End-point titer was determined for 64 serum specimens that tested positive for reovirus-specific antibodies by indirect ELISA. commonly infect humans; however, most reovirus infections are thought to be asymptomatic . Previous studies Acolbifene (EM 652, SCH57068) and case reports have linked reovirus infections with minor upper respiratory or gastrointestinal symptoms or with central nervous system disease in children [2C4 ]. An association between reovirus infection and neonatal extrahepatic biliary atresia has been suggested  but remains to be proven. Since few seroepidemiologic studies of reovirus exist, we determined the titers of reovirus-specific antibodies in young children residing in Nashville, Tennessee, from 1989 to 2001 test was used to evaluate differences in seroprevalence among age groups and differences in prevalence of antireovirus and antilysate antibodies. Analysis of variance was used to compare geometric mean titers (GMTs). P .05 was considered to be statistically significant em Results /em Of the 272 serum specimens evaluated in the present study, 64 (23.5%) were found to be positive for reovirus-specific antibodies (figure 1). Thirty-five (25.2%) of 139 from males and 29 (21.8%) of 133 from females were found to be seropositive (P=.512). Rapid loss of maternal antibody was demonstrated by the decrease of seroprevalence from 75.0% in infants 0C3 months of age to 11.1% in those 3C6 months of age (P=.015). Seroprevalence decreased to 0% in children 6C12 months of age and then increased steadily throughout early childhood. In contrast to children 1C2 years of age, who had a seroprevalence of 8.2%, 32.8% of children 4C5 years of age (P=.002) and 50.0% of children 5C6 years of age (P .001) were found to be positive for antireovirus antibodies Open in a separate window Figure 1 Prevalence of reovirus-specific antibodies by age group. Two-hundred seventy-two serum specimens collected from young children were analyzed, by indirect ELISA, for the presence of total IgA, IgG, and IgM specific for type 3 reovirus. The no. of positive specimens and the total no. of specimens for each age group are shown. The error bars represent 95% confidence intervals for each age group. Fishers exact test was used to determine statistical significance of associations To determine the extent to which antimouse antibodies in serum specimens may have caused false-positive results, all specimens were tested against lysates prepared from mock-infected mouse L929 cells. Twenty-eight (10.3%) of the 272 specimens were found to be positive for antimouse antibodies (26 with a titer of 1 1:160 and 2 with a Acolbifene (EM 652, SCH57068) titer of 1 1:640); of these, all but 6 were found to be negative for reovirus-specific antibodies. Of the 244 specimens found to be negative for antimouse antibodies, 186 were found to be negative for reovirus-specific antibodies. There was no significant difference in the prevalence of antimouse antibodies among reovirus-seropositive and -seronegative specimens (P=.82), suggesting that cross-reactivity between murine and reovirus antigens did not confound the results In the 64 serum specimens found to be positive, antibody titers ranged from 1:160 to 1 1:10,240 (figure 2). Forty-three (67.2%) of the 64 serum specimens found to be positive had titers of either 1:160 or 1:640. There were no significant differences in GMTs for all age groups Open in a separate window Figure 2 Titers of reovirus-specific antibodies in seropositive subjects, by age group. End-point titer was determined for 64 serum specimens that tested positive for reovirus-specific antibodies by indirect ELISA. Each diamond represents the log2 reciprocal titer for an individual sample obtained from a Acolbifene (EM 652, SCH57068) unique study participant. The horizontal line for each age group designates the geometric mean titer (GMT) for that group. GMTs are as follows: 1:215 for 0C3 months of age, 1:160 for 3C6 months of age, 1:438 for 1C2 years of age, 1:586 for 2C3 years of age, 1:718 for 3C4 years of age, 1:691 for 4C5 years of age, and 1:527 for 5C6 years of age Seropositivity and GMTs did not vary significantly between specimens from the different collection periods. Twenty-four (22.4%) of the 107 specimens collected during 1989C1991 were found to be positive, as were 21 (21.6%) Rabbit Polyclonal to p14 ARF of the 97 specimens collected during 1992C1994, 14 (30.4%) of the 46 specimens collected during 1995C1997, and 5 (22.7%) of the 22 specimens collected during 1998C2001. GMTs for these collection periods were, respectively, 1:453, 1:508, 1:999, Acolbifene (EM 652, SCH57068) and 1:1114 em Discussion /em Mammalian reoviruses are common infectious agents in humans. Determining the prevalence of reovirus-specific antibodies can help to elucidate proposed but unproven associations between reovirus infection and clinical disease, such as neonatal extrahepatic biliary atresia or meningitis. The.