Diagnosis and implications of botulism

Abstract

BOTULISM is a neuroparalytic condition affecting birds, mammals and fish, and is caused by exposure to toxins produced by various biotypes of Clostridium botulinum. Until a few years ago, botulism was considered to be a rare disease in farm animals in the UK. However, since 2003, there has been an upsurge in the number of suspected cases reported, particularly in cattle and more recently sheep. The diagnosis of botulism is problematic and relies heavily on clinical signs. Confidence in the diagnosis is improved by identifying the risk factors and suspect sources, and by ruling out the more common differential diagnoses. This article describes the clinical signs of classic and atypical disease, and discusses the implications of a diagnosis of botulism with regard to animal welfare, food safety and public health.

Management of Animal Botulism Outbreaks: From Clinical Suspicion to Practical Countermeasures to Prevent or Minimize Outbreaks

“…For toxicoinfectious forms, the incubation period is usually longer, and an indicative period of 4 to 14 days has been reported in the literature. 3,22,40 Signs of the intoxication include reluctance of the animals to rise; the lying posture may be abnormal, and, on rising, the gait may be stilted and the hind limbs splayed and ataxic. Weakness then progresses to the forequarters, head, and neck.…”

“…Birds may also appear lateral or ventral recumbent and comatose or dead. 3,40,41 Recumbent birds intermittently stand and walk a few steps. Often they cannot stand up completely and even walk on their tarsometatarsi.…”

“…More severely affected water birds are unable to walk and drag themselves forward using their wings and beak. 5,40,41 Broilers generally appear ruffled and often show defeathered areas on the back. Affected chickens may have soiled vents caused by diarrhea.…”

“…34 Atypical clinical presentation can appear in cattle because of the ingestion of BoNT/B, including diarrhea, profuse salivation, regurgitation, and vomiting. 40 …”

The Workshop on Animal Botulism in Europe

“…If recommended practices were followed, the spread of spores from chickens could be prevented. 13 What is less well known is how frequently other farm and wild animals act as carriers of spores of C. botulinum. This should be further explored as it could be another risk factor for botulism outbreaks.…”