title: Retrospective cohort study of an outbreak of cryptosporidiosis caused by a rare Cryptosporidium parvum subgenotype.
abstract: The occurrence of a gastrointestinal illness among a class of 96 undergraduate veterinary students in New Zealand prompted laboratory and questionnaire-based investigations. Cryptosporidium parvum was the only enteropathogen identified in 4/7 faecal specimens analysed. The C. parvum isolates carried a rare IIa GP60 allele, indicating a point-source outbreak. The infection source could not be microbiologically traced, but the investigation suggested contact with calves during a practical class as the most likely exposure. A total of 25/80 respondents to a questionnaire were defined as cases using a clinical case definition (31% attack rate). The inferred median incubation period was 5 days (range 0-11 days), and the median illness duration was 5-6 days (range 2-23 days), corroborating previous observations in experimental cryptosporidiosis. Disease was self-limiting, characterized by abdominal discomfort, diarrhoea, and in some cases, vomiting. Originating from a rural area and having had previously handled ruminants were associated with a significant risk reduction in males. All the three students who reported chronic use of steroid inhalers for treatment of asthma were cases. This case highlighted, once again, the potential hazard for explosive outbreaks of cryptosporidiosis.
authors.affiliation: Massey University, Institute of Veterinary, Animal and Biomedical Sciences, Palmerston North, New Zealand. a.grinberg@massey.ac.nz
authors.forename: A
authors.initials: A
authors.lastname: Grinberg
authors.forename: W E
authors.initials: WE
authors.lastname: Pomroy
authors.forename: R A
authors.initials: RA
authors.lastname: Squires
authors.forename: A
authors.initials: A
authors.lastname: Scuffham
authors.forename: A
authors.initials: A
authors.lastname: Pita
authors.forename: E
authors.initials: E
authors.lastname: Kwan
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D002417:Cattle; D015331:Cohort Studies; D003457:Cryptosporidiosis / Q000453:epidemiology* / Q000469:parasitology / Q000473:pathology; D016785:Cryptosporidium parvum / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D004196:Disease Outbreaks; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D017720:Molecular Epidemiology; D009520:New Zealand / Q000453:epidemiology; D015800:Protozoan Proteins / Q000235:genetics; D012189:Retrospective Studies; D012582:Schools, Veterinary; D013334:Students; D011795:Surveys and Questionnaires; D013997:Time Factors; D055815:Young Adult
chemical_list: D015800:Protozoan Proteins