Type E Botulism Poisonings Linked to Invasive Species
More than 100 dead loons and other migratory birds have washed up on Great Lakes shores in the past week, prompting the New York State Department of Environmental Conservation (DEC) to suspect another botulism-poisoning episode linked to the spread of invasive species.
DEC is investigating the die-off and, although all results are not complete yet, preliminary evidence closely matches die-offs related to Type E botulism that have occurred every year on Lake Erie since 2000 and Lake Ontario since 2002, during fall migration, according to state Wildlife Pathologist Ward Stone.
Those incidents are tied to two invasive species consumed by birds during migration stopovers: the quagga mussel and a fish called the Round Goby. Loons especially feed on the Round Goby. As the Round Gobies have proliferated in recent years, particularly in Eastern Lake Ontario, cases of botulism poisoning have increased, said David Adams, a DEC waterbird specialist.
“Unfortunately, this has become an annual event,’’ Adams said.
Other birds impacted include the Red-breasted Merganser, Ring-billed Gull, Herring Gull, Great Black-backed Gull, Horned Grebe, Long-tailed Duck, Greater Scaup, Double-crested Cormorant and the White-winged Scoter. The single species with the greatest mortality has differed each year.
There have been no reports of any human illnesses associated with these outbreaks, though people should be careful. Type E botulism is a specific strain of botulism most commonly affecting fish-eating birds. It causes paralysis in the affected birds and is often fatal. The disease results from the ingestion of a toxin produced by the botulism bacterium and can be harmful to humans who eat birds or fish that have been poisoned by this toxin. (For more information about Type E botulism, go to http://www.dec.ny.gov/animals/28433.html.)
Botulism-related die-offs first appeared in southern Lake Huron in 1998 and appeared in eastern Lake Erie in 2000. Since the first observed outbreak in New York, DEC has established extensive shoreline surveys of both lakes during fall migration. This allows the Department to not only collect dead birds in certain areas but also to extrapolate about mortality rates due to Type E botulism around the lakes. DEC estimates that approximately 41,000 migratory birds have died on Lake Erie since 2000 and approximately 10,300 on Lake Ontario. Type E botulism impacts on Lake Ontario have been rising rapidly and, in 2006, Lake Ontario surpassed Lake Erie in bird deaths.
The Common Loons found dead on Lake Ontario and Lake Erie are believed to have traveled primarily from Canada. Although a significant number of Common Loons nest on lakes throughout the Adirondack Park, recent studies show these populations do not stopover on Lake Erie or Lake Ontario during migration and, therefore, are not at risk for this botulism event.
Hunters and anglers are advised not to harvest waterfowl or fish that are appear to be sick. Cooking may not destroy the botulism toxin. DEC reminds hunters and anglers to take the following precautions for preparing all fish and waterfowl:
- Harvest only fish and waterfowl that act and look healthy.
- Wear rubber or plastic protective gloves while filleting, field dressing, skinning or butchering birds, fish or wildlife. Remove and discard intestines soon after harvest and avoid direct contact with intestinal contents.
- Wash hands, utensils and work surfaces before and after handling any raw food, including fish and game meat.
- Keep fish and game cool (either with ice or refrigerated below 45 degrees Fahrenheit/7 degrees Celsius) until filleted or butchered, and then refrigerate or freeze.
- Cook fish and other seafood to an internal temperature (in the thickest part) of 140 degrees Fahrenheit (60 degrees Celsius). Cook game birds to an internal temperature of 165 degrees Fahrenheit (74 degrees Celsius).
If you must handle dead or dying birds or fish, use rubber or plastic protective gloves or a plastic bag. Any discovery of dead or distressed fish or wildlife, such as waterbirds showing a condition known as "limberneck" that results from paralysis of the neck muscles, should be reported to DEC's Division of Fish and Wildlife office in Buffalo at (716) 851-7010, Allegany at (716) 372-0645, Avon at (585) 226-2466, Syracuse at (315) 426-7400, Cortland at (607) 753-3095, Watertown at (315) 785-2261 or Cape Vincent at (315) 654-2147.