Continued high caseload of rheumatic fever in western Pennsylvania: Possible rheumatogenic emm types of streptococcus pyogenes.

OBJECTIVE: To evaluate the occurrence of cases of acute rheumatic fever (ARF) in western Pennsylvania although there has been a marked reduction of cases of ARF in the United States overall.

STUDY DESIGN: From 1994 to 2003, the cases of ARF evaluated at Children's Hospital of Pittsburgh were reviewed. In addition, throat cultures were performed on a subset of these children and their family members beginning in 1995. Molecular typing was performed on isolates of the group A streptococcus (GAS) recovered, using field inversion gel electrophoresis (FIGE) and emm typing.

RESULTS: There were 121 new cases of ARF from 1994 to 2003. Of these, 57% were male. The median age was 10 years. The majority of children (57%) had carditis with or without another manifestation of ARF. The results of throat cultures were available for 231 persons; 36% (30/84) of the children with ARF and 14% (20/147) of family members were positive for GAS. Eight emm types were observed (emm 1, 2, 6, 12, 18, 28, 75, and 89). Data suggest that emm type 12 may be a rheumatogenic strain.

CONCLUSION: ARF remains a problem in western Pennsylvania. Identification of emm types associated with cases should enlighten vaccine development.