19 Aug 2016

Timeline: NZ's worst waterborne outbreak

5:20 pm on 19 August 2016

More than 4000 people in Havelock North have been brought down with gastric illness - New Zealand's worst-ever waterborne disease outbreak.

The outbreak might also have killed a person, after test results confirmed an elderly woman who died last week had contracted campylobacter.

The Hawke's Bay District Health Board said it was not clear yet whether the infection caused or contributed to the 89-year-old's death, but the coroner had opened an inquiry.

The government and the Hastings District Council have also announced possible financial relief for the town.

Revenue Minister Michael Woodhouse said Cabinet would consider letting Inland Revenue waive interest on late tax payments for businesses affected by the outbreak.

And Hastings Mayor Lawrence Yule said the council would give $10,000 to the Havelock North Business Association to attract visitors to the town.

It is the latest development in a public health crisis that has now affected the small Hawke's Bay town for over a week.

How it unfolded

October 2015

The Hastings District Council closes the number three bore at the Brookvale bore field indefinitely after E coli contamination. Bore three is one of three bores that supplies water to Havelock North from the Te Mata aquifer.

The council begins an investigation into what caused the contamination. Bores one and two continue to draw water.

Tuesday, 9 August 2016

Standard water tests - which the Hastings District Council conducts every two days - come back clear of any contamination.

Thursday, 11 August

Havelock North schools start to notice large numbers of students absent. About 120 Te Mata School pupils call in sick, three quarters of them due to stomach illness.

The Hastings District Council conducts another routine water test. Results are expected the next morning.

Friday, 12 August

People continue to become ill, with some heading to hospital.

Water test results received about 10.30am are suspicious. The Hawke's Bay DHB calls schools and confirms large numbers of absences. Hastings Mayor Lawrence Yule is not informed until about five hours later - he makes a decision to chlorinate the water.

Later that afternoon, the council decides to also issue a 'boil water' notice, and starts informing the media and public from about 6pm.

Saturday, 13 August

Confirmed test results show bores one and two at the Brookvale bore field are contaminated.

The DHB confirms that an elderly woman living at a resthome has died of a gastric illness but says it does not know if the death was caused by drinking contaminated water.

Dozens of people are now arriving at hospital with gastric illness, with eight taken to the emergency department.

Sunday, 14 August

Two people become critically ill. Boarding schools in the area decide to send pupils home and close for several days.

Testing shows most people who are sick are infected with campylobacter. Officials continue to investigate the cause of the contamination.

Monday, 15 August

The DHB says 280 gastroenteritis notifications were received over the weekend and it suspects there are many more cases that have not been notified. It estimates the total number of cases as up to 2000. The contamination might be from animal faeces entering the water supply, it says.

With hundreds of pupils still absent, all schools in Havelock North decide to close for at least two days.

Hastings Mayor Lawrence Yule publicly apologies for the "horrific" outbreak and says there will be an independent inquiry into how the contamination happened.

Residents and some councillors start to question why they were not informed earlier on Friday when the suspicious test result first came back.

Tuesday, 16 August

The DHB keeps a 'boil water' notice in place, saying it still has not ruled out the presence of cryptosporidium in the water, which cannot be treated with chlorine.

Nine tankers of fresh water are parked in strategic places around Havelock North for residents to fill bottles from, while the Red Cross visits hundreds of homes to deliver supplies such as toilet paper and nappies.

Thursday, 18 August

The government announces it will hold its own independent inquiry into the contamination.

Meanwhile, one of the tankers brought in to provide people with clean water returns an E coli indicator - later found to be a false positive. However, on the day, the council extends chlorination to all of Hastings' water supply as well.

The Hastings District Council releases the results of an investigation into the 2015 contamination of Brookvale bore three. Part of the investigation looked at a nearby piggery and a mushroom farm, but the report was inconclusive.

Secondary schools re-open but primary schools say they will stay shut for the rest of the week. Restaurant and cafe owners in Havelock North say they're considering a class action to recover losses caused by the outbreak.

Friday, 19 August

The Hawke's Bay DHB revises its estimate of case numbers upwards to 4100. It also confirms the 89-year-old woman who died last week had campylobacter, but it is too early to say whether the infection caused or contributed to her death. The Hawke's Bay coroner opens an inquiry.

The DHB also says the campylobacter bacteria could have started to incubate in humans as early as 5 August - a week before authorities announced the water supply was contaminated. Very heavy rain fell that day and the following day, which has been one of the theories put forward as the cause of the contamination. However, officials still cannot confirm the source of contamination.

The latest tests of Hastings' and Flaxmere's water supply show there is no contamination and residents no longer need to boil their drinking water.

The Hastings District Council says, however, the area's water supply will be chlorinated until further notice.

The E Coli scare in tanker water delivered to Havelock North turns out to be unfounded.