Update 2.45pm: NEW test results of a Lennox Head lake have been revealed after more than 20 kids fell ill after swimming at the water hole.
Results posted by Ballina Shire Council this afternoon reveal blue-green algae levels at Lake Ainsworth are at green level, the lowest on the council's rating.
The green level means there are no restrictions on recreational use at the lake after the testing was conducted yesterday.
Water samples of the lake are collected weekly to monitor levels of cyanobacteria as well as other microbiological testing for other harmful bacteria.
Microbiological test results were expected to be reported to the council by Friday.
Original story: A LENNOX Head doctor has moved to quell fears of a blue-green algae outbreak at a popular lake after more than 20 children fell ill after swimming over the weekend.
Daniel Ewald, who works part time at the Lennox Head Medical Centre, said it was feasible swimmers may become sick after swimming at Lake Ainsworth.
But he also said there were "plenty of other plausible ways people could get gastroenteritis on a hot day on the lake".
Touching food with dirty hands or leaving food out in the sun were among other main causes of sickness, Dr Ewald said.
However, he did say it was important to speak with family and friends who were at the lake on the same day to determine whether they fell ill or not.
Dr Ewald said it was important to establish "shared factors" to help pinpoint how the illness came about.
If a number of people within the same group were suffering symptoms of gastro, Dr Ewald recommended consulting a GP, getting stool testing and notifying the Public Health Unit.
Regular water testing of the lake would be "very telling" in determining what caused the reported "clusters of gastroenteritis".
Ballina Shire Council has continued to work closely with NSW Health to confirm if the lake water was the cause of a gastro outbreak of water users at the weekend.
Acting manager of environmental health, Kerri Watts confirmed microbiological testing was also conducted yesterday to test the water quality at the lake.
Beachwatch Partnership Program with the Office of Environment and Heritage (OEH) monitors and reports on recreational water quality from November through February at six different swimming areas around the Ballina Shire.
Ms Watts said the results should be reported back to the council by Friday.
Results from blue-green algae testing Monday and Tuesday will be posted on the council's website as soon as possible.
Since Saturday, Ms Watts confirmed six concerned water users have contacted council about sickness from Lake Ainsworth.
Did you come down with gastro? Read on
Dr Ewald offered "rule of thumb advice" for those who were struck down with gastro-like symptoms.
He said the key thing was to stay hydrated to allow the body to regain lost fluid lost from vomiting and diarrhoea.
Water combined with a dash of lemonade or cordial can be just used along with Powerade or Hydrolite drinks.
Monitoring urine was another key sign of monitoring the severity of gastro.
He said urine that's is light in colour and scentless was an indication of good hydration whereas if urine is a dark colour and smelly is a major sign of dehydration.
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