COVID-19, Ebola, Malaria… Even as human activities are destroying biodiversity and increasing global temperatures, zoonoses are posing an increasing threat to humans. How does animal health affect us? Is it the poor cousin of development?

Disinfection session at a poultry farm in Haian, Jiangsu province (east China), in 2005, following the outbreak of a new bird flu epidemic. (Photo STR / AFP)
Disinfection session at a poultry farm in Haian, Jiangsu province (east China), in 2005, following the outbreak of a new bird flu epidemic. (Photo STR / AFP)

The COVID-19 pandemic offers a striking lesson that living systems, and more particularly animal health, have a direct impact on our lives. According to the US Centers for Disease Control and Prevention (CDC), three-fourths of new or emerging infectious diseases originate in animals.


Non-human, too human: the global health continuum

COVID-19, Ebola, and SARS have all received a great deal of attention in recent years, but their lowest common denominator is just starting to emerge: they are all zoonoses. Zoonoses are diseases transmitted from animals to humans: Ebola and SARS via bats, chikungunya via mosquitoes, and avian flu via birds and poultry. The recurrence of these diseases forces us to face the reality that our Cartesian heritage has allowed us to forget: we are a part of – and not the masters of – the natural world around us.



As such, we also play a key role in protecting animal health. In addition to zoonoses transmitted from animals to humans, there are also vector-borne diseases, in which living organisms (humans or animals) serve as a vector of transmission to humans and/or animals. One example is malaria, which infects humans through an animal vector. African Swine Fever is another example: it kills entire pig populations after being spread by humans (who are not infected).


Increasingly frequent zoonoses and vector-borne diseases

Zoonoses are clearly increasing in quantity and frequency in response to the global warming that is closely linked to an economic model based on unrestrained growth. In Alaska, several researchers have raised the alarm about the effect that temperature increases are having on the transmission of these diseases. Dr. Christian Chidiac, Head of the Infectious and Tropical Diseases Department at Lyon University Hospital, claims that climate change is already causing diseases to spread farther geographically.

The expansion of human territory, including through deforestation, leads to more interactions between humans and wild animals, increasing the likelihood of contamination. In the Democratic Republic of Congo, the destruction of forest cover has accelerated the spread of Ebola. “31% of epidemics such as the Ebola, Zika, and Nipah viruses are related to deforestation,” says economist Laurence Tubiana.

And with animals meant for human consumption, overcrowding and the extensive movement inherent in intensive animal farming also increases contamination. In 2016, a United Nations task force established a direct link between intensive livestock production and contamination with the H5N8 avian flu strain. Genetic uniformity among animals in this kind of industrial production is also a breeding ground for transmission.


Developing countries, the primary targets

These zoonoses and vector-borne diseases are increasingly frequent and mostly affect developing countries. This is the case with malaria in Africa. According to the World Health Organization (WHO), 94% of global malaria deaths occurred on the continent in 2018. These diseases are affecting countries with already fragile health systems, representing a significant step backward in their sustainable development. The United Nations recently revealed that in less than a year, COVID-19 has reversed decades of efforts to reduce poverty, improve education, and strengthen global health.



In addition to zoonoses, animal diseases that cannot be transmitted to humans, such as ovine rinderpest, can strongly impact a country’s economy as well as fostering inequality and gender and educational disparities, according to the World Organisation for Animal Health (OIE). Goat and sheep herds decimated by this disease impoverish small family farms in remote areas, where girls and women play a key role. Improving access to vaccines for these small-scale farms is critical to protecting these traditional and sustainable farming systems.


“One Health”: better addressing interactions between living organisms

Current events remind us that synergies between institutions such as the OIE, the WHO, and the Food and Agriculture Organization of the United Nations (FAO) are more essential than ever to promote a development model that takes interactions between living things into account. Last year, these organizations published a tripartite guide to addressing zoonoses, recommending a “One Health” approach that takes into account the animal-human-environment interface and promotes dialogue between disciplines.

In parallel, it has become increasingly clear that we must question our models of development. As Laurence Tubiana asks: “Has the extreme surge of globalization gone too far?”



The opinions expressed on this blog are those of the authors and do not necessarily reflect the official position of their institutions or of AFD.

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