Table 1 Case definitions

Index case

 The first case from a household identified in the surveillance system (person reported to a PHE/PHW surveillance system(s) following detection of Cryptosporidium in a faecal sample, with a specimen date in the study year)

Additional household case

 A person in a household of an index case, with self-reported similar symptoms (in questionnaire) that started within two weeks of the index case’s onset, with or without a Cryptosporidium positive stool sample

Asymptomatic carrier confirmed case

 A person in a household of an index case with: no reports of similar illness (in questionnaire); AND

 A Cryptosporidium positive stool sample