First presenting with nausea and vomiting, the bacteria produces a toxin which attacks the nervous system evoking weakness starting at the top of the body, which then descends to paralyse the limbs and the respiratory muscles. It is at this stage that medical intervention is particularly crucial if the patient is to survive, as the artificial ventilation provided in the intensive care unit takes over the mechanical operation of breathing.
Most cases of botulism are produced by the organism Clostridium botulinum, in this instance, however, the bacteria responsible was Clostridium baratii – seen occasionally in the USA, but never before in France. In fact only recently has an antitoxin been developed for this rarer form of disease.
Some of the food eaten at the meal shared by the two patients was still available for analysis, but no culprit was found. The usual foods laced with botulinum toxin are canned foodstuffs, such as tuna, or home made meat preparations such as liver pate, dried meat or raw-dried game. As no causative agent was discovered in the French meal, suspicion has now turned to commercially produced items that were consumed, although there is no evidence of this at present.
To avoid botulism, food made at home should be carefully prepared and cans containing foul smelling items should be discarded. In France, practices to avoid botulism have been developed for many decades.
In the south of France, for example, their highly prized truffles are often found in earth rich in clostridial spores. As they are often preserved to ensure a year-round supply, the preserving process must be able to kill the potentially deadly spores. One such process is the local practice of canning the truffles, which is accomplished somewhat informally at the local quincaillerie. An important first step, however, is the sterilization of the truffles that kills the clostridial spores – even though several authorities claim that following the process, the truffles’ potency is reduced. Other methods of preservation include the production of truffle oil, but even truffle oil should be refrigerated to stop the spores from reproducing. (Incidentally herb and garlic oil should be similarly cooled). In fact some assert that the only certain way to kill the hardy clostridium spore is by pressure-cooking food at 120 degrees for 30 minutes: something that is seldom possible if food is to remain edible, of course.
Whatever the source of the first French outbreak of botulism F, the severe neurologic disease produced in the two patients has been treated effectively: both patients have now been allowed home. After extensive artificial ventilation, which in one individual lasted 46 days, significant improvement resulted, although some weakness was still reported on discharge.
Dr Simon Worrell BSc MBBS MRCP, Head of Medical Communications, Healix International.