Human and animal botulism surveillance in France from 2008 to 2019

Abstract

Botulism is a human and animal neurological disease caused by the action of bacterial neurotoxins (botulinum toxins) produced by bacteria from the genus Clostridium. This disease induces flaccid paralysis that can result in respiratory paralysis and heart failure. Due to its serious potential impact on public health, botulism is a closely monitored notifiable disease in France through a case-based passive surveillance system. In humans, this disease is rare, with an average of 10 outbreaks reported each year, mainly due to the consumption of contaminated foods. Type B and to a lesser extend type A are responsible for the majority of cases of foodborne botulism. Each year, an average of 30 outbreaks are recorded on poultry farms, about 20 cases in wild birds and about 10 outbreaks in cattle, involving a large number of animals. Mosaic forms C/D and D/C in birds and cattle, respectively, are the predominant types in animals in France. Types C and D have also been observed to a lesser extent in animals. With the exception of botulinum toxin E, which was exceptionally detected throughout the period in wild birds, the types of botulism found in animal outbreaks are different from those identified in human outbreaks over the last ten years in France and no human botulism outbreaks investigated have been linked to animal botulism. In line with the One Health concept, we present the first integrative approach to the routine surveillance of botulism in humans and animals in France.

Clostridium botulinum type C, D, C/D, and D/C: An update

“…Regarding poultry, outbreaks have been reported in chicken broilers, turkeys, pheasants and to a lesser extent ducks, guinea fowls, laying hens, gooses, and quails (Souillard et al, 2014;Le Maréchal et al, 2016aVentujol et al, 2017). Analysis of the toxin types occurring in France confirmed the predominance of types A and B in human botulism in both foodborne and infantile cases, and exceptionally type F (Mazuet et al, 2017;Rasetti-Escargueil et al, 2020;Le Bouquin et al, 2022). The C/D mosaic form is the predominant BoNT in birds in this country, even if BoNT/D is also observed, and only BoNT/D/C and C have been identified in recent years in cattle.…”

“…A study conducted on human botulism surveillance in France over the last decade shows that the incidence of human botulism has been relatively stable over time with an average of ten outbreaks/year for a total of 100 cases (Le Bouquin et al, 2022). (Rocke, 2006), among which Anatidae appears to be the most affected family in wild birds, at least in France (Ventujol et al, 2017).…”

“…Clinical signs observed in cattle are due to ingestion of BoNTs and/or BoNT-producing clostridia by animals via drinking water (Doutre, 1969) or feeding (pastures (Popoff, 1989), forages (Bano et al, 2015) and on-farm manufactured feeds (Le Maréchal et al, 2019), silage (Myllykoski et al, 2009;Guizelini et al, 2019), or haylage previously contaminated with C. botulinum (Relun et al, 2017). Two major sources of contamination leading to bovine botulism outbreaks have been identified.…”

“…Two major sources of contamination leading to bovine botulism outbreaks have been identified. One is the presence of animal carcasses (domestic or wild) that provide a substrate for the development of C. botulinum and production of BoNT (Le Maréchal et al, 2019). The second one is poultry manure, as poultry can be asymptomatic carriers of C. botulinum (Souillard et al, 2017(Souillard et al, , 2021.…”

“…The source of manure contamination is asymptomatic poultry carrying C. botulinum, and excreting it into the litter (Souillard et al, 2017(Souillard et al, , 2021. Contamination of water or feed by a dead animal is also a major source of contamination for outbreaks of bovine botulism (Galey et al, 2000;Le Maréchal et al, 2019). Regarding commercial feed, drinking water and cattle litter, these vehicles of contamination appear to be less important, due to good management practices that favor their control (discarding of manure and carcasses, storage conditions of feed, cleaning of equipment, no reuse of poultry litter...).…”