First case of H10N3 avian influenza
In China, a human case of H10N3 bird flu has been
confirmed in Jiangsu province.
This virus, which is not very pathogenic in chickens,
does not seem to be able to be transmitted between humans.
The National Health Commission (NHC) of China
announced, this Tuesday, June 1, 2021, a human case of H10N3 avian influenza.
That was in Jiangsu province, in the east of the
country.
Influenza viruses that infect poultry are regularly
transmitted to humans through close contact with sick animals.
In the case of the H10N3 strain, this is the first
time it has been isolated in humans.
H10N3 bird flu virus isolated in a human
The sick person presented to a hospital in Zhenjiang
on April 28 with fever and other symptoms.
Sequencing of the virus taken from the 41-year-old man
indicates that it is the H10N3 strain, belonging to the influenza A group of
viruses.
Unlike the H5N1
strain, the latter is not very virulent in poultry and does not seem to be able
to effectively infect humans.
The Chinese National Health Commission considers that
the risk of large-scale spread of the virus is very low.
The circumstances of the human infection are not
known, but it appears that he breathed in microdroplets produced by infected
chickens on a farm.
Also, it could be produced through direct contact with
them.
The patient, whose health condition has improved, and
his relatives have been placed under medical surveillance.
About H10N3 avian influenza
H10N3 is a low pathogenic or relatively less severe
strain of the virus in poultry and the risk of widespread was very low.
In the past 40 years through 2018, there were only
about 160 isolates of the virus, which have been reported.
Namely in wild birds or waterfowl in Asia and some
limited areas of North America, and none had been detected in chickens so far,
he added.
Analysis of the virus' genetic data will be needed to
determine whether it resembles older viruses or is a new mixture of different
viruses, Claes said.
Several others strains of avian influenza viruses are
present in China and some sporadically infect people, usually those who work
with poultry.
There have been
no significant numbers of human bird flu infections since the H7N9 strain
killed about 300 people in 2016-2017.
Fortunately, the NHC said that no other cases of human
infection with H10N3 have been previously reported worldwide.
History of human infection with birth flu viruses
Normally, avian viruses do not infect species other
than pigs and birds.
The first documented case of human infection occurred
in Hong Kong in 1997.
When an H5N1 strain caused severe respiratory illness
in 18 people and death in 6.
This infection coincided with an outbreak of highly
pathogenic avian influenza, caused by the same strain, affecting poultry in Hong
Kong.
Extensive investigations into this outbreak revealed
that close contact with live infected poultry was the source of human
infection.
Genetic studies subsequently established that the
virus had passed directly from birds to humans.
There was limited transmission to health care workers,
but no severe form of the disease.
The rapid culling - within three days - of all poultry
in Hong Kong, estimated to be about 1.5 million birds.
It reduced the possibility of further direct
transmission to humans and may have averted a pandemic.
This event alarmed health authorities as it was the
first time that an avian influenza virus had been transmitted directly to
humans.
It was caused severe illness with high mortality.
These concerns were rekindled in February 2003, when
an outbreak of H5N1 avian influenza in Hong Kong resulted in two cases and one
death.
Another child in the family died during that visit,
but the cause of death is unknown.
Two other avian viruses have recently caused illness
in humans.
An outbreak of highly pathogenic H7N7 avian influenza
began in the Netherlands in February 2003.
It resulted in the death of a veterinarian two months
later and a mild case in 83 people.
Mild cases of H9N2 avian influenza first occurred in
children in Hong Kong in 1999 (two cases) and mid-December 2003 (one case).
H9N2 is not highly pathogenic to birds.
