May 16, 2008

Guidelines for Handling Birds With Suspected Cases of Botulism Announced

The Department of Natural Resources, in conjunction with the Michigan Departments of Agriculture and Community Health and the Michigan Sea Grant Extension, today announced a series of protocols to provide the public with information on how to handle birds suspected of dying from Type E botulism.

"For the past two years on Lake Michigan, we have had a number of waterfowl and other shore birds die due to Type E botulism," said DNR Wildlife Biologist Tom Cooley. "We now have protocols in place for the public that explain what to do if they find a dead bird washed up on shore. We also will be providing information to waterfowl hunters this year who might be hunting in these areas."

In 2006 in the Upper Peninsula, the die-off occurred in Menominee, Delta and Schoolcraft counties with an estimated mortality of 600 birds. The species involved were double-crested cormorants, ring-billed gulls, horned grebes, common loons, red-breasted mergansers and red-necked grebes. In the Lower Peninsula, the die-off occurred in Leelanau, Mason, Benzie and Grand Traverse counties with an estimated mortality of nearly 3,000 birds. The species involved were grebes, double-crested cormorants, gulls, mergansers and common loons.

In 2007 in the UP, the die-off occurred in Delta, Schoolcraft and Mackinac counties and involved common loons, long-tailed ducks, horned grebes, white-winged scoters, herring gulls and red-necked grebes. In the LP, the die-off occurred in Leelanau, Benzie, Emmet, Charlevoix (including Beaver Island) and Antrim counties. DNR wildlife biologists also hear reports of other counties involved, but received no birds to examine. There were at least 17 species of waterbirds involved with the most common being double-crested cormorants, ringbilled gulls, horned grebes, common loons, common mergansers and long tailed ducks. Two additional species of interest are the Caspian tern and the piping plover, which are state threatened and federally and state endangered, respectively. The estimated mortality for the Sleeping Bear Dunes National Lakeshore, which was highly monitored, was 1,135 birds.

The total mortality for both peninsulas was 7,500 birds, including birds from the Sleeping Bear Dunes. The numbers were much greater in 2007 in the UP than they were in 2006.

The majority of the mortality began in late August and extended into the middle of November. There was a small die-off in June along the Sleeping Bear Dunes area, and that is when the Caspian terns and the piping plovers died. DNR wildlife biologists believe the likely route of transmission of Type E Botulism in Lake Michigan, as well as in Lake Erie and Lake Ontario, probably includes Cladophora algae, zebra and quagga mussels and the round goby.

The algae establish anaerobic conditions in which the botulism bacterium—found in the bottom sediments of the Great Lakes—proliferates. The bacteria, and the toxin it produces, are ingested by the mussels and the mussels are in turn eaten by the gobies.

Birds can become infected either by eating the mussels directly, eating gobies or other fish that may be involved that are sick or dead due to the botulism toxin, or by scavenging carcasses of birds or fish that have died from botulism. Cooley said that property owners along Lake Michigan who come across dead water birds should take precautions, such as making sure pets do not come in contact with wildlife carcasses. It may be necessary to have pets on leashes in areas where fish and bird dieoffs are occurring. Cooley added that no Type E botulism illnesses have been associated with swimming along the lakeshore where fish and bird die-offs have occurred. He cautioned, though, that pets and humans can become sick if they ingest the botulism toxin by eating a contaminated bird or fish.

The protocols issued today by the agencies for Lake Michigan homeowners who may find dead water birds on the beaches include:

• Bird carcasses should not be handled with bare hands. Wear gloves or use a garbage bag over your hand to collect bird carcasses.
• Bird carcasses should be placed in garbage bags. The number of birds per bag will depend on the size of the birds and the quality of the garbage bags.
• Carcasses can be disposed of either by including them with your household trash or by burying them. If you bury carcasses, you need to do so away from the shoreline, remove them from the garbage bag(s) and bury them at least two feet deep. Burying them to this depth will discourage other animals from unearthing them. Do not place them in compost.
• You can bury animal carcasses on your property only, unless you receive permission from the property owners to remove carcasses from their land.
• Once you finish handling the carcasses, you should dispose of your gloves in a garbage bag and place them in trash that is going to a landfill.

The agencies also have established protocols for collection of carcasses for examination. These include:

• Any bird collected for submission for a necropsy or botulism testing must be freshly dead. Presence of a bad smell or maggots is evidence that the bird has been dead longer than 24 hours and is not acceptable for testing. Decomposed carcasses can cause false positive results.
• Submission of birds for examination and testing needs to be limited to two individuals per species per county. Once the disease is confirmed in a species in a county, no additional testing will be needed on that species.
• Individuals handling dead birds should wear rubber, plastic or disposable gloves. Place the carcasses in a garbage bag and seal the bag. Collected specimens need to be bagged individually or by species and a history provided. The history should include date collected, location (county, township, range and section if possible), the numbers and species involved in the die-off and a contact name and address.
• The nearest DNR office should be contacted and arrangements made to deliver the specimens to the office. It may be possible for DNR personnel to pick up specimens, but it may be necessary to deliver them. DNR field personnel will forward the specimens to the DNR Wildlife Disease Lab in Lansing for necropsy and botulism testing.

Guidelines for waterfowl hunters in the northern Lower Peninsula and the eastern Upper Peninsula also were developed. The guidelines will be printed in the 2008 Michigan Waterfowl Guide. They include:

• Birds with Type E botulism may be lethargic, have difficulty holding their head out of the water or be unable to fly.
• Hunters should harvest only waterfowl that act and look healthy.
• Hunters should wear rubber, plastic or disposable gloves while field dressing, skinning or butchering waterfowl.
• Remove and discard intestines soon after harvesting and avoid direct contact with the intestinal contents.
• Wash hands, utensils and work surfaces before and after handling any meat.
• Keep waterfowl cool (either with ice or refrigerated) below 45°F until butchered, then refrigerate or freeze.
• Cook waterfowl to an internal temperature of 165°F. Cooking may not destroy Type E botulism toxin.

More information on Type E botulism and the protocols developed for handling or collecting dead birds is available on the DNR Web site at www.michigan.gov/dnr

The DNR is committed to the conservation, protection, management, use and enjoyment of the state's natural resources for current and future generations.

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Also See: Michigan Sea Grant Avian Botulism

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