Epidemiology of Strongyloides stercoralis in northern Italy: results of a multicentre case-control study, February 2013 to July 2014

• Published in: Euro surveillance : bulletin européen sur les maladies transmissibles Vol. 21; no. 31; p. 1
• Main Authors: Buonfrate, Dora, Baldissera, Mara, Abrescia, Fabrizio, Bassetti, Matteo, Caramaschi, Giacomo, Giobbia, Mario, Mascarello, Marta, Rodari, Paola, Scattolo, Novella, Napoletano, Giuseppina, Bisoffi, Zeno
• Format: Journal Article
• Language: English
• Published: Sweden Centre Europeen pour la Surveillance Epidemiologique du SIDA (European Centre for the Epidemiological Monitoring of AIDS) 04.08.2016; European Centre for Disease Prevention and Control (ECDC)
• Subjects: Adolescent; Adult; Age Distribution; Aged; Aged, 80 and over; Animals; Antibodies, Helminth - blood; Case-Control Studies; Emigrants and Immigrants - statistics & numerical data; Enzyme-Linked Immunosorbent Assay; Eosinophilia - epidemiology; Epidemiology; Feces - parasitology; Female; Humans; Italy - epidemiology; Male; Medical diagnosis; Middle Aged; Noncitizens; Parasites; Prevalence; Regression Analysis; Risk assessment; Sentinel Surveillance; Sex Distribution; Strongyloides stercoralis - isolation & purification; Strongyloidiasis - blood; Strongyloidiasis - diagnosis; Strongyloidiasis - epidemiology; Young Adult; Italy; Epidemiology; parasitic disease; Strongyloides stercoralis
• ISSN: 1560-7917; 1025-496X; 1560-7917
• DOI: 10.2807/1560-7917.ES.2016.21.31.30310

Strongyloides stercoralis is a soil-transmitted helminth widely diffused in tropical and subtropical regions of the world. Autochthonous cases have been also diagnosed sporadically in areas of temperate climate. We aimed at defining the epidemiology of strongyloidiasis in immigrants and Italians living in three northern Italian Regions. Screening for S. stercoralis infection was done with serology, confirmation tests were a second serological method or stool agar culture. A case-control approach was adopted and patients with a peripheral eosinophil count ≥ 500/mcL were classified as cases. Of 2,701 individuals enrolled here 1,351 were cases and 1,350 controls; 86% were Italians, 48% women. Italians testing positive were in 8% (97/1,137) cases and 1% (13/1,178) controls (adjusted odds ratio (aOR) 8.2; 95% confidence interval (CI): 4.5-14.8), while positive immigrants were in 17% (36/214) cases and in 2% (3/172) controls (aOR 9.6; 95% CI: 2.9-32.4). Factors associated with a higher risk of infection for all study participants were eosinophilia (p < 0.001) and immigration (p = 0.001). Overall, strongyloidiasis was nine-times more frequent in individuals with eosinophilia than in those with normal eosinophil count.