Swimming pool-related outbreak of a rare gp60 subtype of cryptosporidium hominis, England, october 2016

Helen Bagnall, Rachel M. Chalmers, Michelle Henderson, Stewart Sorrell, Guy Robinson, Kristin Elwin, Gayle Dolan*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review


    In October 2016, Public Health England was initially notified of four cases of cryptosporidiosis among users of two swimming pools. We investigated to identify further cases, the outbreak source, and ensure the implementation of appropriate control measures. Probable primary cases had diarrhoea and reported swimming in the pools 1–12 days prior to illness; confirmed cases were verified by the reference laboratory. Secondary cases had contact with primary cases 1–12 days prior to illness. We identified twenty-two cases: eleven were primary (eight confirmed) and eleven were secondary (five confirmed). Four cases were infected with C. parvum (different gp60 subtypes); all were primary and swam at two pools. Seven primary and secondary cases were infected with C. hominis gp60 subtype IdA16, and all were associated one pool. Failings in pool water treatment and management were identified that likely contributed to the load on the filters and their efficiency. Our investigation identified a complex outbreak, with secondary transmission, involving exposures to two swimming pools. C. hominis IdA16 is rare; it has been isolated from only three previous UK cases. We hypothesize that C. hominis cases arose from a common exposure, and the C. parvum cases were likely sporadic. This investigation highlights the value of integrating epidemiology and microbiology to investigate clusters of Cryptosporidium cases, defining the extent of the outbreak and the likely transmission pathways.

    Original languageEnglish
    Article number3152
    Number of pages12
    JournalWater (Switzerland)
    Issue number22
    Publication statusPublished - 1 Nov 2021

    Bibliographical note

    Publisher Copyright:
    © 2021 by the authors. Licensee MDPI, Basel, Switzerland.


    • Cryptosporidium
    • Gp60
    • Outbreaks
    • Swimming pools
    • Typing


    Dive into the research topics of 'Swimming pool-related outbreak of a rare gp60 subtype of cryptosporidium hominis, England, october 2016'. Together they form a unique fingerprint.

    Cite this