Investigation of a Clostridium botulinum mass poisoning and lessons learned, Ivory Coast, 2023

Abstract

Botulism is a severe neuroparalytic disease caused by neurotoxins produced by certain members of the anaerobic Gram-positive spore-forming bacteria Clostridium. Less documentation is available regarding botulism outbreaks in natural environments within subtropical and tropical climate zones. In the village of Kpo-Kahankro, in the Bouaké-sud district of Côte d’Ivoire, an unusual phenomenon caused 22 deaths. The phenomenon occurred in two separate episodes, the first in December 2022 and the second in January 2023. Epidemiological investigations were carried out to identify the source and stop the phenomenon. The unusual circumstances and the management of this rare epidemic phenomenon merit the sharing of experiences. The aim of our approach was to contain the phenomenon by taking preventive measures. The investigation consisted of questioning patients and their relatives about the circumstances in which the phenomenon occurred. We then counted the cases on the basis of the signs presented by the first patients. An investigation form was used for this purpose. In addition, after data analysis, the suspected sources were collected and sampled for biological and toxicological investigation. These sources were sampled in a clean jar and then sent to the National Public Health Laboratory (LNSP) and the Pasteur Institute of Côte d’Ivoire for toxicological and microbiological tests. The two episodes involved 78 cases, 22 of which died, giving a case-fatality ratio of 28.2%. Symptoms were characterized by vomiting (59.0%), diarrhea (30.8%) and abdominal pain (30.8%). For both episodes, 20 cases out of 44 (45.5%) lived on the same islet where the fetish was installed. Toxicological analyses conducted on the liquid within the fetish yielded negative results, whereas microbiological assessments identified the presence of Clostridium botulinum. The destruction of the fetish and the disinfection of its location on January 23, 2023, followed by the disinfection utilizing chlorinated water applied to all residential and public areas within the village, resulted in the absence of any newly recorded cases. The management of this atypical phenomenon in Kpokahankro highlights the need to follow only the results of epidemiological investigation when investigating the causes of a public health event and making decisions.

Keywords: Bouaké,Epidemiology,Côted'Ivoire.investigation,Clostridium botuilinum