Whooping cough is now spreading throughout Otago.
The outbreak started in Hawea late last month and there are now confirmed or suspected cases in Oamaru, Dunedin, Queenstown and Cromwell, Southern DHB medical officer of health Marion Poore says.
''It's not surprising - this is a highly infectious disease and people do travel. It does come in cycles from time to time and that's what we're seeing.''
As of late yesterday, Public Health South was aware of 25 confirmed cases. All but one were in the Wanaka and Hawea area and the other was in Oamaru. There were also six ''probable'' cases in Wanaka and Hawea and three in Cromwell.
In Wanaka and Hawea, half of the people diagnosed with whooping cough had not been immunised, or their vaccinations were not up to date, or they were adults who had been vaccinated but immunity waned about every 10 years, Dr Poore said.
The number of suspected cases throughout the province was now 174, 119 of those in children under the age of 15.
Dr Poore said the results of tests on a ''large proportion'' of the 174 suspected cases were still to be confirmed, so the ''number is probably going to rise.''
It took up to a week for samples to be analysed, depending on the type of test. One of the tests involved growing the organism ''which can take quite a few days because it's a difficult organism to grow.''
The other involved comparing the sample to a ''marker sample'' held by laboratories.
The number of suspected cases being reported to Public Health South by general practitioners remained ''steady''.
''There's always going to be a low level of cases in any community right around country and from time to time we will see an increase in particular communities.
''In terms of risk, the biggest concern we have is how can we protect our very young babies who have not had the chance to be vaccinated, because they're not quite old enough. Whooping cough can be a very serious illness for those tiny children.''
Dr Poore said, because it was ''very difficult'' to distinguish whooping cough from other common winter respiratory illnesses during the early stages, it was important people who were unwell stayed at home.
The DHB was urging people to be immunised, particularly women who were in their last trimester of pregnancy as it would give protection to both the mother and the baby during the first few months of the child's life, before vaccinations could be administered.
- Jessica Maddock
