Scientists study thousands of dead fish in eastern Lake Ontario

Environmental scientistsaretryingto determine what killed thousands of fish that washed up on Lake Ontario's eastern shore this month.

New York State's Department of Environmental Conservation is trying to determine if a virus discovered this spring in some species, a botulism outbreak or something else may be the problem.

In June, scientists collected large numbers of dead round gobies and some dead muskies in the Thousand Islands area. Testing confirmed a virus known as viral hemorrhagic septicemia, or VHS, in several fish species from Lake Ontario and the St. Lawrence River.

Environmental officials say VHS is relatively common in continental Europe and Japan, and poses no threat to humans.

An outbreak of botulism last year means officials will also test for the bacterium Clostridium botulinum, a nerve toxin that causes the rare but serious paralytic illness. In August, New York officials found several dead birds along the Lake Ontario shore and in the Thousand Islands that tested positive for Type E botulism.

Earlier this month, Environment Canada researchers said they had found a dozen different types of toxic drugs in water samples from the St. Lawrence River in Quebec.

The drugs include non-prescription anti-inflammatories such as ibuprofen, prescription antibiotics and drugs to treat epilepsy and Alzheimer's disease. Researchers even found caffeine.

Although the amounts were minuscule, the study raises many questions about the long-term effects of pharmacological pollution in the country's waterways.