Risk of infection following exposures to human parvovirus B19

In response to concern about the effect of human parvovirus B19 infection of the fetus, we have developed estimates of the risk of adults becoming infected following B19 exposures at home, in schools or day-care centers, and in hospitals. These estimates can then be used with other data to estimate the risk to the fetus of a B19 exposure during pregnancy. The risk to the fetus equals the rate of maternal susceptibility to infection times the rate of maternal infection following the specific type of exposure times the rate of fetal death following maternal infection. Data from studies of outbreaks of B19 associated erythema infectiosum and aplastic crisis suggest that the risk of infection among susceptible adults following household exposure to a B19 infected person is approximately 50% and following school exposures during outbreaks of erythema infectiosum is 20% to 30%. All susceptible school staff members, not just teachers, appear to be at risk for infection during outbreaks. Additional study is needed to determine the risk of infection following exposure to B19 infected patients in the hospital. Based on these and other data we can estimate that pregnant women whose serologic status is unknown have less than 2.5% chance of suffering fetal loss after household exposure and less than 1.5% chance after school exposure.

Occupational risk of human parvovirus B19 infection for school and day-care personnel during an outbreak of erythema infectiosum

Human parvovirus B19, the cause of erythema infectiosum, has recently been associated with adverse fetal outcomes. During a large outbreak of erythema infectiosum in Connecticut, a survey was conducted on 571 (90%) of 634 school and day-care personnel to determine the risk of acquiring B19 infection. Serologic evidence of B19 infection was determined by using an enzyme-linked immunosorbent assay. Of the school and day-care personnel, 58% had evidence of previous B19 infection. The minimal rate of B19 infection in susceptible personnel during the outbreak was 19%. The risk was increased for teachers and day-care providers who had contact with younger children and with greater numbers of ill children. These results suggest that B19 infection is an occupational risk for school and day-care personnel.

Comparison of monoclonal time-resolved fluoroimmunoassay with monoclonal capture-biotinylated detector enzyme immunoassay for adenovirus antigen detection

A sensitive time-resolved fluoroimmunoassay (TR-FIA), adapted from TR-FIA procedures already described, was developed with monoclonal antibodies and compared with several enzyme immunoassays (EIAs) for detecting adenovirus antigens in clinical specimens. The most sensitive EIA was an all-monoclonal assay with biotin-labeled detector antibody and streptavidin-peroxidase conjugate. All tests were evaluated with nasopharyngeal aspirate specimens from respiratory illness, with tissue homogenates from patients with systemic infection, and with stool specimens from gastrointestinal illnesses. For respiratory and tissue specimens, the TR-FIA detected adenovirus in 85% of the specimens positive by culture, which was a sensitivity similar to those of the all-monoclonal biotin-avidin EIA (79%) and the polyclonal-capture biotin-avidin EIA (88%). For stool specimens, the TR-FIA detected adenovirus in 100% of the specimens positive by culture, which was a decidedly higher sensitivity than either EIA format (78 and 75%, respectively). The TR-FIA was shown to be an efficient, flexible, and specific test for large numbers of clinical specimens.