Hooo-Hooo Hooo-Hooo Vol. 13 Issue 01 - Page 13

• Birds that feed on decomposing carcasses such as raptors and birds that frequent landfill sites. Clinical Symptoms Clinical signs which have been described include progressive weakness and paralysis with loss of ability to fly. Leg paralysis with birds using wings to pull themselves forward. Inability to hold up their heads (limberneck), resulting in drowning. Paralysis of the third eyelid with protrusion across the eye. Most birds dying of botulism are usually in good condition as the botulinum toxin is usually rapidly fatal. • • • • • Diagnosis As they are no characteristic gross or microscopic lesions, diagnosis of avian botulism can be challenging. Suspected diagnosis is usually based on geographic location, time of year, species of avian involved, clinical signs observed and absence of significant pathology at post mortem. The finding of maggots or decomposing carcass material (particularly bone) in the digestive tract of birds suspected of dying from botulism, is also supportive of the diagnosis. Confirmation of the diagnosis relies on the detection of botulism toxin within the intestinal tract of dead birds. The biological mouse protection test has largely been replaced with the botulism toxin ELISA and qPCR for the various botulism toxin genes. Monitoring and surveillance documenting geographic locations, conditions and dates of outbreaks, facilitates the early prediction and recognition of future disease outbreaks. References 1. Rocke, T. E., and J. K. Bollinger. 2007. Avian botu- lism. in N. J. Thomas, D. B. Hunter, and C. T. Atkin- son, editors. Infectious diseases of wild birds. 377- 416 Blackwell Publishing, Ames, Iowa, USA. 2. Son K et al. 2018. Minimizing an outbreak of avian botulism (Clostridium botulinum type C) in Incheon, South Korea. The Journal of Veterinary Medical Science. 80: 553–556. 3. The State of Victoria Department of Environ- ment and Primary Industries Melbourne, Aus- tralia. 2014. Avian Botulism Information kit. 4. Vidal D et al. 2011. Real-time polymerase chain reac- tion for the detection of toxigenic Clostridium botu- linum type C1 in waterbird and sediment samples: comparison with other PCR techniques. Journal of Veterinary Diagnostic Investigation 23: 942-946. 5. Wildlife Health Australia Fact Sheet. Botulism in Australian wild birds. www.wildlifehealthaustralia.com.au. 2019:7. Control in outbreaks. Removal of dead birds and fish is highly effective in removing high protein carcass and maggot sources of toxin. Collection of carcass material with double bagging and incineration is the most effective means of toxin destruction. Burying of carcasses is a less effective control mechanism. Guidelines suggested for handling bird or fish carcasses include: • • Once carcass collection is complete, dispose of gloves in a bag and thoroughly wash hands. For burial of carcasses, ensure this is done away from the shoreline, remove them from the garbage bag(s), and bury them at least 75 cm deep, to discourage other animals from unearthing them. Burning / incineration of Avian Botulism infected carcases is considered the safest method of disposal. Do not compost carcasses of suspected Avian Botulism intoxication. (Courtesy of The State of Victoria Department of Environment and Primary Industries Melbourne, Australia). Wear protective gloves when handling suspected contaminated carcasses. Carcasses should be double bagged. 2019 ISSUE 01 13