New normal ranges of antistreptolysin O and antideoxyribonuclease B titres for Australian children.

OBJECTIVE: To determine age-specific upper limit of normal (ULN) values of the ASO and ADB titres in children aged 4-14 years in urban Melbourne. Serology is often used to diagnose a preceding Streptococcus pyogenes infection, particularly in potential cases of rheumatic fever and post-streptococcal glomerulonephritis. The most commonly used antigens are antistreptolysin O (ASO) and antideoxyribonuclease B (ADB). Reference ranges used in Australia for these serological markers are usually based on data in adults from other countries. There are no age-specific reference values for Australian children. METHODS: Sixty-six sera from children with no history of recent streptococcal infection were obtained in May-June 2002. The children were divided into three age groups for analysis: 4-5 (n = 20), 6-9 (n = 19) and 10-14 (n = 25) years. The geometric mean titre and ULN (defined as the 80th percentile) for the ASO and ADB titres for each age group were determined in both international and log units. RESULTS: The ULN for ASO titres in each age group was 120 (2.08 log units), 480 (2.68) and 320 (2.51). The ULN for ADB titres in each age group was 100 (2.00 log units), 400 (2.60) and 380 (2.58). CONCLUSION: The ASO and ADB ULN values in school-aged children are higher than the current reference ranges suggest.

Hepatitis C--role of perinatal transmission.

To evaluate the role of perinatal transmission in the spread of hepatitis C virus (HCV), we screened a cohort of pregnant intravenous drug using (IVDU) women for HCV antibody detection; where seropositive HCV RNA detection by polymerase chain reaction (PCR) was found we followed the infants longitudinally for HCV antibody and HCV RNA. Serum prevalence for HCV for this population was 80% with HCV RNA detected in 50%. Recruitment and follow-up over a 3-year period of a cohort of 83 seropositive women, their 91 newborns and 16 siblings of newborns, showed that there had been a 3% perinatal transmission rate with 1 sibling also infected. These positive cases were defined as transient in 1 case (HCV RNA positive by PCR at 1 month, but seronegative and HCV RNA negative at 10 months of age), 2 unevaluable (HCV RNA positive at 2 months of age, but patients lost to follow-up), and 1 chronic infection in a child at 34 months (positive HCV RNA and seropositive 34-month sibling). Maternal HCV RNA levels for those with infected infants was a mean 40-fold greater than those whose babies were uninfected, although this did not reach statistical significance. Of the remaining infants, the majority (93%) had lost passively acquired maternal antibodies by 9 months of age and all by 12 months. Of 18 women who were HCV seropositive and breast feeding (66% of whom were HCV RNA positive in their sera), none had detectable HCV RNA in breast milk. Hence we conclude that transmission of HCV from mother to infant appears to be of low frequency and positivity appears to correlate with maternal circulating viral load.

An outbreak of puerperal fever caused by group C streptococci.

Between 19 February and 18 April 1987, 33 confirmed cases of puerperal fever caused by Streptococcus equisimilis serotype T204 occurred at three hospitals in and around Chelmsford. Most of the cases (70%) occurred on one ward, in which toilet seats and a shower are believed to have aided transmission, although insufficient data were obtained to exclude a role for person-to-person spread. Possession of M-protein antigen was demonstrated in the outbreak strain.