The first case of a major avian type C botulism outbreak in Poland.

Major outbreaks of avian type C botulism have been rarely reported from Central Europe. In this paper, we report the first severe outbreak of avian type C botulism in Poland. In 2011-12, two epizootics caused by Clostridium botulinum took place at Jeziorsko dam reservoir and affected an estimated number of 5500 birds in 2011 and 1600 birds in 2012. In total, 24 species ofwaterbirds were affected, including mainly waterfowl (37.0%), shorebirds (27.0%), rallids (25.7%), and larids (9.1%). Mallards (Anas platyrhynchos) and coots (Fulica atra) were most commonly represented among all affected species (27.5% and 25.0% of all recorded carcasses, respectively). Laboratory analyses confirmed the presence of type C botulinum toxin in the internal organs of paralyzed birds. This case study from the Jeziorsko dam reservoir demonstrates that this type of shallow-water habitat is especially prone to avian botulism outbreaks in the climatic conditions of Central Europe.