A highly contagious disease is circulating in France. The Institut Pasteur warns against shigellosis which causes severe diarrhea. A disease that is difficult to treat, particularly as the bacteria that cause it are becoming increasingly resistant to antibiotics.
• What is this disease?
Shigellosis, or bacillary dysentery, is an infection of the intestine caused by different Shigella-type bacteria (Shigella dysenteriae, Shigella flexneri, Shigella boydii and Shigella sonnei), also called shigella, explains Inserm.
Specifically, during contamination, shigellae invade the colonic mucosa and cause an inflammatory reaction that leads to the destruction of infected tissues. This causes severe diarrhea for the patient for three to four days.
This disease is extremely contagious: 10 to 100 bacilli are enough to cause an infection. The disease kills about 200,000 people worldwide each year, including 65,000 children under the age of 5.
It is more frequent in tropical regions where shigellosis is endemic throughout the year due to the lack of hygiene and sanitary infrastructure. But in recent years, outbreaks have appeared in developed countries. In France, the National Reference Center for Escherichia coli, Shigella and Salmonella identified more than 1,300 Shigella strains in 2019, detected eight Shigella sonnei and one Shigella flexneri epidemics, according to its annual report.
• What are the symptoms?
Shigellosis begins abruptly after a brief incubation. Among the symptoms: abdominal pain accompanied by vomiting; frequent, numerous or even bloody stools; but also fever and deterioration of the general state, details the Institut Pasteur on a page dedicated to the disease.
Acute complications are especially feared in infants and young children (hypoglycemia, bacteremia or sepsis, dehydration, collapse, acute renal failure, intestinal obstruction or peritonitis, Inserm list).
Chronic complications can also cause prolonged malnutrition with severe growth retardation in height or weight.
• How is it transmitted?
Human beings are the only reservoir of this bacterium. Since a patient can shed bacilli in his stool for weeks after a dysenteric episode, the risks of contagion are significant.
Specifically, shigellosis is spread by the fecal-oral route, particularly through water, contaminated food, or even flies. In developing countries, the disease mainly affects children but also soldiers on operations, humanitarian workers and tourists.
In industrialized countries, small outbreaks can occur in congregate settings with young children. But in recent years, two of these bacteria (Shigella sonnei and Shigella flexneri) have become epidemic within the male gay community. The Institut Pasteur even speaks of a “new sexually transmitted infection” and calls for more prevention.
“The analysis of the bacterial genome sequences and the characteristics of the cases, which occurred preferentially in adult males, suggest that these strains, native to South Asia, are spreading in particular among men who have sex with men,” explains the Pasteur Institute.
• Why are researchers concerned?
Unlike gastroenteritis, “shigellosis cannot be treated with rehydration alone,” warns the Institut Pasteur. In principle, antibiotics allow a rapid recovery without sequelae. But for several years, multi-resistant strains have emerged, notably of Shigella sonnei and Shigella flexneri. This considerably complicates the recovery of patients.
And the French population is not spared. A study published at the end of January in the journal type of communications He thus spoke out against the “rapid” appearance in France of this “ultra-drug resistant” disease. In fact, these highly antibiotic-resistant strains were first identified in France in 2015. They increased significantly until reaching a peak in 2021 with almost a fifth of the cases.
These strains belong to the same lineage, Shigella sonnei, which became resistant to a key antibiotic some fifteen years ago in South Asia. The bacteria then developed this resistance to other antibiotics.
“It is entirely justified, given the knowledge of previous epidemics, to expect new epidemics of shigellosis in the coming years with these highly antibiotic-resistant strains,” the researchers warn.
For the most severe cases, the only effective antibiotics are carbapenems or colistin “which must be administered intravenously, which makes treatment more aggressive and with more complex follow-up in a hospital setting.”
• Is there a vaccine?
Several laboratories are working on the development of a vaccine. Clinical trials are underway and the first results look encouraging. The Institut Pasteur has also developed a rapid diagnostic test by simple contact with a stool sample.
Scientists also wonder about the different clinical forms of this infection and wonder if the asymptomatic forms would not allow a greater dissemination of the bacteria.
Its “high epidemic potential”, “the appearance of resistance to antibiotics” and “morbidity linked to long-term consequences due to recurrent infections” constitute, according to the Institut Pasteur, “a major public health problem”. The Shigella bacterium is also part of the WHO list of twelve priority pathogens for the search for new antibiotics.
Source: BFM TV
