Ascaris lumbricoides eggs or artefacts? A diagnostic conundrum

Due to the presence of artefacts in stool samples, the copromicroscopic diagnosis of Ascaris lumbricoides is not always straightforward, particularly in the case of fertilized decorticated eggs. A total of 286 stool samples from 115 schoolchildren in India and 171 adult immigrants in Italy were screened for the presence of A. lumbricoides eggs by both Kato-Katz thick smear and Mini-FLOTAC. If the outer layer of A. lumbricoides eggs was absent, two aliquots of each stool sample were preserved: one for coproculture to identify larvae after development and one to compose a pool of stool for molecular analysis. A total of 64 stool samples (22.4%) were positive for A. lumbricoides using the Kato-Katz thick smear; 36 (56.3%) of these showed mammillated A. lumbricoides eggs, 25 (39.1%) showed elements resembling fertilized decorticated eggs, while three samples (4.7%) showed both mammillated and decorticated eggs. By Mini-FLOTAC, 39 stool samples (13.6%) were positive, while decorticated A. lumbricoides-like eggs were identified as artefacts. These results were confirmed by negative coprocultures and quantitative polymerase chain reaction. Mini-FLOTAC can be used for a reliable diagnosis of A. lumbricoides, thanks to the flotation and translation features which allow a clearer view, resulting in the correct identification of A. lumbricoides eggs.Fil: Maurelli, Maria Paola. Università degli Studi di Napoli Federico II; ItaliaFil: Alves, L. C.. Universidad Federal Rural Pernambuco; BrasilFil: Aggarwal, C. S.. National Centre for Disease Control; IndiaFil: Cociancic, Paola. Università degli Studi di Napoli Federico II; Italia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Levecke, B.. University of Ghent; BélgicaFil: Cools, P.. University of Ghent; BélgicaFil: Montresor, A.. Organizacion Mundial de la Salud; SuizaFil: Ianniello, D.. Università degli Studi di Napoli Federico II; ItaliaFil: Gualdieri, L.. Centro per la Tutela della Salute degli Immigrati; ItaliaFil: Cringoli, G.. Università degli Studi di Napoli Federico II; ItaliaFil: Rinaldi, Laura. Università degli Studi di Napoli Federico II; Itali