Scarlet fever, a sometimes fatal childhood infectious disease, is making a comeback. They believe that the bacteria responsible for this disease has mutated and adapts better to humans.
- Health authorities have observed regional outbreaks of scarlet fever over the past decade. This childhood disease, sometimes fatal, had strongly regressed in the 1940s.
- Australian researchers assure that this resurgence is not anecdotal and that the disease has mutated, becoming more contagious.
- Scarlet fever is curable. It is manifested by fever, sore throat and rash.
Scarlet fever is a childhood disease that was thought to be relegated to the depths of history, yet Australian researchers are sounding the alarm following the multiplication of cases around the world in recent years. According to these scientists, this is due to a new bacterial mutation of the disease. In their study published this October 6 in Nature, analyzes of scarlet fever cases in mainland China and Hong Kong show that this resurgence is “nor EMM-type specific [facteur de virulence spécifique aux streptocoques, NDLR]nor caused by the propagation of a single scarlet fever-producing clonesay the scientists. Instead, multiclonal scarlet fever outbreak strains are usually associated with the acquisition of mobile genetic elements carrying exotoxins [toxine bactérienne diffusant dans le milieu ambiant, NDLR].” Thus, the researchers suspect scarlet fever to have mutated and acquired via one or more prophages [virus de bactérie incorporé dans le génome de la bactérie, NDLR] which gives it more virulence. A hypothesis that remains to be demonstrated.
But the epidemic already seems to be there. Several regional scarlet fever outbreaks were reported in North East Asia in 2011 and in the UK in 2014. According to West France, Public Health England, the public health body in England, counted more than 1,143 cases of scarlet fever in Kent in 2018 compared to only 362 in 2017. A sudden and exponential increase. “This global resurgence of scarlet fever has caused a multiplication by more than 5 in the rate of contamination and more than 600,000 cases worldwide”, say the authors of the study.
On the eve of a new scarlet fever pandemic
However, the factors behind the resurgence of the disease remain a mystery. “The potential triggers for these new scarlet fever outbreaks remain uncertain, but accumulating epidemiological evidence indicates that the new prophages [génome de virus bactérien inséré dans la bactérie, NDLR] and antibiotic resistance elements have played an important role in the evolution, virulence and diversification of scarlet fever originating GAS strains in Northeast Asia” Australian researchers attest. Researchers suspect the superantigen responsible for “carrying” the group A streptococcus (GAS) bacterium may have given it some of its characteristics.
How to recognize it? Scarlet fever causes fever (38.5°C), sore throat and rash. Often benign, it is expressed mainly in children between 5 and 10 years old during the winter. There is no vaccine and scarlet fever is contagious even before symptoms appear. According to Social Security, a child has difficulty swallowing, has a fever and a characteristic appearance of the tongue — at first covered with a white coating, which then narrows in the center, then takes on a raspberry color — it is necessary to go to the pediatrician to treat the child with antibiotics to limit the duration of contagion. However, if the child has a high fever (above 40°C), sleepiness, unexplained crying, purplish marks on the skin or a general deterioration in his state of health, you have to take him to the emergency room. Scarlet fever was one of the leading causes of death in children in the early 1900s, but its incidence declined steadily during the 20and century. It seems that this outbreak of scarlet fever has been slowed down by the social distancing measures put in place to combat Covid-19, another pandemic.
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