Well, you have had the previous sequence on climate change and health.
I would like to focus on the impact of climate change on infectious disease.
It is very debated.
There is no consensus on many things
regarding the impact of climate change and infectious disease,
for instance, because there are some discrepancies.
We can say of course that the global warming is good
for the proliferation of mosquitoes and so,
it may be prone to increase the risk of malaria for instance.
But the point is that malaria is decreasing dramatically for decades now,
thanks to all the control measures and all the bed nets and
all the anti-mosquitoes actions
and global determinations of eradicating malaria if possible.
There is probably many other determinants and
not only climate regarding the evolutions of infectious disease.
But I would like to focus on a particular point which is El Nino,
La Nina effect on the climate on infectious disease.
El Nino and La Nina are oscillations in South Pacific,
meaning that there is difference in the temperature of the ocean which is
the largest ocean in the world which has a lot of impacts on the climate in the world.
El Nino and La Nina are not directly due to the climate change,
it occurred much before the global warming appears.
So, El Nino and La Nina events are regular oscillations which comes and wane,
but due to the climate change,
climatologist said that El Nino and La Nina are more intense and more frequent.
What are the impact of El Nino and La Nina on infectious disease?
It is now more clear.
For instance, in the Horn of Africa,
it's very far from the Pacific Ocean.
In the Horn of Africa,
when there is an El Nino event,
the remote sensing data,
meaning the data captured by satellites,
can really observe that there are floating,
there are a lot of rain in the Horn of Africa which are usually desertic and very dry.
But when there is an El Nino event,
the Horn of Africa is prone to flooding and is prone to
very high risk of specific disease such as the Rift Valley Fever,
Malaria and the cholera.
The Rift Valley Fever to take this example is a mosquito-borne disease.
So, this mosquito, when it is floating,
it's developing much more quickly and the risk of Rift Valley Fever outbreak is major.
What is Rift Valley Fever as a disease?
It is a very severe disease,
probably more severe than Ebola.
So, we are scared by Ebola,
we should be scared by Rift Valley Fever in the Horn of Africa,
particularly because it attacks both the cattle and the human.
So, animals and humans are at severe risk with the Rift Valley Fever infection.
So, when there is an El Nino event which is the case in 2016,
to tell, there is an El Nino even currently in 2016,
there is a major risk of Rift Valley Fever in this part of the world.
So, if we have some aid and some preventive measures to focus this knowledge of El Nino,
La Nina, it's very useful to help preventing this disease.
But what we have to say is,
if El Nino and La Nina becomes more frequent and more
severe due to the global change and the climate change,
we may foresee that we will have a lot of these kind of events in the future.
I only take the example of the Horn of Africa,
but in several parts of the world,
there are some impact of
El Nino and La Nina which are related to other disease and other infections.
For instance, when there is a La Nina event,
there is a huge risk of Chikungunya,
dengue or yellow fever disease in this part of the world,
the Horn of Africa or the Indian Ocean.
We have experienced a huge epidemic of Chikungunya in 2006 in the Indian Ocean,
but also in Kenya and in most of the islands of the Indian Ocean,
and that was just after a La Nina event.
Another point regarding La Nina event is as it has been clearly shown that La Nina
is associated with huge epidemics of influenza in the north country.
So, it's not only the Horn of Africa which is concerned by La Nina and El Nino,
it's also the global north,
the USA and Europe experience more severe and more intense
influenza epidemics and also pandemics when La Nina events came.
Meaning that La Nina is also more frequent and more intense due to the climate change,
we may expect that our influenza outbreaks will be more severe,
more frequent and more intense due to the global climate change.
That was what I wanted to say regarding
the fact that there is a lot of disease which are related to,
I would say regular oscillations,
but these regular oscillations, El Nino,
La Nina or South Pacific ocean oscillations is
also massively impacted by the climate change today.
Rafael Ruiz De CastañedaInstitute of Global Health - Faculty of Medicine
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)
