The same clade of Clostridium botulinum strains is causing avian botulism in southern and northern Europe

Avian botulism is a paralytic disease caused by Clostridium botulinum-produced botulinum neurotoxins (BoNTs), most commonly of type C/D. It is a serious disease of waterbirds and poultry flocks in many countries in Europe. The objective of this study was to compare the genetic relatedness of avian C.botulinum strains isolated in Spain with strains isolated in Sweden using pulsed-field gel electrophoresis (PFGE). Fifteen strains were isolated from Spanish waterbirds using an immunomagnetic separation technique. Isolates were characterized by PCR, and all were identified as the genospecies Clostridium novyi sensu lato and eight harboured the gene coding for the BoNT type C/D. PFGE analysis of the strains revealed four highly similar pulsotypes, out of which two contained strains from both countries. It also showed that outbreaks in wild and domestic birds can be caused by the same strains. These results support a clonal spreading of the mosaic C.botulinum type C/D through Europe and give relevant information for future epidemiological studies.
This research was supported by/executed in the framework of the EU-project AniBioThreat (Grant Agreement: Home/2009/ISEC/AG/191) with the financial support from the Prevention of and Fight against Crime Programme of the European Union, European Commission – Directorate General Home Affairs. The project was also sponsored by the Spanish Ministry of Environment (Grant OAPN 035/2009). IA was supported by a JAE PRE grant from the Spanish Council of Research (CSIC). The IMS methodology was financed by the Norwegian Agricultural Authority, Animalia, Felleskjøpet fôrutvikling, Fiskå Mølle and Norgesfôr through the Norwegian Research Council (Grant Number 199375/I99).