Nodularia

Nodularia spumigena

Other names

blue green algae

Description

Algae are coiled filaments, each consisting of a chain of cells. The coils are up to 1mm long and less than 0.01mm wide. The coils have a knobbly appearance when forming spores. The algae produces gas bubbles. Grossly the water appears green, murky, foamy with accumulations of purplish rotting algae and has a characteristic smell.

Similar plants

Other blue green algae.

Distribution

Thermal regions of lake Rotorua, dune lakes in Northland and West Coast of the North Island, Lakes Forsyth and Ellesmere in Canterbury.

Toxin

Contains an hepatotoxin which has potent effects on the liver with tiny quantities having a lethal effect in hours. Very small quantities over a period of time promote cancers.When washed ashore the algae can rot causing the release of toxins.

Species affected

All species susceptible. Reported cases in cattle, dogs and sheep.

Clinical signs acute

Sudden death.

Clinical signs chronic

Post mortem signs

Diagnosis

History and clinical signs. Some laboratories are able to assay for the toxins, or microscopic examination may reveal the cyanobacteria.

Differential diagnosis

Other hepatotoxic compounds or poisons that cause sudden death e.g. yew, oleander etc.

Treatment

Animals are often found dead or die before treatment can be given.

Prognosis

Poor, lethal effects in hours.

Prevention

Avoid contaminated water.

References

Wood, S. (2001) Cyanobacteria an underestimated risk to animal health in New Zealand? Vetscript, December 2001, pp4 5.

4 October, 2007