A Case Report of a Botulism Outbreak in Beef Cattle Due to the Contamination of Wheat by a Roaming Cat Carcass: From the Suspicion to the Management of the Outbreak.

Alain Viry,Olivier Hulin,Caroline Le Maréchal,Marianne Chemaly,Cécile Chuzeville,Christelle Mazuet,Christine Rubbens,Françoise Pozet,Eric Sellal,Sandra Rouxel,Laure Martin,Typhaine Poëzevara,Sabrina Macé

doi:10.3390/ani9121025

Abstract

Simple SummaryThis study presents in detail a botulism outbreak in a beef cattle farm where the source of contamination was identified as a carcass of a roaming cat that had contaminated stored feed and initiated the botulism outbreak. In this case report, we present how the diagnosis was performed by describing the clinical signs and the analyses that were conducted; how the source of contamination was identified by analyzing samples collected on the farm, and finally, how the outbreak was managed so as to prevent recurrence of the disease and persistence of the contamination in the farm.We report a botulism outbreak in Charolais cattle fed with wheat flour contaminated by Clostridium botulinum type C and the management of the outbreak at each step from the clinical suspicion to the cleaning and disinfection operations. Diagnosis was based on typical suggestive clinical signs and detection of C. botulinum type C using real-time PCR in samples collected from three young affected bulls. All young exposed bulls and cows (18 animals) eventually died, but three young bulls and one cow were recovering when it was decided to euthanize them. C. botulinum type C was detected in the liver of these four animals. Analysis of the ration components demonstrated that wheat flour, wheat, and the mill used to make flour were positive for C. botulinum type C. A dead cat positive for C. botulinum type C was discovered in the silo where wheat grain was stored and was considered the source of contamination. The cat’s entire body was found mummified, well preserved, and not rotting in the silo. Specific measures, in particular, vaccination of the rest of the herd and cleaning and disinfection operations, were implemented to prevent any recurrence of the outbreak. The presence of wild animal carcasses in feed harboring anaerobic conditions like silage, in particular during harvesting, are known to be at risk for the initiation of a botulism outbreak. This outbreak is a reminder that the presence of an animal carcass in feed, regardless of the kind of feed and whenever the contamination occurs, either during harvesting or storage, is sufficient to induce a botulism outbreak.

Highlights

Botulism is a severe neuroparalytic disease that affects humans, non-human mammals, birds, and fish
C. botulinum type C was detected in the four animals that were recovering, notably in the liver, even 21 days after the last death reported on the farm and one month after the end of exposure to contaminated feed
C. botulinum type C was not detected, they were in contact with sick animals and contaminated matrices. Such investigations have hardly ever been conducted up to now [39] they are of main importance to evaluate worker’s exposure during outbreaks. This type C botulism outbreak induced the loss of 18 cattle representing 100% mortality among animals fed with contaminated flour

Summary

Introduction

Botulism is a severe neuroparalytic disease that affects humans, non-human mammals, birds, and fish. It is caused by botulinum neurotoxins (BoNTs) produced by BoNT-producing clostridia, in particular, C. botulinum. BoNTs inhibit acetylcholine release in cholinergic nerve endings, resulting in muscle paralysis [1]. Human botulism is associated with BoNT types A, B, E, and F, while animal botulism is mostly associated with BoNT types C, D, C/D, and D/C [3]. Types A, B, C, D, and D/C have been shown to produce disease in cattle [1,4], while type D/C is the most common current BoNT associated with cattle botulism in Europe [3,5]

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