A large number of elderly people have still not recovered from last year's campylobacter outbreak in Havelock North, the inquiry panel investigating the event heard yesterday.
Speaking about the health authority's response to the outbreak, Hawke's Bay District Health Board medical officer of health Nick Jones said that anecdotal information showed that the health of a large number of elderly people had deteriorated significantly in the wake of falling ill in August.
"They've deteriorated in their ability to cope at home, they have never really recovered."
He added that there were still implications for those who contracted campylobacter in terms of the long-term impact on people's gastro-intestinal function, and issues such as reactive arthritis.
"There are still many scientific questions left unanswered. We want to document these concerns, and they will be further investigated."
He said the DHB had sent a proposal to the Health Research Council for studies to be carried out on such issues.
Dr Jones also noted that a more formalised system of schools reporting absenteeism to health authorities would be useful in such situations.
A leading indicator that the contamination was widespread, but localised, came through the findings that filtered through that local schools had an unusually high degree of absenteeism at the start of the outbreak - about 15 to 20 per cent.
"This information was an ad hoc way of finding out what was going on," Dr Jones said.
"Schools notify the Ministry of Education and then the health authorities, but if schools had a national database with this information and if it was possible for that to be adapted to be able to detect unusual increases in absenteeism that would be good."
He said that no one had expected the extent of people who would fall ill, numbering more than 5000.
"This case was unique - people would have been exposed over multiple days in many cases, and that might have contributed to there being more illness than expected."
Throughout the inquiry process there has been reference to the tension between the agencies involved in ensuring drinking water safety - especially the Hawke's Bay Regional Council and Hastings District Council.
Yesterday Hawke's Bay DHB chairman Kevin Snee, Hawke's Bay Regional Council chief executive Andrew Newman and Hastings District Council chief executive Ross McLeod issued a joint memorandum to the inquiry where they promised to improve working relationships when it came to drinking water.
"It is clear to us that the inquiry has directed significant attention to these issues. We predict that the inquiry will make recommendations that call for strengthening of working relationships, collaboration and information sharing between key agencies," the memorandum said.
On Wednesday this week, a meeting was held to affirm the commitment of the agencies to work better together.
In addition to the memorandum signatories, the meeting was attended by CHB District Council, Napier City Council and Ngati Kahungunu Iwi Incorporated representatives.