In mid to early October 2009 a few Sacred Ibis were found dead associated with a wetland and breeding colony in Victoria. Later in October a Sacred Ibis was observed to have difficulty standing, and another to be weak in its legs, wings and head. These are typical clinical signs of Botulism. This site has a history of botulism in the past, approximately 5 years ago, 2004?
Botulism toxin acts on nerves that control skeletal muscles and can cause death. Water birds can drown when they cannot lift their heads out of water.
Birds with a low dose of toxin can recover.
Botulism tends to occur in wetlands and along waterways, in drought years, and associated with drying and dropping water levels.
Botulism is caused by the toxin from the bacteria Clostridium botulinum. Bacterial spores persist in the environment.
Carcasses left in the environment are a source of nutrients that support bacterial growth. (When the bacterium is cultured in the lab a meat broth is used.)
The bacteria can persist in the environment from year to year, so botulism outbreaks tend to reoccur and removing carcasses will result in less environmental contamination and reduce potential spread of the disease.
Mammals (including people) and birds are susceptible to the toxin. Disease and death is commonly reported in waterfowl (ducks and swans).
It is possible for a cut to be contaminated, so gloves and protective clothing (boots and covering that can be disinfected, or disposables) should be used when collecting carcasses and in contaminated environments.
Carcasses should be disposed of where they can not be scavenged and moved by other species. The disposal site could be contaminated for many years.
We are interested in reports of possible/suspect botulism to determine the areas and species affected in Victoria during the 2009-10 season. Faculty of Veterinary Science, The University of Melbourne. Email Mobile 0400 119 301