the number of coronavirus cases has
sharply risen following changes in the
way it's diagnosed the World Health
Organization is seeking clarity from
China after 15,000 more infections were
recorded on Wednesday 254 more deaths
have been confirmed that's more than
double the previous Daily Record almost
all of them are in who Bay Province
almost 60,000 people in China are now
known to be infected and the number of
those killed stands at more than 1300
also officials in Vietnam have placed
the town of 10,000 people under
quarantine following five cases of virus
infection their Vietnam declared a
public health emergency over the
epidemic at the beginning of this month
and in Japan a cruise ship the diamond
princess remains quarantined in Yokohama
after an outbreak of the virus on board
it's now thought 218 passengers and crew
members are among those infected our
correspondent Rupert wingfield Hayes is
in the port so the number of infections
on board the diamond princess behind me
here in Yokohama has again jumped today
44 new cases confirmed today that
followed 39 cases yesterday and that
brings the total number of infections
from the ship to 218 and that means as
we know now that this is now the single
biggest outbreak of the Cova 19 virus
anywhere outside mainland China the
Japanese government has made a small
concession to the criticism that has
been building of its the way that its
handling this outbreak they've said that
very elderly people over the age of 80
will be allowed to disembark if they
have underlying health conditions or if
they are in one of those inside cabins
that don't have any outside windows or
balconies so expect to see that start
happening maybe tonight or on Friday but
there are many questions that remain
first of all obviously is our infection
still taking place is the virus still
circulating around the ship no one
really knows and the other big question
is why still has the Japanese government
not managed to test all of the
passengers and crew on board well let's
get you some real expertise now David
Heyman is a
of infectious disease epidemiology at
the London School of Hygiene and
Tropical Medicine David previously
directed the World Health Organization
response to the SARS outbreak in 2003
David first I want to talk to you about
the mortality rate the reports were
seeing put the mortality rate of this
virus at about two percent that's right
and that would be at the level of
influence of seasonal influenza each
year they're about one to two percent of
people who died unfortunately but what's
happened in China is the case definition
that is the way they define a disease
has included pneumonia and so they're
missing all the less severe cases of
disease and only looking at those that
are most severe so of course the
mortality is higher among those people
so the case definition recently has been
changed in China and they're now
including less severe symptoms as well
in their diagnosis and something that's
important now is the way they're testing
it has been to do with these lab kits
beforehand and and what's been the
problem with those well they've been
using test kits that detect nucleic acid
the problem with them is that it takes a
long time to get a result longer than
they want it takes some times a day for
them to get a result does it does it
require some expertise to administer and
and to read absolutely it requires both
expertise and skill and and making sure
that there isn't contamination from the
laboratory around it so what they've
done recently is two things they've
developed a more rapid point-of-use test
for nucleic acid which they've rolled
out it's not clear how effective this is
but they're using it and in addition
they've changed the way they diagnose
and in some instances they're just
diagnosing based on symptoms and an
x-ray which means there's no nucleic
acid diagnosis so does that mean the
number of diagnoses the number of
confirmed cases is bound to jump
absolutely because not only are they
finding cases of coronavirus but they're
finding other diseases that also are
other infections rather that also cause
pneumonia so they're seeing an increase
in the number of cases and a decrease in
what we call the specificity of
diagnosis so what in in kind of real
world terms David what does that this
mean does it mean that just that the
clinicians are able to spot coronavirus
better or that we should be alarmed the
way in which it is spreading on the rate
at which it's spreading well certainly
it spread throughout China and China's
making every effort they can in the way
that they do best to stop the disease
what's important though is those 24
sites outside of China and also the
cruise ships that's where the
information about how severe the disease
is we really come from because the
patients here are being monitored very
closely as are their contacts and we're
learning a lot as we see what happens in
these situations which hopefully will
lock down the disease in these countries
and not permit it to spread further is
there an issue here in that China's
obviously Communist Party state controls
you know command and control to a
certain extent for other countries not
the case and it might be that there's
less grip on the way centers are run the
ability to to build the medical
facilities as well well clearly in the
SARS outbreak China had the same type of
a lockdown and they rapidly got rid of
the infection in other countries where
there was a different approach it
sometimes recurred after they thought
they had it controlled so there are
benefits of authoritarianism but there
are also disadvantages and the
disadvantages of course are an
infringement on human rights how would
you describe your level of concern about
the corona virus outbreak I think we're
all concerned about what we don't know
right we know so far what's happening
and what we can see but what we don't
know is the real potential of this virus
whether or not this eventually could
become a disease endemic in humans like
TB influenza or others because influenza
also comes from animals into humans and
it sometimes becomes a permanent
resident David Heyman really appreciate
you coming in today thank you very much
thank you