Investigators continue to try and work out why more than 160 children in the UK have been hit by sudden onset hepatitis.
An update from the UK Health Security Agency (UKHSA) on Friday revealed an extra 18 cases of the severe liver condition were recorded as of 3 May (compared to 29 April), bringing the UK total to 163.
A review of questionnaires with families has found “relatively high numbers of dog-owning families or other dog exposures”, with 64 out of 92 cases where data was available talking about dog exposure.
“The significance of this finding is being explored,” the UKHSA said but added that “pet dog ownership is common in the UK”.
None of the children have died.
Watch: Possible link between dogs and spike in hepatitis cases among children examined
The UKHSA said a common virus called adenovirus may be causing the spike in hepatitis following the pandemic.
Adenovirus is the most often detected virus in the samples that have been tested.
However, as it is not common to see hepatitis following adenovirus infection in previously healthy children, investigations are continuing into other factors which may be contributing, the UKHSA said.
These include previous COVID infection or a change in the adenovirus genome itself.
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The most common symptoms in children in the UK are jaundice and vomiting, and the vast majority of cases are in those under five.
Dr Meera Chand, director of clinical and emerging infections at UKHSA, said: “It’s important that parents know the likelihood of their child developing hepatitis is extremely low.
“However, we continue to remind everyone to be alert to the signs of hepatitis – particularly jaundice, look for a yellow tinge in the whites of the eyes – and contact your doctor if you are concerned.
“Our investigations continue to suggest that there is an association with adenovirus and our studies are now testing this association rigorously.”
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Scotland’s public health agency first raised the alarm about unusual hepatitis cases in children on 6 April.
There have now been 14 cases identified in the country, including one additional case under investigation this week, Public Health Scotland director Jim McMenamin said.
The World Health Organisation (WHO) said earlier this week there were almost 300 probable cases of children with severe hepatitis detected in 20 countries worldwide.
Cases have been reported in Denmark, Ireland, the Netherlands, Spain, and the United States