Do the waterfowl living around the lake look unhealthy? Does it appear that they have a limp neck which droops to one side? Are they trying to fly but can’t? Are they trying to move their wings, but can’t? These are a few signs that waterfowl have Avian Botulism or what is commonly referred to as Limberneck Disease.
Avian Botulism is a paralytic, usually fatal disease of wild and domestic birds resulting from the ingestion of a toxin produced by the bacterium Clostridium. Although there are several toxins produced by this type of bacteria, only two, Types C and E cause avian mortality. Type C toxin is the most common and can be a recurring issue known to affect all waterfowl, including ducks, geese and swans. Pelicans, gulls, shorebirds, raptors, and upland birds are also susceptible, and places these Florida birds at high risk.
Outbreaks of avian botulism can occur anywhere in Florida’s aquatic environments and this bacterium is common in wetlands and pond and lake shorelines. The bacterium spore is resistant to heat and drying and in some instances the spores have been known to remain viable for years. The “disease environment” this bacterium prefers is typical of Florida’s warm water lakes and canals especially during the hot months from May through October.
Important environmental factors that contribute to Avian Botulism outbreaks include:
Once the botulism toxin is produced, dead birds decompose and their carcasses become hosts for maggots that ingest and accumulate the botulism toxin produced in the carcasses. New birds arriving to the area feed on the toxic maggots and in turn are affected with the toxin and die thereby renewing the botulism death cycle. Fish can also ingest the maggots and endanger common Florida fish-eating birds such as cormorants, anhingas, ospreys and pelicans.
The most effective method of stopping these devastating avian botulism outbreaks is the rapid removal of all animal carcasses. A thorough survey of the waterbody by an experienced lake management crew with the proper tools and equipment is necessary to locate, remove and dispose of carcasses responsibly both initially when the disease first starts and continuously until the outbreak ends.