Limber-neck occurs at an advanced stage of botulism poisoning. 



The Botulism Cycle 



Favorable environmental conditions occur in the tissues of decaying animal and insect car- 

 casses. The decomposition process uses up all available oxygen in the carcass, creating 

 anaerobic conditions. Bacterial spores ingested during the life of the animal germinate after 

 death. As the bacteria multiply and die, toxin is released. 



Outbreaks of avian botulism occur when the toxin is taken in by birds. The die-off may 

 begin as birds feed directly on invertebrate carcasses that contain the toxin, or as a result 

 of feeding on live maggots of flesh-flies and blowflies. Flies lay their eggs on dead 

 vertebrates, and the resulting maggots store botulinal toxin in their bodies as they consume 

 the carcass. More than 5,000 maggots can be produced by a single bird carcass; consump- 

 tion of just two to five toxin-bearing maggots is often enough to kill a duck! 



