FioSchisto's expert perspective on implementing WHO guidelines for schistosomiasis control and transmission elimination in Brazil.

The World Health Organization (WHO) recognizes schistosomiasis as one of the Neglected Tropical Diseases targeted for global elimination in the 2030 Agenda of the Sustainable Development Goals. In Brazil, schistosomiasis mansoni is considered a public health problem, particularly prevalent among vulnerable populations living in areas with poor environmental and sanitary conditions. In 2022, the WHO published a Guideline encompassing recommendations to assist national programs in endemic countries in achieving morbidity control, eliminating schistosomiasis as a public health problem, and advancing towards interrupting transmission. The perspectives presented here, collectively prepared by members of the Oswaldo Cruz Foundation's (Fiocruz) Schistosomiasis Translational Program (FioSchisto), along with invited experts, examine the feasibility of the WHO recommendations for the Brazilian settings, providing appropriate recommendations for public health policies applicable to the epidemiological reality of Brazil, and suggests future research to address relevant issues. In Brazil, the provision of safe water and sanitation should be the key action to achieve schistosomiasis elimination goals. The agencies involved in measures implementation should act together with the Primary Care teams for planning, executing, monitoring, and evaluating actions in priority municipalities based on their epidemiological indicators. Host snails control should prioritize judicious ecological interventions at breeding sites. The Information, Education, and Communication (IEC) strategy should be associated with water and sanitation and other control actions, actively involving school community. To identify infected carriers, FioSchisto recommends a two-stage approach of immunological and molecular tests to verify transmission interruption during the intervention and beyond. Praziquantel administration should be done under medical supervision at the Primary Care level. MDA should be considered in exceptional settings, as a measure of initial attack strategy in locations presenting high endemicity, always integrated with water and sanitation, IEC, and snail control. To assist decision-making, as well as the monitoring and evaluation of strategic actions, there is a need for an Information System. FioSchisto considers this systematization essential to make investments in strategic research to support the improvement of schistosomiasis control actions. Efforts toward schistosomiasis elimination in Brazil will succeed with a paradigm shift from the vertical prescriptive framework to a community-centered approach involving intersectoral and interdisciplinary collaboration.

Synthetic peptides as an antigenic base in an ELISA for laboratory diagnosis of schistosomiasis mansoni.

A pool of five synthetic peptides was used as an antigenic base in an ELISA (ELISA-Pp) for laboratory diagnosis of Schistosoma mansoni. Serum samples were obtained from individuals with acute (n=23) and chronic (n=30) schistosomiasis, with other parasitoses (n=39) or without parasitic infections (n=100). ELISA-Pp was compared with other immunoenzymatic methods for detection of IgM (IgM-ELISA) or IgG (IgG-ELISA) as well as an immunofluorescence test for detection of IgM antibodies (IgM-IFT). The sensitivity and specificity of ELISA-Pp was 86.8% and 94.2% when tested on the schistosomiasis group and the non-schistosomiasis group, respectively. Comparison of ELISA-Pp with other serological methods resulted in kappa concordance indices varying from 0.59 to 0.75. Evaluation of anti-peptide IgG antibodies showed higher levels in patients with acute compared with chronic schistosomiasis (P=0.001). ELISA-Pp showed satisfactory sensitivity and high specificity and may constitute a potentially useful method for laboratory diagnosis of schistosomiasis mansoni.

Comparative evaluation of direct agglutination test, rK39 and soluble antigen ELISA and IFAT for the diagnosis of visceral leishmaniasis.

Five serological tests for the diagnosis of visceral leishmaniasis (VL) were compared: a direct agglutination test (DAT) based on freeze-dried antigen (DAT-fd); a locally produced DAT (DAT-LPC); an IgG ELISA against rK39 (ELISA-rK39); an IgG ELISA for Leishmania chagasi (ELISA-L. chagasi); and an IgG IFAT against L. chagasi. Serum samples from 88 patients with VL, 20 non-infected individuals and 85 patients with others infectious diseases were evaluated. The sensitivity rates were: DAT-fd, 96.6%; DAT-LPC, 95.5%; ELISA-rK39, 88.6%; ELISA-L. chagasi, 89.8%; and IFAT, 92.0% (P>0.05). The specificity for the control groups varied from 53.3% to 100%. DAT-fd had the highest efficiency (97.4%), followed by DAT-LPC (91.7%) and ELISA-rK39 (90.7%). Our data suggest that DAT-fd, DAT-LPC and ELISA-rK39 are useful tests for the diagnosis of VL and could replace IFAT as the routine diagnostic test in Brazil.

Schistosomiasis mansoni: follow-up of control program based on parasitologic and serologic methods in a Brazilian community of low endemicity.

A field survey on schistosomiasis was carried out in 1998, in the municipality of Pedro de Toledo, a low endemic area in the state of São Paulo, Brazil. According to the parasitologic Kato-Katz method, the prevalence rate was 1.6%, with an infection intensity of 40.9 eggs per gram of stool. By the immunofluorescence test (IFT) for detection of IgG and IgM antibodies in the serum, IgG-IFT and IgM-IFT, respectively, prevalence indices of 33.2% and 33.5% were observed. To assess the impact of the schistosomiasis control program in the area, parasitologic and serologic data obtained in 1998, analyzed according to the age, sex, and residence zone, were compared to previous data obtained in a epidemiologic study carried out in 1980, when prevalence indices were of 22.8% and 55.5%, respectively by Kato-Katz and IgG-IFT. A significant fall of the prevalence was observed, indicating that the control measures were effective. Nonetheless, residual transmission was observed, demonstrating the need for a joint effort to include new approaches for better understanding the real situation and improving the control of the disease in low endemic areas.

[IgM-ELISA for diagnosis of schistosomiasis mansoni in low endemic areas]. / ELISA-IgM para diagnóstico da esquistossomose mansoni em área de baixa endemicidade.

An immunoenzymatic method for the detection of IgM antibodies (IgM-ELISA) against a fraction of Schistosoma mansoni adult worm antigen, soluble in trichloroacetic acid (TCA-soluble fraction), was evaluated for epidemiological purposes in low endemic areas for schistosomiasis. Blood samples on filter paper were collected from a population living in the municipality of Pedro de Toledo, São Paulo State, and submitted to IgM-ELISA. The results were compared to those obtained by the IgM-immunofluorescence test (IgM-IFT) and the Kato-Katz parasitological method. Positive rates of 36.8%, 33.5%, and 1.6% were obtained respectively by the IgM-ELISA, IgM-IFT, and Kato-Katz methods. The geometric mean obtained by the parasitological method was 40.9 eggs per gram of feces (epg). The nearly perfect agreement observed between the two serological tests (Kappa index of 0,89) indicates good diagnostic performance by the evaluated test. IgM-ELISA is a potentially useful method for diagnosis of schistosomiasis in individuals with low worm burden.