The outbreak of mystery hepatitis in the United States will continue “throughout the summer” and many cases are still undiagnosed, a top virologist warned on Friday – as the global death toll hit 12 with five deaths in the United States.
Scientists are intrigued by the cause, but leading theories suggest that a type of adenovirus spread by touching surfaces contaminated by faeces is behind the disease.
Matthew Binnicker, director of clinical virologist at the Mayo Clinic in Minnesota, told DailyMail.com that cases will continue to emerge throughout the year as their transmission “does not tend to be seasonal.”
He warned that schools and kindergartens – where many children mingle – were the main centers for the virus to spread.
The Doctor. Binnicker also warned that many cases of hepatitis among children remain undiagnosed in the US because, in some cases, children will not be sick enough for their parents to take them to a doctor or hospital.
Most children with the mysterious hepatitis in the US have tested positive for adenovirus, but it is unclear whether the virus itself is causing the illness or the infection alongside another factor, such as a previous diagnosis of Covid.
Adenoviruses are relatively common among children, but until this year they were rarely associated with hepatitis. The common causes of the disease – hepatitis A, B, C, D and E virus – have all been ruled out.
At least 12 children have died from the mysterious hepatitis worldwide, with five deaths also reported in Indonesia and one in Ireland and one in Palestine.
More than 110 cases in 26 states have been reported so far, with 15 children becoming so seriously ill that they needed a liver transplant.
Globally, there have been 450 reported cases in 21 countries, mostly among children under 10 years of age. Most are in the UK (160), which first detected the outbreak.
Matthew Binnicker, a clinical virologist at the Mayo Clinic, warned that cases would continue to emerge this year.
Speaking exclusively to DailyMail.com, Dr. Binnicker said: “I wouldn’t be comfortable saying this outbreak has peaked.
“I would say that cases will continue to emerge over the summer period because we will continue to see children in day care where there is higher transmission.
‘This type of adenovirus we don’t usually think of as seasonal, we will continue to see cases throughout the year.’
The adenovirus for which most children with mystery hepatitis test positive is scientifically called type 41.
This infects the gastric system, causing symptoms such as diarrhea and vomiting.
It is spread by the fecal-oral route, or when someone touches a surface contaminated with feces and then touches their own mouth.
Asked if many more cases would be detected in the US, Binnicker warned that many would likely still be diagnosed because they were milder.
Q&A: What is the mysterious global hepatitis outbreak and what is behind it?
What is hepatitis?
Hepatitis is an inflammation of the liver that is usually caused by a viral infection or liver damage from drinking alcohol.
Some cases resolve on their own, with no ongoing problems, but a fraction can be deadly, forcing patients to need liver transplants to survive.
What are the symptoms?
People who have hepatitis often experience fatigue, loss of appetite, nausea, vomiting, abdominal pain, dark urine, pale stools, and joint pain.
They can also suffer from jaundice – when the skin and whites of the eyes turn yellow.
Why are experts worried?
Hepatitis is generally rare in children, but experts have already identified more cases in the current outbreak than they would normally expect in a year.
The cases are of “unknown origin” and also serious, according to the World Health Organization.
What are the main theories?
Experts say the cases could be linked to the adenovirus, commonly associated with colds, but more research is under way.
This, in combination with Covid infections, could be causing the spike in cases.
About three-quarters of British cases have tested positive for the virus.
British experts tasked with investigating the wave of disease believe the never-ending cycle of lockdowns may have played a role.
The restrictions may have weakened the children’s immunity due to reduced social mixing, leaving them at greater risk of adenovirus.
This means that even the ‘normal’ adenovirus could be causing the severe results, because children are not responding to it as they did in the past.
Other scientists said it may have been the adenovirus that acquired “unusual mutations”.
That would mean it could be more transmissible or better able to bypass children’s natural immunity.
New variant Covid
UKHSA officials have included ‘a new variant of SARS-CoV-2’ in their working hypotheses.
Covid has caused inflammation of the liver in very rare cases during the pandemic, although it has occurred in all ages, not isolated in children.
The CDC noted that environmental triggers are still being investigated as possible causes of disease.
These can include pollution or exposure to specific drugs or toxins.
“Hepatitis can occur on a sliding scale from taking an individual to be hospitalized to the other side, where it’s much lighter,” he said.
‘Inside [the mild] cases, may not prompt parents to take their child for investigation or hospital.
“Many of these children will experience symptoms of gastroenteritis such as vomiting, diarrhea and nausea, with some also experiencing an upper respiratory illness such as a cough or sore throat that precedes hepatitis.
‘Those who develop hepatitis will see changes in their skin color, so some develop symptoms of jaundice or yellowing of the skin… ranging from very noticeable to very subtle changes.
‘The white of the yellow eye is also very apparent and parents are very shocked sometimes, but other times it is very subtle and may not be noticed.’
He said that with about 90% of children who went to the doctor being hospitalized, that would mean there is only a “small percentage” who are not sick enough to go to the doctor.
He added that it was still very It is too early to say whether the US would detect the most cases in the world, being currently in second place.
But he said that because the country has such a large population, it suggests there is ‘much more here than in other countries’.
The UK – home to 67 million people – has recorded the highest number of cases in the world so far, with more than 160.
But the US — home to nearly five times as many people or 329 million — had the second highest case count, with more than 110.
Both countries detected more hepatitis than others due to stronger disease surveillance systems.
He said cases of hepatitis that went undiagnosed but got better on their own shouldn’t worry parents as they are unlikely to have long-term effects.
But every parent who is worried about their kids should take them in for a checkup.
Binnicker directs the Mayo Clinic’s clinical virology department.
He contacted the Centers for Disease Control and Prevention (CDC) to offer help in testing patient samples for adenovirus.
But for the time being, he said the offer was not accepted, likely because there were only a relatively small number of cases so far.
Yesterday Missouri updated its count of hepatitis cases reporting ten patients.
And North Carolina more than quadrupled its count from two cases to nine.
Both states were previously known to have cases of hepatitis, although they have now provided updated figures.
It’s unclear how many of them have already been included in the CDC’s count of mysterious hepatitis cases.
Most cases in the US were reported from October to March.
But this week Hawaii said it had a case that was hospitalized for a few days in late April.
There are now confirmed or suspected cases in 26 states. They are: Alabama, Arizona, California, Colorado, Delaware, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Louisiana, Massachusetts, Michigan, Minnesota, Missouri, North Carolina, North Dakota, Nebraska, New York, Ohio, Pennsylvania, Tennessee, Texas, Washington and Wisconsin.
At least one case has also been reported in the territory of Puerto Rico.
The CDC declined to reveal where the five US deaths took place, citing “confidentiality issues”.
But at least one was in Wisconsin, where the Department of Health confirmed last month that it was investigating a fatality linked to the disease.
There have been around 350 cases of ‘severe hepatitis of unknown origin’ in children reported in 21 countries since April.
At a press conference last week, the CDC’s deputy director for infectious diseases, Jay Butler, said most young people have “fully recovered” after the illness.
He said scientists are still investigating the cases to establish a cause, but that adenoviruses are at the top of the list.
Scientists are confused about what is causing the unusual illness, but the leading theory is that it is triggered by a group of viruses that normally cause the common cold.
Common viruses that cause hepatitis: Hepatitis A, B, C, and E viruses; were not detected in any of the reported cases worldwide.
Scientists are investigating whether a mutated strain of adenovirus has evolved to become more severe or whether a lack of social mixing during the pandemic has weakened children’s immunity.
They were also unable to rule out an old Covid infection.
In a bizarre twist, health officials are also investigating whether exposure to a ‘pet dog’ could be to blame for the illness.
The UK said it was looking into this as a cause after finding that more than half of hepatitis patients had been exposed to dogs or had them at home.
But experts have warned that this seems a bit ‘far-fetched’ because dog ownership is so high in the UK.
Covid vaccines were ruled out as a potential cause of the disease because the vast majority of sick children were not eligible for jabs.
In new guidance this week, the US CDC told doctors who treat children with hepatitis to collect liver samples for analysis.