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Cool, clear and nasty

Bush lovers are given to drooling over the taste of cool, clear stream water. It's the mark of the New Zealand outdoors - at least it was. But just how clean is it now? ALISTAIR HALL investigates

Just how great is natural New Zealand? Go for a walk in one of this country's stunning National Parks and you'll be treated to the finest vistas in the world. What's more, you can rest assured you won't be molested by snakes, spiders, wolves or bears when you're squatting behind the bushes.

Fortunately for Kiwis, the only concern for trampers is accidentally grabbing a handful of poison ivy when behind those bushes. Or is it?

What happens to that human waste when you've pulled up your pants, moved on and the rain comes? It might act as a great fertiliser for a few plants, but something much more sinister is also happening and it's contributing to New Zealand becoming the Campylobacter capital of the world.

Campylobacter is a nasty bacterial disease. Most people who become ill with Campylobacter get acute diarrhoea, cramping, abdominal pain, and fever within two to five days after exposure to the organism. In acute cases, chronic diarrhoea can last up to a week with patients becoming so dehydrated they require intravenous fluids.

In New Zealand, 13,800 cases of Campylobacter were reported in 2003 - which works out at around 290 cases per 100,000 people. Compare that to the United States' rate of 15 cases per 100,000 and you can see how high the infection rate is in this country.

The scary thing is, no one seems to know why we have such a high rate of infection. One answer may be that the reporting and data collection in New Zealand is much more thorough than in other countries. In Australia, for instance, which has an infection rate of 125 per 100,000 people, there is very little Campylobacter in places like the Northwest Territories where the hot and dry weather kills the bacteria. But New South Wales used to have the highest notified rate in the country, so high in fact that embarrassed officials decided to take Campylobacter off the notifiable list, making any claims that country has to low infection rates inaccurate.

It's not just Campylobacter that trampers need to be wary of. There's also Giardia, a hardy protozoa that attaches itself to the intestinal tract; Cryptosporidium, another protozoa which is tougher but less violent than Giardia that afflicted at least 902 people in 2003; Salmonella, a bacterium similar to Campylobacter infected 1400 people in 2003 and then there are the viruses, which are not notified but still pose a risk. Norovirus is considered the most common of these and causes stomach upsets similar to the protozoa.

No one knows how or when the likes of Campylobacter and Giardia found their way to New Zealand. Some people blame international visitors, particularly Germans because the bugs were first came to widespread attention in the 1970s, coinciding with a significant increase in the numbers of Germans, particularly backpackers, visiting New Zealand. But there is no evidence to support this view and scientists agree that it is much more likely the bugs have been here for eons, but never identified properly.

"Nothing has been done in New Zealand on identifying when Giardia first came to New Zealand, but in Iceland they have found Giardia in ancient sediment samples," affirms Errol Kwan who is researching Giardia at the Protozoa Research Centre at Massey University and says it is likely to be the same scenario for New Zealand.

"Giardia is anecdotally blamed on German tourists," adds Environmental Science and Research microbiologist Andrew Ball. "That's pure bunkum! It's always been here and it's only now being reported because methods of discovering it have only recently come about.

"There's no reason to expect [Giardia and Campylobacter] to have just appeared - they just weren't recognised. Scientists weren't looking for them in the 1960s. My feeling is that these things have been around ever since we have."

So if we can't blame the Germans, who can we blame? Trampers and other outdoor users? Actually, it's much more likely that people catch Campylobacter in towns and cities from food bought at the local takeaway or restaurant, or from home cooking, because bad food hygiene is considered the major cause of the infection being passed on. The best way to avoid Campylobacter, advises health authorities, is to cook food properly and make sure your hands are thoroughly washed after coming in contact with raw meat, particularly chicken. Poultry is to Campylobacter what mud is to a pig - paradise. Because the bacteria can be found in faeces, it always pays to wash your hands, and many an unhygienic cook may have inadvertently passed on the bacteria after visiting the toilet and coming back to kitchen.

Water courses in the backcountry may be infected with the bug by wild birds and other animals that have it in the intestine and defecate with abandon all around the bush and near, or in, streams and rivers.

In fact, campy - as microbiologists affectionately refer to Campylobacter - is almost everywhere.

A 2001 study looking into the spread of Campylobacter found the bacteria in 75 per cent of shallow ground water and in 60 per cent of New Zealand's river water. However, the accuracy of this study is questionable because only six rivers around New Zealand were monitored.

Andrew Ball goes a step further, however, saying there isn't a safe, natural, drinking supply anywhere in New Zealand - no rivers, streams or springs are free of bugs like Campylobacter. That's his opinion, though, and he tends to err on the side of caution because he works with the bugs daily and has first hand experience of what something like Campylobacter can do - he's had it.

"It was fairly mild, much milder than a lot of people get," he admits. "I was on the toilet for one day, maybe two and I had half a day off work." While his symptoms were relatively mild, this is probably because he ingested a small number of bacteria.

"I am someone who knows what they are doing," he emphasises, "and I still got it. Nobody can escape this. There's a risk and you can reduce the risk by doing the right things.

"I wouldn't drink untreated water anywhere," he adds. "The safest thing is to boil water."

He even says spring water is unsafe, claiming that you never really know where the spring has emerged. Maybe it pops out of the ground a few kilometres away before going back underground. And wherever the water reaches the surface of the Earth, it will pick up bugs. "There's a chance it reaches the surface before the place you get it from and it could pick up some poo," he says pessimistically. But that's all it takes to infect the waterway and pose a risk - albeit small - to human health.

Many trampers would scoff at such a suggestion, having drunk safely from mountain streams for years. One such tramper is Steve Baker. "The only time I've taken a water filter tramping in New Zealand is when I went to the Abel Tasman," he says. "I would probably take one on the Tongariro Crossing and other places that have high visitor numbers, but I don't really think about it."

And Baker is one person who you would expect to think twice about scooping water straight from a stream into his mouth. He caught Giardia, the most dangerous tramping bug there is, on a trip to Kathmandu several years ago.
"I came down with it on the plane home," he says. "I pretty much blacked out and spent the trip vomiting and with diarrhoea. It was a pretty unpleasant 12-hour flight and I don't have any recollection of it apart from the vomiting, the diarrhoea and constantly passing out."

Baker had to be taken off the plane in a wheelchair, but he made a remarkably quick recovery. "I could walk to my connecting flight," he recalls. "The actual illness was short lived." He was lucky; some people suffer from Giardia for 21 days or more.

Others around the country also seem less inclined to treat their water, too.
Marianne Widmer, the operations manager for the Tuatapere Hump Ridge Track says the company advises walkers "that so far Giardia hasn't been discovered [on the track] and we drink the water and they can if they want. We provide rain water for drinking, or creek water, it's their choice."

She adds that she has never had a problem: "I drink it everywhere in Fiordland and have never been sick myself."

Furhana Ahmad from Stewart Island's Ruggedy Range is also lucky in that Giardia hasn't been discovered in her neck of the woods. "On Stewart Island we don't have Giardia and we either take water from running streams or we get it from the huts where the water is taken from the roofs," she says. "We don't do anything regarding filtering or treatment. I guess we are one of the lucky ones."
But there are some operators around the country, in less remote and more easily accessible areas, that take their own water supply on their excursions. One is Simon Dixon from Canoe Safaris which operates on the North Island rivers the Wanganui, Rangitikei and Mohaka.

"On all of our trips we take water in with us and either boil it if we run out or treat it," Dixon says, adding:: "Personally, I would probably treat all my water. The Wanganui comes a long way through farm land so I definitely wouldn't drink that and likewise, the Rangitikei travels through some farm land. We start our Mohaka trip up near the top so that shouldn't be too bad. But we just like to be on the safe side."

Another person who would rather be safe than sorry is Top of the South Tours' Kathy Harrison who takes guided walks in Abel Tasman National Park. She's suffered from Giardia and insists on taking bottled water with her and her clients when in the park. "Abel Tasman is quite bad," she says. "I tell my customers there might be Giardia in the water and I have sterilising tablets in my first aid kit just in case we run out of bottled water."

But Harrison says she wouldn't go as far as some people have and avoid drinking potentially Giardia-infested water at the cost of her life. As an SAR volunteer she has come across instances where people have died from dehydration because they have been too worried about contracting Giardia. "There's actual documented cases," she reiterates.

As unpleasant as contracting Giardia, Cryptosporidium and Campylobacter is, they are unlikely to kill you.

However, a massive outbreak of crypto in Milwaukee, USA, infected 400,000 people in 1993 and killed 100. The bug had found its way into the water supply and most of those that died were AIDS sufferers.

"Crypto is not seen very often," says Ball. "And those that fare worse are those that are already debilitated."

When in the wilderness, it appears the likelihood of getting ill from drinking contaminated water depends on where you are. In isolated Fiordland and Stewart Island, there is less need to filter water. In the busier Central Plateau and Able Tasman areas, people are more inclined to reduce the risk. And how much of a risk you take when you drink from a wilderness stream may never be known.
"The best estimate I can give is that probably one or two per cent of national cases of the notified infectious diseases are from contaminated drinking-water," Ball says. "But these will include water from taps as well as rivers and streams. There is no way of telling what proportion of reported cases are contracted on bushwalks."

If you do get sick on a tramp, there's not much to be done except wait it out - which in the case of campy can be two to five days and for Giardia 21 days or longer. An old bush remedy is to drink flat lemonade - it contains electrolytes as well as water. When you have diarrhoea, you get rid of a lot of water and sodium potassium carbonates. Flat lemonade provides the rehydration and the electrolytes as well.

Fortunately, most bugs don't make themselves known for a day or two, so there's a good chance you'll be off the trail and at home, or on the way home, when the first stomach cramps and round of vomiting hits. In worse case scenarios, antibiotics will be prescribed to help the victim, but these have an unwelcome side effect in that the antibiotics also kill off your stomach's natural bugs which help with digesting food. An early use of antibiotics may also make diagnosis difficult. And unless dehydration becomes a major issue, many doctors favour letting nature take its course so that the bugs are flushed out of the system naturally.
The upshot is you'll suffer from the symptoms of campy or Giardia for longer as there is nothing left in your stomach to fight the myriad of invading organisms that get destroyed naturally every day.

The best way to treat water is to boil it, as this will kill everything in the water. "You don't even need to boil it for 10-minutes," says Ball. "Bring it to 100 degrees and that's enough. Even 70 or 80 degrees is better than nothing."

Boiling water will kill everything - viruses (such as norovirus), bacteria (such as campy) and protozoa (like Giardia and Cryptosporidium). Filtration will work against bacteria and protozoa, but not viruses as these are generally too small to be filtered out. Viruses are less common in the bush, so a filter is generally all you'll need.

If you don't have a filter or the means to make fire, the best bet is to head as far upstream as possible. "The further upstream you go, the less chance there is of stuff getting in there," says Ball. "But," he emphasises, "the safest bet is to treat it."