the trail of a virus?

Hepatitis is an inflammation of the liver, in reaction to viruses, toxins (drugs, poisons, etc.), autoimmune or genetic diseases. Often benign, its main symptoms – fevers, diarrhoea, abdominal pain, jaundice – generally resolve quickly. More rarely, they can lead to kidney failure.

unexplained hepatitis

The United States is far from being the only country affected by this phenomenon of unexplained hepatitis: dozens of cases have been identified all over Europe, raising fears of a new epidemic. First reported in Scotland at the end of March, the number of cases recorded worldwide is currently 191 (111 in the United Kingdom, 55 in 12 other European countries, 12 in the United States, 12 in Israel and 1 in Japan), according to the European Center for Disease Control and Prevention (ECDC). Affected children ranged in age from one month to 16 years old, but most were under 10 years old, and many under 5 years old. None had comorbidities.

On the same subject

Mysterious hepatitis: adenoviruses involved?

A total of 169 serious cases of hepatitis have been detected in children as of April 23. The United Kingdom is the most affected, but cases have also been reported in a dozen European countries and as well as in the United States in particular. In France, two cases have been reported. Most hospitalized children are between 1 and 5 years old. Seventeen of them required liver transplants and one child died in the UK.

Rather commonplace viruses, adenoviruses are generally rather known to cause respiratory symptoms, conjunctivitis or even digestive disorders. Transmission occurs by the faecal-oral or respiratory route, with epidemic peaks often in winter and spring, and more often in communities (nurseries, schools, etc.). The majority of humans are infected before they are 5 years old. But their role in the development of mysterious hepatitis is unclear.

“Right now we think an adenovirus could be the cause of these cases, but other environmental factors are still being studied,” said the Centers for Disease Control and Prevention (CDC), the main federal agency for United States public health. More specifically, the CDC points to the so-called “type 41” adenovirus, hitherto best known for causing severe gastroenteritis. If these adenoviruses are well identified as causes of hepatitis, they were so far only in immunocompromised children.

After more than two years of pandemic and barrier gestures, the question of an immune “debt” which would make certain children more fragile is also raised by certain scientists, without certainty.

Europe concerned

The European Agency for Diseases (ECDC) classified this Thursday as a “worrying public health event”, these unexplained cases of acute hepatitis, while acknowledging that it was not able to accurately assess the risk. “Considering the unknown etiology (the cause of the disease, editor’s note), the affected pediatric population, and the potentially serious impact, this constitutes at this stage a worrying public health event”, alarms the ECDC, in its first estimate public risk since the onset of the disease.

“The disease is quite rare and evidence of human-to-human transmission remains unclear. Cases in the European Union are sporadic with an unclear trend”. The risk for children in Europe “cannot be estimated precisely”, notes the agency again. “Nevertheless, considering the reported cases of acute liver failure, with cases requiring transplantation, the potential impact for the pediatric population is considered high.”

The main “working hypothesis” is, here too, that the disease is linked to adenoviruses. “An adenovirus infection, which would be mild under normal circumstances, would trigger a more severe infection or immune-mediated liver injury,” according to this lead. Other causes, in particular toxic, “are still the subject of investigations and have not been excluded but are considered less plausible”, punctuates the ECDC.

WHO recommendations

While most of the cases were detected at the end of March, it was on April 15 that the World Health Organization (WHO) issued the alert and urged the countries concerned to launch a major investigation in order to “determine the etiology of these cases and guide clinical and public health actions”. Pending the results of this work, the WHO recalls that regular hand washing and wearing a mask can prevent adenovirus contamination and other common infections.

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