Ornis Hungarica. vol.17-18. (2009) p.21-32.
Avian botulism: Hungarian and international aspects
Botulism is a bacterial disease caused by exotoxins produced by the obligate anaerobe Clostridium botulinum. The etiologic agent is a spore-forming bacterium, in which form – carried by the wind or several animals – can be found everywhere and – under favourable environmental conditions – can germinate into vegetative cells and synthesize toxin. The species had been divided into seven types, A to G, based on the serological specificity of the toxins. The disease can affect almost any species of vertebrata – including humans. Botulism in waterfowl is caused mainly by Cα subtype of type C Clostridium botulinum. These strains produce C1 toxin. Physiological effect of the seven toxin types are the same: causing flaccid paralysis by inhibition of acethyl-choline releasing in neuromuscular synapses. Outbreaks affecting ducks and other waterfowl are reported from the 1900’s. In 1959, the first documented avian botulism case in Hungary (“Fehér-tó” nature reserve) was followed by others from the 1960’s. At that time, diseases mainly happened among domestic ducks kept on fish ponds, affecting thousands of birds and causing huge economic losses. Today the biggest problem is the enormous intangible loss derived from the death of protected bird species.