BUGGED: Campylobacter bacteria are the number-one cause of food-related gastrointestinal illness. NZ has the world's highest rate of campylobacter disease. (US Department of Agriculture)
Studies show that New Zealand has the world's highest rates of campylobacter disease. A report from Otago University's health researchers say that New Zealand's rate of campylobacter cases is 30 times higher than the United States rates, and three times more than Australia.
There are approximately 800 hospitalisations through campylobacteriosis a year in New Zealand. Characterised by headaches, fever and watery or bloody diarrhoea, campylobacter is a bacterial organism that causes the gastro-intestinal disease campylobacteriosis when it lodges in the walls of the intestine (NZ Food Safety Authority).
There were 16,000 reported cases of campylobacteriosis reported in 2006, but evidence suggests there could be around 160,000 cases, as most people do not seek medical help.
Fresh poultry accounts for 50 percent of the reported cases of the disease, but experts believe that other sources could be more significant than previously thought.( Lamb sold to the US) (BEEF Trim Sold to the US)
Christchurch microbiologist Ben Harris says there is strong evidence linking run-off from dairy farms into waterways causing faecal contamination including campylobacter.
Mr Harris believes that as far as hygiene is concerned, New Zealanders have been lulled into a false sense of security.
"Over the last 30 years the population has doubled or more, we have tidied up our sewerage dramatically, but the animal population has grown hugely and people think that 'it is only animals' so it doesn't matter so much."
"There is something like 5.4 million dairy cattle in New Zealand and they defecate the equivalent of over 70 million people every day on the land."
Many people do not realise that healthy animals carry pathogens such as giardia, salmonella, cryptosporidium and campylobacter - which people do not carry, Mr Harris says.
Dairy farms alongside waterways are a major source of campylobacter in rivers, lakes and pools.
"It's the run-off - each gram of faeces is about a million bacteria – so if you have got an animal that produces 5 kgs of faeces - that's vast number."
Normally, those bugs will die off quickly, Mr Harris says, but where there is moisture such as rain or irrigation, they can live for weeks or months and are eventually washed into the waterways.
In Canterbury, an increasing number of farms are being converted to intensive dairy units with a need for irrigated water.
Samples of E.coli, a bacterial indicator of campylobacter, in South Island rivers show no campylobacter at the river source in the Alps but as the river approaches the coastline the E. coli level rises systematically.
A study carried out in the Whatawhata region, published in the New Zealand Journal of Marine and Freshwater Research in 2004, showed E.coli levels in pastoral streams were too high even for stock drinking.
Streams along pastoral grazing areas had the most elevated levels of E.coli. Streams in areas where land use had changed from pastoral farming to forestry saw an immediate fall in E.coli contamination.
Senior scientist for National Institute of Water & Atmospherics (NIWA), Graham McBride, says scientists do not have the answer about the link between the dairy industry and campylobacter.
"Over the next couple of years we have got a national team looking at modelling the whole campylobacter cycle and that is one issue for consideration of course".
"What we need to be able to do ...(is) figure out the genetic campylobacter species that are turning up in human specimens."
The high levels of campylobacter have a high cost on the health system, and could affect our agricultural produce and tourist industry, which depend on New Zealand's "clean green" image, according to a research plan put forward by the Enteric Zoonotic Disease Modelling Group.
Mr McBride is one of several scientists taking part in group, which aims to "identify the link between human health and the environment", by tracking the transmission paths of campylobacter in a three-year research programme.
"Human illness with enteric zoonotic pathogens occurs as a result of contamination of our environment, animals, water and food with faecal material. More effective controls are needed."
A 2005 Annual Review of drinking water from the Ministry of Health showed that 76 percent of New Zealanders were served by community water that complied with E. coli regulations.