Stream water poses health risk

Press, 24 September 1988, Page 18

Stream water poses health risk

PA Palmerston North That popular New Zealand experience — drinking water from a “clear, cool stream” — has become a real health risk, says a Massey University scientist. Dr Tim Brown, of the department of microbiology and genetics, is researching a new waterborne disease called giardiasis He said it was caused by an intestinal parasite, giardia, which upset digestion and caused flatulence, stomach pains, weight loss, nausea and diarrhoea. Giardia produced cysts which were shed in faeces at the rate of millions per bowel motion; 10 cysts could cause an infection, said Dr Brown. The disease was not fatal but could make sufferers extremely weak. In New Zealand, the disease was not confined to trampers, refugees or travellers from abroad, said Dr Brown. Many water sources which supplied small isolated populations were not treated and though the most effective solution was filtering, this was difficult with reasonably large volumes of water.

In the United States trampers used to be able to drink safely from most freshwater sources but now in some parts it was unwise to travel without a portable filter to get giardia cysts out of the water.

“The indications are that New Zealand is going the same way.” Dr Brown said available figures showed giardiasis was already a significant public health problem. Last year 854 cases were reported in Auckland and a Christchurch private health. laboratory identified 244 cases — but they were “only the tip of the iceberg”. Another “frightening” aspect was the discovery, in America and New Zealand, of a significant number of giardia in beavers, dogs and cats. He said giardiasis was not limited to rural districts in New Zealand — it was becoming more common in Auckland, Palmerston North, Hamilton, Wellington and Canterbury. Most urban water supplies were of a high standard but urban dwellers often spent holidays in areas where waste disposal and water supply systems ran side by side and “left much to be desired”. Many New Zealanders lived in “high risk” areas for a considerable time each year, he said. Such areas had small permanent populations which could not afford updated facilities to cope with the excessive seasonal influx of people. Dr Brown said he planned to do further research on the disease with a group of scientists.