Stool examination and rectal biopsy in the diagnosis and evaluation of therapy of schistosomiasis mansoni

Abstract

From each of a group of 217 adult males selected through enzyme-immunoassay or skin-test (Group A), six stool samples were examined by both the Lutz/Hoffman, Pons & Janer (Lutz/HPJ) and Kato/Katz methods. In addition, one oogram of the rectal mucosa was performed. By these methods, schistosomiasis was detected in 44.7%, 47.5% and 40.1% of the individuals respectively. To evaluate the methods in the assessment of cure, the last 40 patients from group A, treated with a single oral dose of oxamniquine at 15 mg/kg were followed up for six months (Group B). The criteria for parasitological cure included three stool examinations by Kato/Katz and Lutz/HPJ methods, one, three and six months post-treatment and a rectal biopsy between the fourth and sixth months post-treatment. The examinations were negative in 87.5%, 90% and 95% of the patients, respectively. The efficacy of oxamniquine was 82.5% when the three methods were considered together and there was no statistically significant difference between the sensitivity of the individual methods.

Prevalência da infecção pelo Schistosoma mansoni em dois municípios do Estado de Alagoas

“…Tal fato demonstra uma baixa sensibilidade dos métodos diagnósticos utilizados. Ocorrência que pode ser revertida pelo aumento do número de amostras examinadas, uma vez que os métodos coproscópicos são equivalentes 24 .…”

Diagnosing Schistosomiasis

“…This procedure is mainly indicated when the population group studied presents a low prevalence and a low intensity of infection and in the control of cure, situations in which the expected number of eggs in the feces is small. The sensitivity of the examination of only one fecal sample compared to the examination of four samples was of 84.9% and 100% when the number of eggs per gram of feces was greater than 50, 100 and 500, respectively, in an endemic area of low prevalence and intensity of infection (Rabello et al 1992).…”

“…Regarding the available techniques for the parasitological feces examination, in the most recent publications it remains the consonance that the Kato-Katz method (Katz et al 1972) offers the best conditions of effectiveness associated to the cost and operational conditions (Mott & Cline 1980, Sleigh et al 1982, Rabello et al 1992, WHO 1993.…”

“…These are patients with a low shedding of eggs in their feces, with less chance of developing serious forms and which may be reevaluated in the following stage in a well established longitudinal program. The resource which was saved with the unnecessary treatment, makes possible the repetition of the feces examination, highly increasing its sensitivity (Rabello et al 1992).…”

Comparative randomised trial of high and conventional doses of praziquantel in the treatment of schistosomiasis mansoni

“…For example, some authors prefer rectal biopsy for cure control (da Cunha et al 1987), but this method is difficult to perform in field condition. Therefore, most investigators defend the use of repeated stool examinations (Rabello et al 1992). Increasing the number of stool examinations will increase the probability of finding positive samples and consequently decrease the putative efficacy of the drug.…”