Desempenho dos métodos de Kato-Katz e Helmintex para o diagnóstico da esquistossomose mansoni em área endêmica no Estado de Sergipe

Abstract

Schistosomiasis is a parasitic infection caused by the helminth Schistosoma mansoni and represents a serious public health problem in tropical regions, affecting more than 250 million people worldwide. In Sergipe, the disease is endemic and affects more than 65% of the state's municipalities. The Schistosomiasis Control Program (SCP) uses the Kato-Katz (KK) method for population screening, as recommended by the World Health Organization, but there is growing evidence for the sensitivity limitations associated with KK, especially in areas with low parasite loads. Helmintex (HTX) is a sensitive egg detection method based on the magnetic properties of S. mansoni eggs and their isolation in a magnetic field. The aim of this study is to evaluate both KK and HTX in an endemic area for schistosomiasis in Sergipe, Areia Branca, located in the municipality of Pacatuba. Individuals from six years older who signed the term of consent and/or free and informed assent and who provided fecal samples in sufficient quantity to carry out the tests participated in the project. At the end, the results were delivered to the population and all positive individuals were treated. A total of 234 individual fecal samples were delivered and two KK thick smears were prepared and evaluated for each sample. A total of 30g of each fecal sample was processed by the HTX method. Eggs were detected in 80 (34.18%) of the participants. Twenty-three (9.83%) samples were positive by the KK method and 77 (32.91%) by the HTX method. A total of 95.7% (22/23) of the positive samples in the KK method had mild infections and only one individual (4.3%) had a moderate infection (108 OPG, eggs per gram of feces). The age of the sampled population ranged from six to 97 years, with a mean of 35.5 ± 18.1 years. There was no statistical relationship between infection and age (KK vs. AGE -0.442; HTX vs. AGE - 0.543). More than half of the participants were female (56.98%). The gender variable showed that men were more likely to become infected, according to KK (PR: 2.91) and HTX (PR: 1.79) data. The sensitivity of KK was 28.8% while that of HTX was 96.2%. The ROC curve showed that the probability of detecting schistosomiasis is higher with Helmintex (0.98) than with Kato-Katz (0.64). A HTX detects 3.3x more PPV and 25% more NPV. Public policies are necessary to change the panorama of neglected diseases, especially in the control of schistosomiasis in endemic areas.