The cases have been reported across four regions in England - the North East, Yorkshire, West Midlands and East Midlands.
According to HPA, to date, 267 cases of cryptosporidiosis have been confirmed in the affected areas since 11 May 2012, compared to 73 cases across the four regions for the whole of May 2011.
A multi-agency investigation is being carried out by HPA to determine whether these recent cases are linked. So far investigations have not identified a possible source of infection and the distribution of cases suggests it is unlikely that public water supplies are implicated.
Dr Stephen Morton, who is leading the investigation for the HPA, said that it is usual to see an increase in cryptosporidiosis cases in the early summer, but, the increase is higher than expected.
So HPA is working with NHS partners, local environmental health officers, the Drinking Water Inspectorate and the Food Standards Agency to see if there is a common source of infection, Morton added.
HPA noted that if the investigations identify a common source, it will issue further health advice to the public as necessary.
