Performance of POC-CCA® in diagnosis of schistosomiasis mansoni in individuals with low parasite burden

Abstract: INTRODUCTION: Schistosomiasis, caused by Schistosoma mansoni, is a public health concern in Brazil. However, the most popular diagnostic method, the Kato-Katz technique, exhibits low sensitivity in low-endemicity areas. We aimed to compare the performance of an immunological assay, the point-of-care circulating cathodic antigen (POC-CCA®) test, with that of two parasitological techniques in a low-endemicity population. METHODS: Our study included 141 individuals living in Estreito de Miralta, Minas Gerais, Brazil. Fecal samples were obtained from all participants and analyzed for schistosomiasis using two parasitological techniques: the Kato-Katz technique and the saline gradient technique. Additionally, POC-CCA® strips were utilized for testing urine samples. The results obtained by the different techniques were compared. RESULTS: Analysis of two or 24 slides using the Kato-Katz technique resulted in a positivity rate of 10.6% (15/141) or 19.1% (27/141), respectively. The saline gradient technique yielded a positivity rate of 17.0% (24/141). The prevalence according to both parasitological techniques was 24.1% (34/141). The POC-CCA® test yielded a positivity rate of 22.7% (32/141); however, the positivity rate was merely 2.1% if trace results were considered negative. The agreements observed between POC-CCA® and the parasitological techniques were good (Kappa indexes > 0.64). The POC-CCA® test was more sensitive than the two-slide Kato-Katz technique (p < 0.05) in detecting cases of S. mansoni infection when trace results were considered positive. CONCLUSIONS: These findings reinforce the importance of using multiple diagnostic techniques in low-endemicity areas for effective control of disease.

Desenvolvimento da leishmania mexicana amazonensis em diferentes cepas de camundongos isogênicos / Development of Leishmania mexicana amazonensis in different strains of isogenic mice

Acompanhou-se o desenvolvimento da Leishmania mexicana amazonensis em sete cepas de camundongos isogênicos (BALB/c, C3H, DBA/2, CBA, ABY, ASW e C57BL/10). Todas foram susceptíveis ao parasito, com 100 por cento de animais infectados. Maiores lesöes foram observadas no CBA e BALB/c enquanto no ABY ocorreu menor desenvolvimento, näo sendo observado auto-cura. Sugere-se o uso das cepas CBA e BALB/c para trabalhos com leishmaniose difusa e as demais para estudos com vacinas.