Outbreak of type C botulism in laying hens

BOTULISM, also known as ‘limberneck’ in poultry, is an intoxication caused by the exotoxin of Clostridium botulinum (Dohms 2008). There are seven antigenically distinct toxin types: A, B, C, D, E, F and G (Radostits and others 2007). Farm animal disease is produced primarily by types B, C and D (Radostits and others 2007). The majority of avian cases are due to type C toxin (Dohms 2008). The toxin binds to peripheral cholinergic nerves and blocks the release of the neurotransmitter acetylcholine. Worldwide, reports of botulism in laying hens are very rare, with only a few outbreaks reported in the literature (Fossum and others 2009). The disease, which is more often observed in broilers (Dohms 2008), has been attributed to the ingestion of preformed toxin in carcases or to toxicoinfection (Blandford and Roberts 1970, Roberts and others 1973, Harrigan 1980, Dohms 1987). Mouse bioassay remains the ‘gold standard’ for the confirmatory diagnosis of botulism (Centers for Disease Control and Prevention 1998). This short communication describes an outbreak of type C botulism in laying hens. The outbreak occurred in a group of 7500 Lohmann layer hens housed at a stocking density of nine birds/m2 in a slatted barn. The birds had been vaccinated at their rearing site against Marek's disease, Gumboro disease, Newcastle disease, …