The enigmatic acute hepatitis whose origin is unknown and which apparently attacks young children – mostly as young as 5 years old – is already in Latin America.
Until Tuesday they were six Latin American countries that they had reported probable cases of childhood acute hepatitis of unknown origin, the advisor on Disease Prevention and Control of the Pan American Health Organization (PAHO), epidemiologist Enrique Pérez, told BBC Mundo.
In those six countries – which Pérez preferred not to say what they are – they were detected. 23 cases. In addition, there are others 53 suspects under consideration.
There had been no deaths in the region of confirmed cases or those who should receive a liver transplant until Tuesday, May 17.
The first Latin American country to register a suspected case was Argentina, although it is still under investigation to confirm whether its origin is unknown.
It happened on May 5, when the Ministry of Health of that country reported that an 8-year-old boy was hospitalized in the city of Rosario (300 kilometers northwest of Buenos Aires). It had to be transplanted and was evolving favorably.
He was joined by eight more cases.
Costa Rica reported the case of a 2-year-old girl with acute hepatitis who tested positive for adenovirus. Days later she was discharged.
The Central American country reported after a 4-year-old girl whose hepatitis had unknown origin, although in that case the adenovirus test was negative, local media reported.
Brazil reported on Saturday the detection of 44 possible cases, of which three were ruled out and 41 were under study.
Mexico said it had detected five possible cases, but two were already dismissed, while in Panama, two cases were being studied.
Puerto Rico reported two suspected cases; one was a 2-year-old girl who died on Monday.
The first alert about the disease in children was given by the United Kingdom on April 5.
As of May 15, the World Health Organization (WHO) had received reports of 429 cases of childhood acute hepatitis of unknown origin in 22 countries, while it had another 40 cases under study.
75% were under 5 years of age, 15% had to be admitted to an intensive care unit and most were in Europe.
In the world there were six children who died from this cause and 26 required a transplant.
What is acute hepatitis?
Microscopic image of the virus that causes hepatitis A.
Hepatitis is a inflammation of the liver. When it occurs abruptly, it is called “acute hepatitis.”
Causes include infection (by a virus or bacteria), poisoning (alcoholic, by substances or drugs), and the immune system.
In some cases, such as hepatitis B, C, and D, the infection can become chronic.
“Acute hepatitis has different symptoms: gastrointestinal, such as diarrhea or vomiting, fever and muscle pain, but the most characteristic is jaundice, a yellow coloration of the skin and eyes,” said infectologist Leandro Soares Sereno, advisor for the prevention and control of viral hepatitis at PAHO.
What is known so far about the new hepatitis?
The European Centre for Disease Prevention and Control (ECDC) said acute hepatitis may take time to develop after the appearance of the first symptoms, so there may be a delay in the notification of cases.
He added that once there is suspicion, confirming it through studies also takes time.
That the hepatitis is of unknown origin implies that it cannot be attributed to the most frequent variants -A, B, C, D or E-, all studied in the past, and neither to an intoxication or an autoimmune effect.
“Common exposures to toxins, drugs and COVID vaccination have not been identified as a cause,” Philippa Eastbrook, a specialist with WHO’s global hepatitis programme, told a news conference on Tuesday.
“The key to the hypothesis [del origen es sobre] links between adenovirus and SARS-CoV-2 and, more importantly, how these two infections may be working together as cofactors, either by increasing susceptibility or creating an abnormal response,” Eastbrook said.
The SARS-CoV-2 coronavirus is the cause of covid-19.
What is being studied with ma”Whether a previous covid infection in children, perhaps some time ago, may have persisted and remained in the gut, and then a subsequent adenovirus infection has caused the immune system to activate and cause inflammation” in the liver, the hepatitis expert added.
70% of the cases tested as of May 10 had tested positive for adenovirus, and of these most were for adenovirus type 41. 18% had tested positive for covid.
However, it is not yet clear whether all the cases identified after the alert are part of a real increase compared to the initial rate of hepatitis of unknown origin in children.
Experts are investigating a possible link to an increase in infections with adenovirus, a common cause of childhood illness.
It is also being studied whether it has any link with COVID-19 – whether a current or previous infection increases the risk of this disease in some children – or anything in the environment.
The latest ECDC assessment, published on 13 May, also points out how main hypothesis to an adenovirus infection.
According to the European body, it would be mild under normal circumstances, but in these cases it triggers a more serious infection or liver damage mediated by the immune system.
Other possible causes were not excluded as hypotheses, but are considered less plausible.
The disease is rare and evidence on human-to-human transmission remains unclear.
What is adenovirus 41?
Adenoviruses are a family of viruses that spread from person to person and cause more often respiratory diseases, but, depending on the type, they can also cause other Ailments such as gastroenteritis (inflammation of the stomach or intestines), conjunctivitis, and cystitis (bladder infection), according to the U.S. Centers for Disease Control and Prevention (CDC).
Adenovirus type 41, also called F41, typically presents with symptoms such as diarrhea, vomiting, and fever, often accompanied by problemrespiratory.
While there have been case reports of hepatitis in immunocompromised children with adenovirus infection, it is unknown whether adenovirus type 41 is a cause of hepatitis in children who were healthy.
Until now the origin of this new ailment is unknown.
The CDC believes adenovirus may be the cause of these reported cases, but researchers are still learning from this infection. To do this, they want to rule out other possible causes and identify factors that may have contributed.
“In general, the infection has a limited duration and does not evolve to worrisome conditions, although there have been rare cases of severe adenovirus infections that have caused hepatitis in immunocompromised patients or people undergoing transplants. However, these children do not respond to this description, as they were previously healthy,” said PAHO’s Soares Sereno.
