title: Investigations into an Outbreak of Botulism Caused by Clostridium botulinum Type C/D in Laying Hens.
abstract: This case report describes a recent botulism outbreak in commercial laying hens with a history of increased mortality and flaccid paralysis. Routine diagnostic gross examination and microscopy from seven hens were inconclusive, but botulinum neurotoxin (BoNT) in peripheral blood was neutralized with both type C and type D antitoxins in the mouse bioassay. During a farm visit, 10 additional hens from a 34-wk-old flock on the farm were selected for clinical examination and further sampling. Nine hens were observed in sternal recumbency, with flaccid paralysis of the neck, drooping wings and tail, inability to escape, and bilateral ptosis, and one hen showed nonspecific clinical signs. Samples from cecum and liver were collected, and the gene coding for BoNT was detected by PCR in all 10 cecal samples and in four of the liver samples. Clostridium botulinum mosaic type C/D was isolated from 5 out of 10 hens from either cecum or liver, and the isolates were subjected to pulsed-field gel electrophoresis subtyping. All five isolates produced the same banding pattern, which was identical or showed >90% similarity to isolates from three different outbreaks on broiler farms in Sweden and Denmark during the 2007-10 period. However, they were clearly distinguishable from the predominantly reported pulsotype associated with avian botulism outbreaks in Europe. The authors are unaware of any previous report of C. botulinum mosaic type C/D isolates from laying hens.
authors.affiliation: A Department of Bacteriology, National Veterinary Institute (SVA), SE-751 89 Uppsala, Sweden.|B Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences (SLU), SE-750 07 Uppsala, Sweden.
authors.forename: Hanna
authors.initials: H
authors.lastname: Skarin
authors.affiliation: C Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute (SVA), SE-75189 Uppsala, Sweden.
authors.forename: Ylva
authors.initials: Y
authors.lastname: Lindgren
authors.affiliation: C Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute (SVA), SE-75189 Uppsala, Sweden.
authors.forename: Désirée S
authors.initials: DS
authors.lastname: Jansson
mesh_terms: D000818:Animals; D001681:Biological Assay; D001906:Botulism / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D002645:Chickens; D003014:Clostridium botulinum / Q000145:classification*; D005260:Female; D051379:Mice; D011201:Poultry Diseases / Q000382:microbiology* / Q000473:pathology; D013548:Sweden / Q000453:epidemiology
keywords: Clostridium botulinum; PFGE; botulinum neurotoxin type C/D; botulism; laying hens; poultry