasileiros foram também investigados, e a infecção pelo B19 pode ser confirmada em 11 destes casos. Os soros dos 38 casos IgM positivos para B19 foram testados para a presença de IgG específica anti-B19 por um ensaio imunoenzimático, e para a presença do ADN viral por hibridização em "dots" (dot blot). IgG específica anti-B19 pode ser detectada na maioria dos soros de fase aguda, e o ADN viral foi detectado no soro de fase aguda de um paciente esplenectomizado. Como o exantema causado pela infecção pelo parvovírus humano pode ser clinicamente diagnosticado como rubéola, seria importante realizar o diagnóstico desta virose no Brasil, já que um aumento no número de casos de exantema por B19 tem sido relatado nos países onde a rubéola é controlada por vacinação

Serology for parvovirus B19 has been hampered by limited availability of antigen which has often had to be isolated from viraemic blood donations. We have determined the sequence of the genome of one such isolate (Stu). It is 99% similar to the sequences of two other isolates (Wi and Au) except at the far 5'-end, where it is more similar to the terminus of another isolate (Ala/Alb). Recombinant nonstructural protein, NS, was constructed. Antibodies to NS, as well as to the capsid proteins, VP1/2, were detected in patients with B19 infection.

from 1974, 1980, 1982, 1987 and 1988, four of which occurred during the second half of the year, confirming the seasonality of the disease.

Specific anti-B19 IgM was demonstrated in sera from three children showing transient aplastic crisis. A two years-old boy living in Rio de Janeiro suffering from sickle-cell anaemia showed the crisis during August, 1990. Two siblings living in Santa Maria, RS, developed aplastic crisis during May, 1991, when they were also diagnosed for hereditary spherocytosis. For a third child from this same family, who first developed aplastic crisis no IgM anti-B19 was detected in her sera.

Human parvovirus B19 recently was shown to agglutinate baboon and human erythrocytes. We have now demonstrated that both recombinant and native B19 antigens agglutinate rhesus, cynomolgus, and Saimiri monkey erythrocytes. Using cynomolgus erythrocytes and the recombinant antigen, we developed an immunoglobulin M (IgM) antibody capture hemadherence test (MACHAT) for the detection of specific B19 IgM antibodies in human sera. The results obtained with MACHAT were compared with those obtained with an IgM capture enzyme immunoassay (MACEIA) employing the native antigen routinely used in our laboratory. For 229 patient serum samples, we found 96% agreement between the results of the two assays. There was some evidence that MACHAT was slightly more sensitive than MACELR Our results add to the range of erythrocytes that can be agglutinated by B19 virus and show that native as well as recombinant antigens may be used in MACHAT. Human parvovirus B19, first identified by Cossart et al. (8) while screening blood donations for hepatitis B virus, is now known to cause a spectrum of disease in humans. It commonly infects children, causing erythema infectiosum (2). When adults, particularly females, are infected, they may develop acute arthritis (15). The virus also induces a transient aplastic crisis in patients with underlying hemolytic anemia (14). Prolonged anemia may develop in immunocompromised patients with B19 virus infections (12). In pregnant women, B19 virus can cross the placenta and cause spontaneous abortion or hydrops fetalis and fetal death (6). Many B19 virus infections are, however, asymptomatic (13). No adequate in vitro culture system exists for B19 virus. Laboratory diagnosis has been largely based on immunoglobulin M (IgM) serological analysis with antigen prepared directly from the plasma of viremic blood donors; therefore, it has until recently been restricted to only a few countries and to institutions that have supplies of native antigen. In addition, to establish a capture enzyme immunoassay for B19 IgM (MACEIA), monoclonal antibodies (MAbs) are needed but are difficult to obtain. Using a native B19 antigen (Brlll) that we found during blood donor screening in 1988 (9) and a MAb supplied by L. J. Anderson (Centers for Disease Control and Prevention, Atlanta, Ga.), we were able to set up a MACEIA to perform B19 virus diagnosis at Fundacao Oswaldo Cruz, Rio de Janeiro, Brazil (10). This test, however, was insensitive in comparison with the IgM capture radioimmunoassay (MACRIA) performed at the Virus Reference Division, Central Public Health Laboratory, London, United Kingdom (results not shown). Although B19 is a member of the autonomous parvovirus

Serum and saliva samples were simultaneously collected from patients with B19 infection. Specimens were collected in a period of 1 to 18 days after the onset of symptoms. Saliva samples were collected with a commercial device, OraSure. The quality of these samples was evaluated by determining the concentration of total immunoglobulin G (IgG) by an enzyme immunoassay. The concentration of IgG in these samples ranged from 4.8 to >250 mg/liter. B19 infection was confirmed for 20 patients by testing sera in a 1:100 dilution by an IgM capture enzyme immunoassay (MACEIA) and an IgM capture hemadherence test (MACHAT). Saliva samples from these IgM-positive patients were tested neat by MACEIA and MACHAT. IgM could be detected in 11 of 20 (55%) samples by MACEIA and in 15 of 18 (83%) samples by MACHAT. Serum and saliva samples from a further 17 patients with rash were also tested. All of these specimens were unreactive by both assays. These results show that saliva may be a convenient alternative to serum for the diagnosis of recent B19 infection.