Mystery or chance? Between 2007 and 2022, five residents of two streets in a village in the Somme contracted Charcot disease. A situation which echoes the excessive mortality of a village in Savoie, Montchavin, observed in 2009. Enigma finally resolved in 2021 after ten years of investigation.
In the medical world, the concentration of a pathology is called a cluster – epidemic focus in French – even if Charcot disease, also called amyotrophic lateral sclerosis (ALS) is not an epidemic. It is, in fact, a neurological disease which causes progressive paralysis of the muscles and generally causes death within less than three years.
“It’s the law of probability”
This cluster, in any case, has been talked about a lot since The Picard Courier relayed the concern of the mayor of the commune of Saint-Vaast-en-Chaussée, a village of less than 500 inhabitants, located near Amiens. After the death of these five people, Public Health France was contacted by the Hauts-de-France Regional Health Agency (ARS) to “determine whether there actually exists a statistical excess of diseases in the population observed”.
If this excess exists, it will then be a question of “determining whether there are one or more local causes for this grouping of cases, other than chance, on which it is possible to act”, indicated, at the ‘AFP, Public Health France. Other “unusual” situations of grouped cases of ALS “have been reported to Public Health France over the last ten years, without it being possible at this stage to hypothesize a common cause for the different cases”, according to Public Health France.
For Pierre-François Pradat, neurologist at the Pitié-Salpêtrière hospital (APHP) and co-president of the scientific council of the Association for Research on ALS (ARSLA), “the cluster phenomenon is all there is to it. is more normal.” “It’s the law of probability,” he explains to 20 minutes. If you throw a handful of matches on the ground, some may end up in a small pile. »
Beware of false morels
“The concentration in this village is not statistically significant,” adds Pierre-François Pradat, who nevertheless specifies that the causes of this rare disease (around 8,000 new cases per year in France) are still very poorly known. “We know that 10% of cases are linked to genes that are now well identified, but research continues into possible environmental and behavioral factors. »
In 2018, suspicions in particular of doping arose after the announcement in Italy of the death of several former football players, suffering from Charcot’s disease. But no hypothesis could be demonstrated on the real causes of this excess incidence of the pathology. On the other hand, certain studies have indeed proven that external factors could become triggers.
“ In the island of Guam, for example, cases of ALS were linked to cyanobacteria,” says Professor Gwendal Le Masson, neurologist and head of the ALS center at Bordeaux University Hospital. And also reporting the study carried out around twelve cases of Charcot’s disease in twenty years, in a village in Savoie: “We discovered that the culprit was the consumption of a false morel, a toxic mushroom. Here too, a cyanobacteria was involved. »
For the Bordeaux professor, “the presence in the water of BMAA cyanotoxin is an avenue to consider” in the case of the Picardy village. “Scientific studies show that pesticides, which are no longer used today, played a role in the appearance of this disease,” continues Gwendal Le Masson. Perhaps we will then have to wait another ten years to have a definitive answer in Saint-Vaast-en-Chaussée?