Infectious disease rates in Otago and Southland skyrocketed last year and the region had the largest number of cases in New Zealand health board region for two quarters running.
A report released last month showed the Southern District Health Board (SDHB) had the largest number of recorded cases in the country for the July to September quarter last year.
This was the second quarter in a row the area topped the country and in the six-month period from April last year there were 931 cases of infectious diseases in the SDHB region, from a total of 54 outbreaks.
Most of the outbreaks were of norovirus (29), the symptoms of which include nausea, forceful vomiting and watery diarrhoea and gastroenteritis (21), which has symptoms including a combination of diarrhoea, vomiting and abdominal pain.
That was more cases than in the Auckland region in the same period (629), which has five times the SDHB region's population.
Southern District Health Board Medical Officer of Health Dr Marion Poore said while there was a larger number of cases than usual, it was normal for outbreaks to increase over winter.
''These outbreaks occurred mainly in rest-homes but also in early child-care centres and a small number in hospital wards.''
Due to many of the outbreaks occurring in rest-homes it was possible they resulted in deaths over the period.
''While deaths did occur in rest-homes over this period, we're unable to confirm if any were directly caused by a gastroenteritis illness.
''It is well recognised that an acute illness such as gastroenteritis may adversely affect frail people,'' she said.
The number of cases over the period was tough on staff, particularly in rest-homes.
''There is no doubt that staff caring for residents of rest-homes when there is an outbreak find it a very tiring experience.''
Most places dealt with outbreaks well and were good at at getting them under control quickly.
The high number of cases highlighted the importance good hygiene practices, staff training around early recognition of an outbreak and promptly putting in control measures, such as excluding those who are sick.
The numbers of outbreaks had reduced ''markedly'' since August and the most recent one was reported last month.
Among outbreaks reported on by the Otago Daily Times last year were an outbreak of gastroenteritis among staff and residents at Ross Home and Hospital in May, which caused the facility to go into lockdown.
An outbreak of norovirus and Clostridium difficile also affected parts of Dunedin Hospital in May, closing ward 6A.
University of Otago infectious disease specialist Prof Stephen Chambers, of Christchurch, said the spike in cases was likely no cause for alarm.
''I doubt there is anything really mischievous going on in the southern area.''
It was usual for spikes to be followed by quiet periods, as levels of immunity among those susceptible fluctuated.
