Banca de DEFESA: RONALD ALVES DOS SANTOS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : RONALD ALVES DOS SANTOS
DATE: 17/12/2021
TIME: 14:00
LOCAL: IGM Sala Virtual 5
TITLE:

Evaluation of the Response Pattern of the Rapid Urine Test for the Diagnosis of Schistosomiasis, POC-CCA, in a High Endemicity Population in the State of Bahia.

KEY WORDS:

Schistosoma mansoni; Diagnosis; POC-CCA.

PAGES: 68
BIG AREA: Ciências Biológicas
AREA: Parasitologia
SUMMARY:

ABSTRACT INTRODUCTION: Schistosomiasis is a neglected disease caused by helminths of the genus Schistosoma, and recognized as an important public health problem that especially affects the poorest communities around the world. Schistosomiasis has a wide distribution around the world, however, it is restricted only to the tropical and subtropical zones, where the parasites and their intermediate hosts live, a factor that influences directly into the global distribution of the disease. According to the World Health Organization (WHO), the people most susceptible to contracting schistosomiasis are those who live in poor areas, whose main source of income is fishing or agriculture in rivers and lakes with infected snails. Diagnosis is performed by parasitological examination of feces, using the Kato-Katz method, which represents a limitation of studies and parasitological surveys, considering the current epidemiological scenario in Brazil. Some diagnostic tests are being proposed and developed all over the world, among them, the POC-CCA rapid urine test stands out. OBJECTIVE: To determine the frequency of positivity of the rapid urine test for the diagnosis of schistosomiasis, POC-CCA, in a population of high prevalence in the state of Bahia, before and after treatment for schistosomiasis. METHODOLOGY: This is a cohort carried out in the city of Conde-BA, located about 170 km from Salvador-BA. Individuals of both sexes aged between 4 and 70 years who delivered stool and urine samples were included. Fecal samples were used to make two Kato-Katz slides, and urine samples were used to perform the POC-CCA and urine reagent strip. For post-treatment analyses, all subjects who received treatment for schistosomiasis and submitted stool and urine samples were included. Follow-up was performed at five times: pre-treatment evaluation (D0), treatment (D30), cure control (D30), follow-up 180 (D180) and 360 (D360) days after treatment. RESULTS: The presence of S. mansoni eggs was identified in 189 individuals (55.59%) with a median parasite load of 36 (12–108) eggs per gram of feces (OPG). For the evaluation of POC-CCA among 273 samples on D0, 58.24% (n=159) were positive for the Circulating Cathodic Antigen (CCA), of these, 18.32% (n=50) were considered false-negative; 19.05% (n=52) false positives; 23.44% (n=64) true-negative and 39.19% (n=107) true-positive. We further demonstrate that urine density is a factor that interferes with the performance of the POC-CCA, where higher density urines increase the chance of false-negative results in the POC-CCA CONCLUSION: The POC-CCA, despite presenting a frequency of positive results greater than that brought about by two Kato-Katz slides, presents a considered number of false-negatives, especially among individuals with low parasite load. The POC-CCA showed the same flaws as the Kato-Katz, with regard to sensitivity in samples with low parasite load, in addition, the method showed to be influenced by urinary density. For this reason, the largescale use of the POC-CCA cannot be recommended in its current format. It is possible that the adequacy of the test or the patient's condition, such as the recommendation to hydrate the patient before collecting the material, or using a buffer solution during sample application, may help to improve the performance of this test in highly endemic regions from Brazil.

BANKING MEMBERS:
Externo à Instituição - CARLOS GRAEFF TEIXEIRA - UFES
Interna - 2573399 - DEBORAH BITTENCOURT MOTHE FRAGA
Presidente - 804.709.555-20 - RICARDO RICCIO OLIVEIRA - UFBA