Cost-benefit of a streptococcal surveillance program among Navajo Indians.

A school-based streptococcal surveillance program has been in effect among Navajo Indians for more than 4 years. Throat cultures of symptomatic children are obtained when indicated, and routine throat cultures are performed monthly. Children whose cultures are positive for group A beta-hemolytic streptococci are treated. During 4 academic years, between 48 percent and 56 percent of elementary school children attended the schools that had 4 or more monthly surveys in each year, but only 24 percent (7 of 29) of the acute rheumatic fever (ARF) cases occurred in children at those schools. Six of seven children attending covered schools were not cultured before their ARF episodes. Five cases occurred in children attending previously covered schools, during years in which participation lapse. Three or four ARF cases per year appeared to have been prevented, but the program's costs were five times the estimated costs of the prevented cases, even excluding risks of allergic reactions to penicillin. There is little evidence that most asymptomatic carriers are at risk to develop ARF. The authors recommend that streptococcal surveillance efforts be confined largely to culturing throat swabs of children with pharyngitis.