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RESEARCH PRODUCT

Reduced prevalence of soil-transmitted helminths and high frequency of protozoan infections in the surrounding urban area of Curitiba, Paraná, Brazil

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Human populations living in the surrounding urban areas of large Brazilian cities have increased vulnerability to intestinal parasites. However, the epidemiological scenario of soil-transmitted helminths (STH) in Curitiba, Paraná's main city, remains largely unknown. To bridge this gap of knowledge, this study aims to determine the prevalence of intestinal parasites and to investigate potential transmission pathways of the most prevalent species detected. We conducted a cross-sectional epidemiological study between July and September 2014 among schoolchildren in urban and peri-urban (deprived) areas of the municipality of Campo do Tenente, Curitiba. A total of 549 stool samples were used for coproparasitological diagnosis. Microscopy-positive samples of the most common species found were re-assessed by PCR and sequencing methods at the small subunit rRNA gene. Prevalence of infection by any given enteroparasite was 24.8%, but soil-transmitted helminths were only detected in 3.5% of the examined samples. Frequency of protozoan infections reached 90% and 97.8% in single and multiple infections, respectively. Blastocystis sp. (38.9%) was the most frequently species found in the surveyed schoolchildren population. A total of 41 Blastocystis-positive samples were unambiguously typed as ST1 (36.4%), ST2 (21.2%), ST3 (39.4%), and ST1 + ST3 mixed infection (3.0%). These results indicate that Blastocystis transmission is primarily anthroponotic in origin. This data highlights the importance of maintaining the anthelminthic control programs currently in place and of improving sanitary disposal of human excreta in poor-resource settings. CAPES for Camila Yumi Oishi scholarship. Third author was the recipient of a fellowship (Erasmus Mobilitat Internacional de Doctorat 2014–2015) co-financed by the Valencia University and the programme ERASMUS+ of the European Union; UFPR Office for Extension and Culture (PROEC) and by the Brazilian Extension Program for Universities (ProExt); PROMETEO2014-083 Fase II from Conselleria d’Educació, Investigació, Cultura i Esport de la Generalitat Valenciana (Valencia, Spain) and by No. RD16/0027/0023, Red de Investigación Cooperativa en Enfermedades Tropicales-RICET, IV National Program of I+D+I 2017–2021, ISCIII-Subdirección General de Redes y Centros de Investigación Cooperativa from the Ministerio de Sanidad y Consumo (Madrid, Spain); additional funding was also provided by the ISCIII under Project CP12/03081. Sí