Abstract
In this Briefing we summarise findings from our recent study into the link between severe weather events and clusters of the gastrointestinal disease cryptosporidiosis in Aotearoa New Zealand (NZ). We found statistical evidence that weather events with heavy rainfall or flooding may play a role in the development of some outbreaks of this infectious disease. This finding is consistent with other NZ and international evidence, though additional research is needed to further clarify this relationship. This is especially so since rainfall intensity is expected to keep rising in NZ due to climate change. This study provides yet further support for the need to protect drinking water supplies and recreational water from contamination with pathogens, especially from agricultural runoff and sewage leaks from broken pipes. The Government's current plans to weaken drinking water protections should be discouraged. Cryptosporidium are microscopic parasites that can cause gastrointestinal pain, diarrhea, vomiting and fever with symptoms usually lasting one to two weeks. They are common cause of waterborne outbreaks of infectious intestinal disease in NZ.