Abstract
ObjectivesIn 2010-2011, a waterborne outbreak of the parasite, Cryptosporidium hominis, affected approximately 27,000 inhabitants in the city of Östersund, Sweden. Previous research suggested that post-infectious symptoms, such as gastrointestinal symptoms and joint pain, could persist for up to two years after the initial infection. In this study, we investigated whether the parasite caused post-infectious sequelae for up to five years after the outbreak. This prospective cohort study examined whether individuals infected during the outbreak were more likely than uninfected individuals to report post-infectious symptoms five years later. The participants completed a questionnaire on whether they experienced a list of symptoms. We analysed data using logistic regression and calculated odds ratios with 95% confidence intervals.Results The analysis included 626 individuals. Among the 262 individuals infected during the outbreak, 56.5% reported symptoms at follow-up. Compared to uninfected individuals, infected individuals were significantly more likely to report watery diarrhoea, diarrhoea, swollen joints, abdominal pain, bloating, joint discomfort, acid indigestion, alternating bowel habits, joint pain, ocular pain, nausea, and fatigue at the follow-up, after adjusting for age and sex. Our findings suggested that cryptosporidiosis was mainly associated with gastrointestinal- and joint-related post-infectious symptoms for up to 5 years after the infection.