Comparison of a polymerase chain reaction and the Kato-Katz technique for diagnosing infection with Schistosoma mansoni.
Fecal samples from 194 individuals living in an area of Brazil endemic for Schistosoma mansoni were analyzed by a polymerase chain reaction (PCR) and the Kato-Katz parasitologic examination. Statistical analysis of the results showed a kappa index of 0.8 between the two methods. The prevalence of infection was 30.9% in three fecal samples examined by the Kato-Katz method, but 38.1% in one fecal sample examined by the PCR technique. Repeated survey of discordant results showed that five (41.6%) of 12 parasitologically negative cases for which PCR gave positive results were misdiagnosed by Kato-Katz examinations. The PCR technique showed a sensitivity of 96.7% and a specificity of 88% when the parasitologic examination was used as the reference test. The efficacy of cure with praziquantel was 87.8% in three parasitologic stool examinations and 75.6% in one PCR survey. These results demonstrate that the PCR assay might be a valuable alternative for diagnosing Schistosoma infections.
Pontes
Luis A
LA
Laboratory of Clinical Research, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil. luis@cpqrr.fiocruz.br
Oliveira
Maria C
MC
Katz
Naftale
N
Dias-Neto
Emmanuel
E
Rabello
Ana
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D019353:Endemic Diseases; D005243:Feces / Q000469:parasitology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010270:Parasite Egg Count / Q000379:methods*; D016133:Polymerase Chain Reaction / Q000379:methods*; D011237:Predictive Value of Tests; D015995:Prevalence; D012550:Schistosoma mansoni / Q000235:genetics / Q000302:isolation & purification*; D012555:Schistosomiasis mansoni / Q000175:diagnosis* / Q000453:epidemiology / Q000469:parasitology; D012680:Sensitivity and Specificity