The Michigan Department of Natural Resources recently diagnosed type C botulism in wild waterfowl along the East Arm of Grand Traverse Bay in Grand Traverse County and along Marsh Creek in Woodhaven in Wayne County. During the first week of July, dead mallards were collected and sent for testing at the DNR Wildlife Disease Lab (WDL) in Lansing, and just recently the lab confirmed the disease.
“As of July 7, approximately 20 mallards from Grand Traverse County and approximately 50 mallards from Wayne County have been found dead from type C botulism,” said acting DNR WDL pathologist Julie Melotti. “We will continue to monitor these locations as well as additional sites, for dead birds.”
Botulism is a condition brought on by ingesting a naturally occurring toxin produced by Clostridium bacteria found in the bottom sediments of water bodies. Outbreaks of botulism can occur during periods of hot weather when water temperatures become elevated and water levels decrease.
In the East Grand Traverse Bay area, high water levels in Lake Michigan have spilled over onto the mudflats, creating small pools of water where the toxin is being picked up by waterfowl. Dabbling ducks or other shore birds feeding in the sediment are susceptible to type C botulism.
In Wayne County, Marsh Creek has shallow, warm, and stagnant water due to the lack of rain fall and warm weather. The shallow water depth creates anaerobic conditions necessary for the bacteria to grow.
“This isn’t rare,” said Melotti. “Fortunately, type C botulism is not an immediate risk to humans, although pets, including dogs, could acquire the toxin if they were to eat a dead bird. So at this time, it’s best to keep your dog on a leash.”
In the Great Lakes region, both types C and E botulism are reported annually, although these are the first cases of botulism in Michigan this year. It was first identified in 1936 in ducks on Lake Michigan's Green Bay, and outbreaks have continued to occur in ducks and shorebirds whenever conditions are favorable, with many reports of the disease along both coasts of the Lower Peninsula and on many inland lakes. Typically, type E occurs in fish-eating birds in the open waters of the Great Lakes, while type C occurs in dabbling ducks in shallow water.
How you can help:
“It’s important for us to stop the cycle of botulism once it starts,” said Melotti. “Any dead birds that are on the shoreline need to be picked up and disposed of properly. We don’t want other animals feeding on the carcasses.”
When handling dead wildlife, the use of rubber gloves is recommended. Dead birds can be disposed of in normal garbage pickup destined for a landfill or buried deeply enough that they can’t be easily dug up.
Any dead or dying birds that are found along the south shore of Grand Traverse Bay should be reported to the Traverse City DNR office at 231-922-5280.
Any dead or dying birds that are found in Wayne County should be reported to the Pointe Mouillee State Game Area headquarters at 734-379-9692.
Please provide information on the location, type and number of birds.
In addition, do not place food out for waterfowl or other birds in these regions. Congregating birds in areas where botulism has been found may cause more birds to pick up the bacteria and become sick.