Infectious diseases, the main causes of human mortality according to the WHO, have always been a particular concern for society.
In a context of global change, the fight against infectious diseases remains a major challenge for the future and especially for Dominique Pontier and François-Loïc Cosset, researchers at the Université de Lyon. Their research has been published for the Health Innovation forum that took place on March 13, at ENS de Lyon.
Most human pathogens have a "zoonotic" origin, i.e. coming from the animal world and are transmitted by direct or indirect contact, via various species, including hematophagous arthropods (mosquitoes, ticks, etc.), micromammals, bats, etc.
Whether it be the recent epidemics of the Zika and Nipah viruses, carried by mosquitoes and bats, or the (re) emergence of previous threats such as hemorrhagic fever viruses (Ebola, Lassa, Crimean-Congo fevers), everything indicates that infectious (re) emerging diseases will remain a major concern for human and veterinary health for a long time.
Therefore, it is not surprising that zoonoses currently represent the most important infectious danger to humans, posing major public health problems and crucial issues for the future.
Climate change, migratory flows and ecosystem transformation
We must remind ourselves that human activity greatly increases the frequency and severity of infectious (re) emerging diseases as it disrupts host, vector and pathogen interactions at different scales.
Many factors, such as climate change, migratory flows and, of course, ecosystem transformation, explain that the transmission dynamics of infectious agents are constantly evolving; they are now propagating faster and further, and they are (re) emerging more often than before.
Increased infectious risk
Since the Seventies, new emerging diseases have been identified at an unprecedented rate of at least one per year, with 40 unknown infectious diseases only a generation ago!
Even if historically, the countries of the tropics and subtropics have experienced the highest rates of infectious diseases, it now seems clear that most countries are permanently exposed to infectious risk.
The intensification of trade, agriculture and mobility in a warmer, more populous, multi-ethnic and socially unequal Europe, with an ageing population, offer a myriad of opportunities to promote the spread of pathogens.
Taking into account the complexity of human-animal relations
Although in principle, the reduction of contact with zoonotic reservoirs or vectors can potentially limit epidemic episodes, there are so many possible scenarios that it is difficult to say if such a strategy would really be effective. This stresses the importance of taking into account the complexity, specificity and ecology of human-animal relations on a local level.
The development of increasingly accurate scientific and medical knowledge has led to solutions being put forward in the field of infectious diseases and their control, for example in the field of diagnosis, we are focusing on prevention or treatment, as well as the management of patients with infectious diseases.
The “One Health” approach
However, we can see the limits to these solutions, as generally speaking these aspects are largely focused on human health. However, recent advances in certain critical human diseases, such as Ebola fever, demonstrate that it would be possible to effectively counteract these diseases by considering the relationship between hosts and pathogens as one.
The belief is that, only an interdisciplinary approach will address the urgent and growing challenges associated, for example, with antimicrobial resistance and, ultimately, the definition of sustainable human and animal health policies.
This integrated approach, called "One Health", must combine levels of complementary studies to identify key processes and mechanisms, by gathering knowledge and skills from broad disciplinary fields.
Source: Pour une approche globale de la lutte contre les maladies infectieuses, La Tribune, March 6, 2019.