This course proposes an overview of current global health challenges drawing on the insights of several academic disciplines including medicine, public health, law, economics, social sciences and humanities. This interdisciplinary approach will guide the student into seven critical topics in global health.
Neglected Tropical Diseases (NTDs): Key Issues and Challenges in Global Health by François Chappuis
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En provenance du cours de University of Geneva
Global Health: An Interdisciplinary Overview
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À partir de la leçon
Emerging Trends in Global Health: Infectious Diseases
There are 7 parts to module 3. Lessons 3 & 4 are both introductory sections that describe key concepts necessary to understand infectious diseases and how we deal with them. Lesson 5 constitutes the core lesson of module 3. This lesson focuses on the current global situation and future challenges for the most prominent infectious diseases of the world. In lessons 6-9 we discuss neglected tropical diseases, re-emerging infectious diseases and epidemics/pandemics. Finally, lesson 10 and 10b summarize module 3 in a set of key conclusions.
Rencontrer les enseignants
Rafael Ruiz De CastañedaInstitute of Global Health - Faculty of Medicine
University of Geneva
Antoine FlahaultProfessor of Public Health and Director of the Institute of Global Health (Faculty of Medicine, University of Geneva) and co-Director of Centre Virchow-Villermé (Université Paris Descartes)
University of Geneva and Université Paris Descartes – Sorbonne Paris Cité
[MUSIC]
Good morning.
Good afternoon.
Good evening.
Good night, perhaps.
In the minutes that come let's talk about neglected tropical diseases.
So I think diseases you all know what it means.
A breach in health, illness.
Tropical, you guess what it means.
These are a group of disease that mainly occurs in the tropics,
not exclusively but mainly.
But neglected is probably the term that needs most to be defined, and
that's what we are going to try to do in the coming minutes.
Whatever definition you find, and you use,
yes this is a group of diseases that are mainly infectious,
not exclusively, think of snake bites, for example.
There are many occurring in the tropics as I said.
There are many occurring in rural population or urban slums,
but there is one common denominator that links all these diseases,
is poverty, disadvantaged, poor.
Because this is really what links all these patients suffering from these
conditions, poor and neglected.
So what are these neglected tropical diseases?
In fact it is a group, a quite heterogeneous group of diseases.
Some of them are very numerous.
Almost a billion people may suffer with intestinal worms.
On individual side, they don't kill, but
they can slow the growth, mental or physical growth of children.
Some diseases are more rare, but
they can kill either all those who are infected, like sleeping sickness,
or or a substantial proportion of them like disease.
And some are chronic, disfiguring,
disabling diseases like like ulcer,
like the long term consequences of snake bite, and like leprosy.
Is it really an important public health problem or is it anecdotal?
So if we see the left part of this slide,
you see that neglected tropical diseases when they are put together with malaria
represent a substantial proportion of
years of life lost which is one of the two components of.
So there is no doubt even though these diseases are under reported
that they represent a clear global health burden for
populations especially in tropical settings.
If you see, for example, data that comes from the Institute of Health Metrics and
Evaluation, if you take some of the countries like here Sudan,
the right part of the slide in position 20.
When we see this disease that most of you probably don't know is so
it's surprising disease that affects people living in rural areas or
displaced people and kill those who are affected.
NTD also is a humanitarian challenge in some contexts, in some settings.
For example, in South Sudan a couple of years ago, there has been large
outbreak of kala-azar of leishmaniasis with thousands of death and cases.
In fact in the 1990s, it has been a real humanitarian
disaster among displaced population victim of conflicts,
with an estimated hundred thousand death due to kala-azar.
A big question I told you before is,
how do we define the word neglected and first of all, neglected by whom?
Of course the first thing that comes to mind is the pharmaceutical companies,
who are not so keen to keep the production of existing drugs for these diseases.
And not so keen to spend money to develop new drugs.
But that would be too easy to only blame pharmaceutical companies.
First of all we also have to blame those who produce diagnostic tests and
develop diagnostic tests,
because the development of diagnostics has been very poor over the last decade.
But once again, it's a multi-stakeholder responsibility,
and in fact we absolutely need to point as well
the lack of commitment of national policy makers in other countries.
Why is that?
Because people who are affected by neglected tropical diseases,
they have no political voice.
They live in far rural areas.
Very far from the capital cities, so this is not political
interesting for politicians to fight for these people, so
that has been and it still is a major problem.
They've been neglected also by funders.
Either public funders, there have been no global fund for neglected tropical
diseases, no U.S. president incentive for neglected tropical diseases.
And also, to a lesser extent, from philanthropical private funders,
and I should mention also the academic centers,
like universities, both in endemic and
none of them in countries like in my country Switzerland, Geneva.
Outside optional courses these diseases absolutely not covered in the curriculum.
And finally by the media there has been insufficient coverage of
these diseases that allowed for proper advocacy activities.
So this wall that is
painted a little bit in black here is a little bit less black now.
There has been some progress,
that I will describe later, from these different stakeholders.
To illustrate this lack of development of new drugs, look here.
Out of over 1,500 new drugs that were released,
developed and released in the market, 21,
1.3% were developed for tropical diseases and
tuberculosis that represent 12% of the global health burden at that time.
So that's what we call the fatal imbalance.
How do we control these diseases?
There is a new medical approach.
And as we will see, if we want to have a sustainable control, elimination, or
eradication of these diseases, we will need to have a much more multisectorial
approach, which is of course a key concept of global health.
We can control some of these diseases by preventive chemotherapy.
And I will explain with an example what this means.
We can control some of these diseases by intensified case management.
Here again, I will show you an example what exactly this means.
Some of these diseases are transmitted by insects or arthropods.
We call them vector borne diseases so we can control with,
by controlling the vector that transmit the disease.
Then some of these illnesses can be controlled by
provision of safe water or safe food, and proper hygiene.
So, here we enter in a much more multi sectoral domain.
Because this is not something that will be solved by nurses or
doctors or medical staff.
And finally, veterinary public health has to enter into the game for
some of these diseases because animals can be the reservoir
of some of the infectious agents.
And we will never be able to control the illness in humans if
we don't control it in animals.
This is the case for Cysticercosis or for example.
One common denominator as you can see, all these control measures
that can be implemented, one that cannot is vaccine
because there is no vaccine for none of these diseases.
So, that contrasts with some of the other infectious diseases.
So, let me take an example of what we call preventive chemotherapy.
Let's take onchocerciasis.
We call it a cerebral blindness.
This disease affects parts of the West and
Central Africa and also some tiny parts of Latin America.
How is it transmitted?
This is a small fly, a black fly that bite a human.
They develop, this black fly in the river
usually when there is a fast stream of the river.
And when they bite they transmit a larva which develops in to adults
in the human body.
These adults, the female live in the nodules on the some parts of the body.
And they produce thousands and thousands of larva that situate in the skin.
Producing a very disabling itching and skin lesions,
but also this lava goes in the eye and when they die they produce and
inflammatory reaction that in the long run can lead to blindness.
So, how can we control this disease?
Like all parasite they have a cycle.
And the objective is to break this cycle at a given point, or
at several given point.
So, until in the 1970s, and a couple of decades later,
the strategy was focused most on vector control.
There were insecticides spraying most of the time by helicopters
on the areas where the black fly was developing.
But now, the strategy has switched, in the current control programs,
to a mass distribution of a drug called ivermectin
that is donated by the producer of this drug, a mass donation.
And every year, the people at risk receive a dose of ivermectin that
kills the larva that circulate in the skin or in the eye.
So, it decrease the symptom and also it breaks the transmission
because the black fly that bites someone with no
more larva in the skin cannot transmit the disease to others.
So, this is what is called preventive chemotherapy.
The other approach intensified case-management
our group of disease for which there is, of course as I said,
no vaccine, but also no facility to go for preventive chemotherapy.
Let's take sleeping sickness, for example.
This is a disease, a condition,
that only exist in remote part of Central and West Africa.
When I say remote, that's really remote.
And actually the hottest forest fire at the moment takes place also in
conflict areas.
You can see here this type of setting, yeah.
Very isolated hamlets, small villages in the forest,
which are barely accessible, even with motorbikes.
How this is transmitted, by a fly called a tsetse fly.
The parasite goes in the body, develops in the blood,
in the lymph, in the spleen, in the liver etc.
Multiply, and after a while goes into the central nervous system,
into the brain, and produce the symptoms that lead to the name of the disease.
People who actually sleep too much during daytime, but actually do not or
can't sleep during night time.
And it leads to death if it's untreated.
So, this disease cannot be controlled by
preventive chemotherapy because in affected areas you may have have
like 1 or 2% of the people who are affected.
So you are not going to treat the whole population for these 1 or 2%.
But this proportion will die if you don't treat.
So the objective, is to detect them,
to screen them, wherever they are in their villages.
So, that you can detect those who are infected and you can treat them.
Sounds easy, in practice it is not.
Why? Because the tools we have,
the diagnostic and the treatment are very impractical.
Look, this diagnostic tree.
You don't need to look absolutely in detail, but
globally you see intuitively that it's complicated.
You have to take blood to screen with the first test and
then if it's positive with this first test you have to look for
the parasite with a microscope so you need very trained technicians to do that.
And if you find the parasite and can find the disease.
Then you have to stage the illness
by doing the lumbar puncture to see if the brain is already affected.
Why? Because the treatment depends on the fact
the brain or not is affected.
So, this is really complicated.
And look at treatment.
Until the early 2000s, we were using this drug, Melarsoprol.
It's an arsenic-based derivative.
This drug was curing a certain proportion of patients, but
was also killing 3 to 6 or 7% of those who were treated.
And it was used for over like 80 years or something.
Now, we have, thanks to the mobilization of the rich or
of some NGOs like Doctors Without Borders.
And also a commitment from the pharma that produce Eflornithine and
another one producing nifurtimox.
These two drugs when combined together Is a much safer alternative.
It's a good treatment.
But it's still complicated because you need two infusions per day for seven days.
So you imagine how to give this in these remote rural areas where
you just have access, not even to a doctor or a nurse, but a nurse assistant at best.
So, this is why we need better tools for
some of these neglected tropical diseases.
To go from the current situation that you see here on the left,
complicated diagnostic tree, rather complicated treatment, to a much
simpler approach where you can apply what we call the rapid diagnostic test.
One of these tests where you stick the finger, collect the blood and
you look for the presence of antibodies.
And in 10, 15 minutes you have the result.
And then we need an oral, safe drug efficacious,
effective on both stage of the disease.
So you don't need to do this lumbar puncture anymore.
And you can treat the patients close to where they stay
at the primary healthcare level.
Touch now, there has been progress,
really significant progress, over the last ten years especially.
First of all, at WHO was created 2007, 2008, the department or
division that takes care of neglected tropical diseases.
And they came up, in 2010,
with the first WHO report that encouraged you to get on the WHO website.
And more recently, in very early 2012,
was released a road map by WHO for
most of the 17 of these neglected tropical diseases.
This road map is important.
It defines for 2015 and 2020 for
each of these in what is the objective in term of control.
Is it just to control or decrease the burden?
Is it to eliminate the disease?
Or even is it to eradicate the disease?
That's extremely useful for policy makers,
for funders, for implementors, in the new countries.
It gives really a thread to follow for these illnesses.
Another recent progress that is very significant is, there is no
way that the pharmas will assume all the development of drugs for these illnesses.
And frankly, this is not their role.
And instead of keeping in a blaming attitude,
I think people ended up to understand that it is better to have them as partners.
And partners within what we call product development partnerships, PDPs.
These are initiatives that put people and stakeholders together.
Pharmas, academia, small companies that do pre-clinical testing,
people from ministries of health and so on.
This initiative's catalyzed the development
of new drugs like the Drugs for Neglected Diseases Initiative, based in Geneva.
And new diagnostics for the Foundation for
Innovative New Diagnostics, also based here in Geneva.
What is the objective for this kind of initiative?
Is to develop a accurate diagnostic tools, effective treatments that are easy to use.
Easy to implement.
Which are affordable and deliverable to the people who need them.
So in other words, the objective is really to
improve the patient's access to quality care.
That's the overall objective of these PDPs.
Another recent development is the creation of large correlations of different actors.
That's a sort of typical approach that is the philosophy of global health to go and
really as a transnational and transectorial approach to health problems.
This coalition led to the London Declaration on the 13th of January 2012.
The pharmas, the PDPs, the public funders,
philanthropic funders present in this coalition.
And the objective that is led actually by the WHO road map
is to increase their commitment to fund research and
development for new diagnostic treatment or control tools.
But also to fund programs in countries to control or
eliminate some of these illnesses.
So I will end here.
I encourage to read this other report which is as I said
a Doctors Without Border report on some of the most neglected tropical diseases.
And see what are the remaining challenges for these illnesses.
I think hopefully I could transmit this
message that there are tools that are imperfected.
There are tools to control sometimes to limit some of these illnesses.
There is a medical approach for it but it will not be
sufficient in the long run to have these illnesses to
disappear from the surface of Earth will require much more.
And among them the alleviation of poverty,
which is of course is a clear transnational political issue.
Thank you very much for your attention.
[MUSIC]
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