Fish & Game Keeping A Close Eye On Potential Of Avian Botulism Outbreak

ROBERTS - Soaring temperatures are a sure sign we've entered the dog days of summer, but they are also sign that wildlife managers need to keep a close eye on waterfowl for outbreaks of avian botulism. At Market Lake Wildlife Management Area (WMA), Regional Habitat Manager John O'Neill has been collecting samples of dead ducks, gulls and other birds and sending them off to the National Wildlife Health Lab in Madison, Wisconsin. Lab reports so far have been inconclusive, but O'Neill has observed ducks exhibiting some of the classic symptoms such as "limberneck". The last major outbreaks of avian botulism at Market Lake WMA occurred back in 1996 &1991. Current high temperatures that have plagued the Upper Snake River Region have not only made things uncomfortable for humans, but could be triggering the growth of avian botulism toxin spores that have laid dormant at Market Lake Wildlife WMA. Avian botulism is a disease that is found throughout the world. Its spores can be found in virtually any aquatic environment where waterfowl are present. In order for the spores to mature certain environmental conditions must be met. Water temperature is the critical piece of the puzzle. Additional variables include decaying organic matter such as plants and invertebrates. According to O'Neill, "The cool nights have help to keep the water temperature in the safe range." In order to help manage against avian botulism at Market Lake WMA, dikes were constructed to help break the marsh into smaller cells that can be more easily managed. Controlled burns are also done in portions of the marsh to help reduce the buildup of dead marsh grasses. Avian botulism is not new to wetland areas and IDFG biologists maintain a constant vigil to be sure conditions at areas managed by the Department remain as close to natural conditions as possible. While flooding marshes is a tool that helps to drop water temperatures, current water conditions severely limit this as a realistic option. Ducks are susceptible to type C botulism, which is different than the type that affects humans. Canadian geese are not susceptible to avian botulism. Gulls and loons are mainly susceptible to type E. It is important for the public to note that avian botulism occurs when birds ingest the maggots that thrive on the decaying carcasses. These maggots possess a high concentration of the toxin and only two or three are needed to kill a duck. Avian Botulism is not classified as an "infectious" disease and cannot be spread to humans. Proper cooking will destroy any of the botulism toxins present in waterfowl harvested during the hunting season for human consumption. Staff have been working regularly to pick up deceased birds because of the potential threat they pose if maggots hatch on the carcasses. No avian botulism outbreaks have been reported yet elsewhere in the vicinity.