so in general when you hear the term
epidemiological transition what people
are referring to is this change in the
burden of disease from infectious
disease or communicable disease to non
communicable disease or chronic disease
and we're seeing this process at the
moment predominantly in low and middle
income countries now to understand this
better what we're going to do is we're
going to take a look at the history of
epidemiological transition so how did we
get to where we are right now and we're
gonna take a look at what the future has
in store for us because this process is
far from over
in 1971 Abdullah Marin proposed his
theory as to how it is that patterns of
mortality have changed over time
Ameren proposed that there's been three
phases of epidemiological transition so
let's take a look at these phase 1
pestilence and famine from prehistory to
the mid 18th century infectious disease
was the major cause of death especially
once people started living in close
proximity in city states travel and
trade between city states allowed for
diseases like plague to have a
devastating effect on the population
plague killed about 25 million people
that's about a third of the population
in Europe in just five years and during
this time they were of course other
important causes of death things like
war and famine killed lots of people and
low standard of living poor hygiene and
no access to effective healthcare were
important drivers of death and disease
at this time phase to the age of
receding pandemics
between the middle of the 18th and the
middle of the 20th century with the
Industrial Revolution came improved
nutrition sanitation and medical care
this resulted in massive reduction in
the spread of infectious disease and
epidemics and this of course didn't
apply to all people many people living
in squalid conditions in cities died of
diseases like cholera phase three
degenerative disease as of the middle of
the 20th century due to vaccines
antibiotics and improvement in the
social determinants of health we've seen
an increase in life expectancy and with
that we've seen an increase in the
diseases that are prevalent amongst the
elderly things like heart disease stroke
cancer and other chronic diseases a more
sedentary lifestyle together with
dietary changes have also contributed to
an increase in obesity which itself is a
risk factor for things like diabetes
heart disease cancer etc
cetera just to give you a sense of the
scale of the problem non communicable
disease today kills 40 million people
every year that's about 70% of all
deaths globally 15 million of these
people are relatively young between the
ages of 30 and 69 and 80% of these
premature deaths many of which are
preventable occur in low and middle
income countries tobacco alone accounts
for 7.2 million deaths every year and
this is projected to increase over the
coming years now the problem in many
developing countries is that this
process of epidemiological transition is
taking place firstly very quickly and
secondly is taking place at a time when
there are existing social disparities
and that means that what's happening
there is we're seeing a double burden of
disease we're seeing existing infectious
diseases and that's still a problem and
we're seeing the emergence of huge
numbers of chronic disease and these
countries health systems due to resource
constraints are just not geared up to
deal with this double burden of disease
for a country to address non
communicable disease there's a couple of
challenges let's take a quick look at
why it's tricky patients require ongoing
treatment for chronic conditions so it's
not as simple as just giving an
antibiotic and walking away prevention
is difficult and prevention requires
lifestyle changes people living in poor
countries often live in extremely
challenging circumstances and they don't
have the luxury to spend time on
Wikipedia figuring out how to design a
lifestyle diet low in trans fats to
manage chronic disease you often need
multidisciplinary teams and these often
just don't exist in low resource
settings managing chronic disease
requires self management and education
and this has proved tricky even in rich
countries now this process of
epidemiological transition is far from
over
it's going to continue and it's going to
continue in a very interesting way that
actually affects all of us
even people living in high-income
countries so stay tuned and find out
more
but first a big thank you to the
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so we've said that this process of
epidemiological transition isn't over
let's take a look at what the future
holds I think that the most important
change that we're going to see in the
medium to long term is the re-emergence
of infectious disease even in
high-income countries this is going to
be driven by two things firstly
increasing antimicrobial resistance and
secondly the increasing emergence of
novel zoonotic infections so let's just
take a look at each of these
increasingly we're seeing infectious
diseases that are difficult and in some
cases impossible to treat with
antibiotics and other antimicrobials so
in a sense there's this ongoing race
between humans trying to develop new
drugs to treat infectious disease and
microbes developing new resistant
strategies and let's be clear with
respect to this particular race we are
on their turf microbes have evolved over
billions of years to be very very good
and adapting to changes in micro
chemical environments in 2016 we saw
nearly half a million new cases of multi
drug-resistant tuberculosis we seeing
resistance emerging to HIV treatment to
malaria treatment we're seeing increased
incidence of methicillin-resistant
staphylococcus aureus and carbapenem a
is producing Enterobacteriaceae and
other resistant organisms in hospitals
without question this increase in
antimicrobial resistant organisms is
going to be one of the biggest public
health challenges facing us in the
future and to make matters worse we're
seeing an increase in the incidence of
novels or notic infections a zoonotic
infection happens when a microbe jumps
from an animal hosts to infect humans
and in just the last few decades we've
seen HIV we've seen sighs we've seen
MERS Coby we've seen in bola we've seen
many many novel zoonotic infections jump
from animal hosts to humans and then
spread across country borders and given
existing and increasing population
density and the fact that in any one
year more than a billion people move
from one place to another we're likely
to see more and more of these novels and
notic infections and other infections
spread across country borders and
threaten global health security now I
have created a video on pandemics so if
you're interested in global health
security check that out subscribe to
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