Blue-green algae in the Gippsland Lakes - 16 December 2011
Information for health professionals
Elevated concentrations of the blue-green algal (cyanobacterial) species Nodularia spumigena have recently been found in areas of the Gippsland Lakes. Direct contact with water affected by the blue green-algae bloom can cause irritant effects. Ingestion of affected seafood by humans can adversely affect liver function and is possibly carcinogenic. Health professionals should be alert for symptoms including skin irritation, respiratory effects and hay-fever like symptoms from direct contact. Ingestion may lead to non-specific symptoms related to liver function such as fatigue, abdominal pain or jaundice. Diagnosis is by exclusion, so careful history taking is essential.
Concentrations of Nodularia spumigena in affected areas of the Gippsland Lakes currently exceed human health safety levels.
Nodularin toxin can bioaccumulate in aquatic organisms such as shellfish, prawns and fish. Many aquatic organisms accumulate toxins and transfer them along the food chain. Recent test results have shown that the levels of toxin in seafood (fish/prawns/mussels) collected is above health guideline levels and considered unsafe for human consumption.
Testing has confirmed that the Nodularia spumigena species present in the Gippsland Lakes is producing the toxin, nodularin, which acts as a hepatotoxin.
Toxicity is presumed to be similar to the blue-green algae toxins microcystins that are possibly carcinogenic to humans.
No routine pathology testing for toxin is available in humans. Diagnosis is by exclusion. Careful history taking is recommended.
Associated symptoms from ingestion are likely to be non-specific and related to liver function such as fatigue, abdominal pain or jaundice. Liver function tests are recommended.
If direct skin contact with water affected by the algal bloom has just occurred, people are advised to remove any affected clothing and wash themselves thoroughly with clean water after coming ashore. Clothing and wetsuits should be thoroughly rinsed before being worn again to remove any traces of algae.
Stopping exposure from ingestion of affected seafood is the initial intervention.
Hepatoxins from ingestion of affected seafood can cause abnormal liver function tests that may require clinical management.
As with other blue-green algae toxins like microcystins, it would be expected that long term toxicity would be related to chronic exposure to the toxin.
Visitors and residents are being advised that contact with the water from affected areas of the Gippsland Lakes should be avoided and seafood obtained from affected areas should not be consumed. Water from affected areas of the Gippsland Lakes should not be used for cooking, drinking, washing, showering, stock watering or for pets. Boiling the affected water will not make it safe to use.
Signs have been erected at key recreational access sites around the Gippsland Lakes to advise the public not to come into contact with affected water or consume seafood (fish/mussels/prawns). Media releases have also been issued.
Water users who experience any health effects following recreational exposure or ingestion of affected seafood from the Gippsland Lakes are being directed to seek medical advice.
For current information on affected areas of the Gippsland Lakes please refer to the Department of Sustainability and Environment (DSE) website: www.water.vic.gov.au
For further information on health issues relating to blue-green algae, contact the Victorian Department of Health on 1300 761 874.
Information updates about the cyanobacterial bloom in the Gippsland Lakes is available on the DSE website www.water.vic.gov.au and from DSE's Customer Service Centre on telephone 136 186.
NHMRC, 2008, Guidelines for Managing Risks in Recreational Water. National Health and Medical Research Council.
Water Quality Research Australia, 2010, Management Strategies for Cyanobacteria (blue-green algae): A Guide for Water Utilities.
Victorian Government health information on blue-green algae: http://www.health.vic.gov.au/environment/water/