Two people in Havelock North are critically ill because of gastric illness believed to have been caused by bacterial contamination of the town's water supply, says the Hawke's Bay District Health Board.
The earlier death of a person at a local rest home may also be related to the contaminated water.
Pharmacies and medical centres in the town have been inundated with enquiries, and 40 sick people turned up at the Hastings Health Centre today.
Fifteen people reported to Hawke's Bay Hospital overnight with the campylobacter infection, and one person was admitted.
DHB chief executive Kevin Snee said two of the three rest homes in Havelock North had cases of gastric illness.
"There's two nursing homes that have some cases, we have two very sick people on intensive care, but we have no further deaths.
"We're not clearly going to give any personal details on these individuals, but they are elderly and they are very sick and they are in intensive care."
The only one of the three rest homes to respond to a request for comment, Duart, has told RNZ News none of its residents have gastric illness.
Two Havelock North pharmacies stayed open today to provide support.
The part-owner and director of one of them, Ross Denton said dozens of people had come through the doors and the pharmacy would have sold 20 - 30 prescriptions today, with almost all of them for gastric problems.
The Hastings District Council is still investigating how the bug got into the water, but said it may be related to heavy storms and surface flooding last week.
Yesterday the Hawke's Bay District Health Board (DHB) said 24 people had been admitted to hospital since Friday night.
The DHB has confirmed that the illnesses stemmed from contamination in the water supply, though the cause of that contamination is not yet known. It could not confirm whether the death at the nursing home was caused by drinking contaminated water.
Two schools close temporarily
Two private girls' boarding and day schools in the area have closed temporarily: Iona College and Woodford House.
Iona College principal Shannon Warren said up to a third of the school's students and staff had continued to report ill health across the weekend due to the gastro outbreak.
"The Board of Trustees in conjunction with our Senior Management Team have made the difficult decision to close the Boarding House and the Day School from 7.00pm this evening.
"We are obviously in a unique situation compared to other local schools because we are a residential facility with more than half our students boarding."
Ms Warren said Iona College would re-open on Tuesday at 4pm for Boarders and the Day School would re-open Wednesday morning.
She said the Hastings District Council was on site flushing the school's water pipes to bring the chlorine through, however the "boil water" notice was still in place.
Woodford House, another boarding and day school in Havelock North, said a large number of girls and some staff were sick with the infection and it would stay closed for two days.
The boil water notice for Havelock North residents remains in place today, but the DHB said chlorination of the entire Havelock North water supply seems to have been effective.
Medical Officer of Health Nick Jones said testing of sick people has confirmed that most of the illness being reported was campylobacter infection.
He said the boil water notice would remain until the DHB was confident there was no other bug resistant to chlorine in the water, and that was expected to take several days.
The general advice being given is that campylobacter cannot be spread through the air, but it can be spread if people swallow the bacteria. This makes it possible to contract the disease from contaminated water and food, or from contact with infected people, so hand washing is extremely important.
Hands need to be washed thoroughly, using plenty of soap, cleaning under fingernails, rinsing well and drying on a clean towel.
- before and after preparing food
- after going to the toilet or changing a baby's nappy
- after caring for people with campylobacter infection
- after playing or working with animals
Hastings District Council Mayor Lawrence Yule has apologised for the outbreak.
"This is the first time that I can recall, or significant records show, that we've had a waterborne illness in part of our district.
"I and my councillors are pretty distressed about this and apologise to all the people who are held up, laid up in bed and all the inconvenience that that has caused.
"We actually don't know how this has happened. We are charged with delivering our residents safe drinking water and clearly that hasn't happened, and I and others have to take some responsibility for that."
He said the key focus was to find out how it happened and to prevent if from ever happening it again.
"We don't treat our water in Hastings because it's pristine. It comes from an aquifer. It's pumped out of the ground and apart from adding fluoride in, is untreated, so somehow we are getting a pristine level of water contaminated with something and we're trying to get to the bottom of what that is."
The bore which drew the water from that aquifer may be responsible, Mr Yule said.
He confirmed there was surface flooding after the storms last week and said that if indeed the bore was the issue, the council may have to look at relocating their water drawdowns elsewhere.
Hawke's Bay DHB has confirmed that the symptoms associated with campylobacter infection, such as diarrhoea, vomiting, fever and pain were all experienced by those reporting a gastric illness.