Experts said the recent infections are a striking reminder
of the 'increasing' threat posed by avian influenza
GLOBAL HEALTH SECURITY CORRESPONDENT, IN BANGKOK3 March
2023 • 11:58am
A man carries live chickens on the back of his bicycle at a wet market in Shanghai CREDIT: Corbis via Getty Images/Qilai Shen
A woman in China was recently hospitalised with the
strain of bird flu that’s increasingly infecting mammals across the world, it
has emerged.
The H5N1 case – in a 53-year-old in Jiangsu province, just
north of Shanghai – comes after a young girl died last week and her father was quarantined in
Cambodia, causing global alarm amid initial fears human-to-human transmission
was involved.
That turned out not to be the case, but experts have warned
that all three infections are a striking reminder of the threat of avian
influenza at a time when H5N1 is causing an unprecedented outbreak in birds
and, increasingly, mammals.
“The risk [for humans] is increasing in the sense that there
is a lot of virus in poultry and wild birds,” Prof Munir Iqbal, head of the
Avian Influenza Group at The Pirbright Institute and a member of the
government’s new modelling group for bird flu, told the Telegraph.
“The virus can change at any time, and therefore the risk is
higher when there’s more in the environment. That doesn’t mean [a human
epidemic] is imminent… but no one has control of the virus… so you can say
there is a serious risk,” he said.
According to the World Health Organization, China informed
the agency about the latest case on February 24, but it was only reported this
week. The 53-year-old woman – who has a history of contact with poultry – fell
ill on January 31, and was hospitalised on February 4.
Unlike the cases in Cambodia, which were linked to a strain
of H5N1 that has been endemic in the region for a decade, the
Chinese woman contracted the variant currently behind an unprecedented global
outbreak in birds.
“Genomic sequencing showed that she was infected with H5N1
clade 2.3.4.4b, which is widely circulating in birds at the moment,” said Dr
Sylvie Briand, director of epidemic and pandemic preparedness and prevention at
the WHO.
“Since 2020, an increased number of avian influenza
outbreaks have been reported in wild birds and poultry globally, and we can
expect additional sporadic human cases,” she added.
At a press conference last week, Dr Briand also said that
the UN agency is “really concerned” about the potential for human-to-human transmission to emerge.
Part of the current unease stems from mounting cases in
mammals, including signs in mink and sea lions that the 2.3.4.4b clade is
becoming better at spreading between them.
This week, Peru announced that the death toll from H5N1 had
jumped to 3,500 in sea lions – five times as many as previously reported. Their
symptoms were mainly neurological, such as tremors, convulsions and paralysis.
While it is unclear how they were infected, researchers said the size of the
outbreak means they cannot rule out mammal-to-mammal spread.
“If transmission between mammals have started, the virus has
changed and this could increase the risk for human health,” Dr Pablo Plaza, an
expert in veterinary public health and epidemiology at the National University
of Comahue in Argentina, and co-author of the first pre-print describing the
sea lion outbreak, told the Telegraph last week.
“Until now, this risk seems to be low – however, we must be
alert since [the] virus is changing all the time. Several changes in the virus
are needed to adapt to human-human transmission, so hopefully they will not
occur,” he added.
The latest H5N1 case in China comes after a woman died from
the virus in November in the southern province of Guangxi. This week, the
country has also reported cases of two other types of avian influenza – H5N6
and H9N2.
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https://www.telegraph.co.uk/global-health/science-and-disease/bird-flu-found-chinese-woman-cambodia-scare/
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