Health sequelae of human cryptosporidiosis-a 12-month prospective follow-up study.

To investigate long-term health sequelae of cryptosporidiosis, with especial reference to post-infectious irritable bowel syndrome (PI-IBS). A prospective cohort study was carried out. All patients with laboratory-confirmed, genotyped cryptosporidiosis in Wales, UK, aged between 6 months and 45 years of age, over a 2-year period were contacted. Five hundred and five patients agreed to participate and were asked to complete questionnaires (paper or online) at baseline, 3 and 12 months after diagnosis. The presence/absence of IBS was established using the Rome III criteria for different age groups. Two hundred and five of 505 cases completed questionnaires (40% response rate). At 12 months, over a third of cases reported persistent abdominal pain and diarrhoea, 28% reported joint pain and 26% reported fatigue. At both 3 and 12 months, the proportion reporting fatigue and abdominal pain after Cryptosporidium hominis infection was statistically significantly greater than after C. parvum. Overall, 10% of cases had sufficient symptoms to meet IBS diagnostic criteria. A further 27% met all criteria except 6 months' duration and another 23% had several features of IBS but did not fulfil strict Rome III criteria. There was no significant difference between C. parvum and C. hominis infection with regard to PI-IBS. Post-infectious gastrointestinal dysfunction and fatigue were commonly reported after cryptosporidiosis. Fatigue and abdominal pain were significantly more common after C. hominis compared to C. parvum infection. Around 10% of people had symptoms meriting a formal diagnosis of IBS following cryptosporidiosis. Using age-specific Rome III criteria, children as well as adults were shown to be affected.