Morbidity of schistosomiasis mansoni in a low endemic setting in Ouro Preto, Minas Gerais, Brazil

Abstract INTRODUCTION: Despite the advances of disease control programs, severe forms of schistosomiasis are prevalent. The prevalence of the disease in areas frequented by tourists urges for permanent prevention and control. The aim of this study was to describe the morbidity of schistosomiasis in the district of Antônio Pereira, Ouro Preto, Minas Gerais, Brazil. METHODS: The proportion of positives was defined by Kato-Katz coproscopy and urinary POC-CCA rapid test. Hepatosplenic form was diagnosed using abdominal ultrasound. RESULTS: Out of 180 participants,97 were examined by Kato-Katz, with 4 (4.1%) being positive. Thirty-four (22.1%) out of 154 were positive by POC-CCA. Five (2.8%) of 177 examined by ultrasound had hepatosplenic form. One of them had undergone splenectomy. One (0.6%)participant had myeloradiculopathy. CONCLUSIONS: Severe forms of schistosomiasis are still prevalent in low endemic areas and should be thoroughly investigated.

Sensitivity and specificity of the circulating cathodic antigen rapid urine test in the diagnosis of Schistosomiasis mansoni infection and evaluation of morbidity in a low- endemic area in Brazil

Abstract INTRODUCTION: The Kato-Katz technique is the standard diagnostic test for Schistosoma mansoni infection in rural areas. However, the utility of this method is severely limited by the day-to-day variability in host egg excretion in the stool. In high-transmission areas, the point-of-care circulating cathodic antigen (POC-CCA) urine assay has proven to be a reliable test. However, investigations of the reliability of the POC-CCA assay in low-transmission regions are under way. This study aimed to evaluate the sensitivity and specificity of the POC-CCA assay and the morbidity of schistosomiasis in a low-endemic area in Brazil. METHODS: Pains City is a low-transmission zone for schistosomiasis. A total of 300 subjects aged 7-76 years were randomly selected for the POC-CCA cassette test. For S. mansoni diagnosis, three stool samples on six slides were compared with one urine sample for each subject. The sensitivity and specificity in the absence of a gold standard were calculated using latent class analysis. Clinical examinations and abdominal ultrasounds were performed in 181 volunteers to evaluate morbidity associated with schistosomiasis. RESULTS: The sensitivity and specificity of the Kato-Katz technique were 25.6% and 94.6%, respectively. By contrast, the sensitivity and specificity of the POC-CCA assay were 68.1% and 72.8%, respectively. Hepatosplenic schistosomiasis was diagnosed in two patients (1.1%). CONCLUSIONS: Overall, the POC-CCA urine assay proved to be a useful test for diagnosing S. mansoni in a low-endemic area in Brazil. Severe clinical forms of schistosomiasis can be present even in such low-endemic areas.

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.

Urinary antingen detection for diagnosis of hydatid disease

Hydatid antigen was demonstrated for the first time in urine of patients with hydatidosis by coagglutination test [Co-A]. Urinary antigen was detected in all Co-A positive serum corresponding samples of surgically confirmed hydatid disease. The sensitivity and specificity were 100% in urine compared with the corresponding serum samples. These results clarified that the use of Co-A test for the detection of hydatid antigen in urine is an easy, simple, rapid, noninvasive and efficient method for the diagnosis of hydatidosis

Fast-dot ELISA using urine, a rapid and dependable field assay for diagnosis of schistosomiasis

The fast dot-enzyme linked immunosorbent assay [FD-ELISA] was used as a field applicable tool for rapid diagnosis of schistosomiasis. 700 fecal specimens were parasitologically examined for detection of S. mansoni eggs and other parasitic infection. Egg count was done for 100 infected patients. Rectal biopsies [394] were taken from individuals with no S. mansoni egg in their stool where it was used as golden standard for diagnosis of schistosomiasis. Cross- reactivity with other parasites was studied. Serum samples were tested by ELISA technique for detection of human IgG anti-schistosomal antibodies. 700 urine samples [433 S. mansoni infected patients and 267 healthy individuals] were tested by FD-ELISA for detection of a schistosomal antigen excreted in urine using BRLF4 mouse monoclonal antibody. FD- ELISA results were compared with ELISA detecting antischistosomal IgG and stool analysis where it showed highest efficiency [91%] compared with 81% and 60% for ELISA and stool analysis, respectively. The sensitivity of FD-ELISA was high ranging from 90 to 94% in the 4 different clinical stages of schistosomiasis [simple intestinal, hepatosplenomegaly, shrunken liver and splenomegaly, and shrunken liver-splenomegaly and ascites]. FD-ELISA was highly sensitive, detecting infection cases with 20 eggs/g feces and its specificity was 89%. The antigen was characterized as a protein with a molecular weight of 74 KDa using Western Blot technique