LAKEPORT, Calif. – County officials are continuing to investigate the case of a dog that was euthanized after it went swimming in Clear Lake and became ill.

The dog fell ill the day after swimming in an area thick with tules and with evidence of a blue-green algal bloom in the Konocti Bay area, according to a county report.

The dog later was euthanized, officials said.

After the dog's veterinarian notified the county of the case, Lake County Public Health and Lake County Water Resources arranged for special testing of clinical and water samples at the California Animal Health and Food Safety Laboratory in Davis, according to the Wednesday report.

County health officials said test results of a single water sample obtained in the Konocti Bay area showed elevated levels of microcystins – toxins associated with certain types of cyanobacteria (blue-green algae).

These unusually elevated results may prove to be transient or highly localized, but Lake County officials said they are aggressively investigating a potential link to the recent severe illness in a dog.

The World Health Organization (WHO) adopts guidelines for risks of health effects from recreational exposure.

The county said the first round of tests conducted show elevated levels which fall within the WHO range for a high risk of adverse health effects.

While the test taken was a pin point sample in a large water body, the health risk associated with these high levels should be taken seriously, the county said.

Repeat testing will be done to confirm the consistency of the single sample result from Konocti Bay. Tests of clinical samples to more directly determine the cause of illness in the dog for algal toxins and amanitin – a type of mushroom toxin – are pending, officials said.

To date, the single elevated measurement is a rare occurrence, according to the county. Additional study and coordination with the scientific community is needed to more clearly define all aspects of risk associated with blue-green algae.

This case of dog illness and the associated elevation of cyanotoxins in a water sample is cause for renewed emphasis on precautions to take, according to health officials.

Measurements of cyanotoxins in Clear Lake over the past several years have been much lower, often so low as to be undetectable. However, officials recognize that there are factors that are not well understood that may prompt higher toxin production under certain circumstances that cannot always be predicted.

If a link between the recent dog death and cyanotoxins is ultimately demonstrated, it would be the first such laboratory documented case in Lake County, the report stated.

Although the continuing investigation has not proven a connection between the dog’s illness and cyanobacteria, local officials are urging the public to be aware of potential risks and take appropriate steps to stay safe. Dogs are more likely than people to ingest water while swimming and may have even greater exposure if retrieving toys that are submerged in affected water.

Those steps include:

• Avoiding contact with water in lakes, ponds and streams where there are visible signs of algal blooms, including surface foam, scum, or a pea soup appearance, particularly in quiet, protected areas where there is little current or wave action.
• If humans or pets make any direct contact with water showing signs of blue-green algae, skin and pets should be washed with fresh water. Pets should not be allowed to lick their coats clean of the algae.
• Never drink untreated lake or other surface water. Boiling water does not guarantee that it is safe to drink.

Public access areas of Clear Lake that show signs of blue-green algal accumulations are posted with health advisories intended to help residents and visitors make informed decisions. Even if an area is not posted, the public is urged to use caution if they can see signs of algal growth.

Lakefront property owners are encouraged to be familiar with health recommendations and to take precautions for themselves and their guests as appropriate.

Assistance with signage is available from Lake County Environmental Health, 707-263-1164.

For more information visit http://www.co.lake.ca.us/Government/Directory/Environmental_Health/Blue-Green_Algae.htm or
http://www.cdph.ca.gov/healthinfo/environhealth/water/pages/bluegreenalgae.aspx .