Unprecedented diarrheal outbreak erupts in UK as cases spike 3x above usual

Enlarge / A sign directing people to a toilet facility during the Children's Day Parade, part of the Notting Hill Carnival celebration in west London on Sunday August 27, 2023. (credit: Getty | Yui Mok)

The United Kingdom is experiencing a dramatic outbreak—unprecedented in scale and magnitude—of diarrheal illnesses from the intestinal parasite, Cryptosporidium, aka Crypto.

According to a rapid communication published Thursday in the journal Eurosurveillance, UK health officials report that Crypto cases have exceeded the upper bounds of expected cases since mid-September, and an October peak saw cases roughly threefold above what is usual for this time of year. The outbreak is still ongoing.

Laboratory notifications of Cryptosporidium species in England, Wales, and Northern Ireland, by week of specimen, 2023. (credit: Eurosurveillance | Peake et al.)

So far, it's unclear what's driving the extraordinary burst in cases. The outbreak has splattered into almost every region of all four UK nations. "Given the scale and geographical spread of the [case] exceedance across regions and nations of the UK, a single local exposure is an unlikely cause," the authors, led by officials at the United Kingdom Health Security Agency in London, wrote in the rapid report.