Botulism caused by neurotoxins of Clostridium (C.) botulinum is a rare, but serious lifethreatening
disease in humans and animals. Botulism in livestock is usually caused by the
oral uptake of C. botulinum neurotoxins (BoNT) via contaminated feed and is characterized
by flaccid paralysis. In the recent past a new syndrome caused by BoNT in dairy cattle was
postulated. It was supposed that C. botulinum is able to colonize the lower intestine and
may subsequently produce neurotoxin. The continuous resorption of small amounts of
these BoNT may then provoke the so called syndrome of ‘‘chronic’’ or ‘‘visceral’’ botulism
involving unspecific clinical symptoms, reduced performance of dairy cows and massive
animal losses in the affected herd. To test this hypothesis a case-control study was
conducted involving 92 affected farms and 47 control farms located in Northern Germany.
Fecal samples of 1388 animals were investigated for the presence of BoNT to verify the key
requirement of the hypothesis of chronic botulism. BoNT was not detected in any of the
fecal samples using the most sensitive standard method for BoNT detection, the mouse
bioassay. Therefore, the existence of ‘‘chronic’’ or ‘‘visceral’’ botulism could not be proven.
2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC