He asserts that zoonoses have multiplied in recent years. Vertebrate animals transmit diseases that can even become specifically human, like Covid-19. According to the World Organization for Animal Health, approximately 60% of emerging diseases are of zoonotic origin.
Farming, travel and deforestation in question
Several elements lead to this phenomenon, in particular “the intensification of travel, which allows (diseases) to spread more quickly and in an uncontrolled manner”, underlined Marc Eloit, head of the Discovery of pathogens laboratory at the Institut Pasteur. By occupying increasingly large areas of the globe, humans contribute to disrupting the ecosystem and promoting the transmission of viruses. The intensification of factory farming also increases the risk of the spread of pathogens between animals. The trade in wild animals increases human exposure to the microbes they may carry.
Deforestation increases the risk of contact between wildlife, domestic animals and human populations. “When we deforest, we reduce biodiversity. We are losing animals that naturally regulate viruses, which allows them to spread more easily, ”explained Benjamin Roche, biologist at the Research Institute for Development (IRD), specialist in zoonoses.
The threat of global warming
Climate change will also push many animals to flee their ecosystems for more livable lands, warned a study published in Nature at the end of April. However, by mixing more, the species will transmit more of their viruses, which will promote the emergence of new diseases potentially transmissible to humans.
The study draws a future “network” of viruses jumping from species to species, and growing as the planet warms. “A whole line of new, potentially dangerous diseases is likely to emerge. We will have to be ready, ”warned Eric Fèvre, professor specializing in veterinary infectious diseases at the University of Liverpool and the International Livestock Research Institute.
The main and recent diseases caused by zoonoses
The beginning of the 21st century was marked by several epidemics of emerging viruses linked to zoonoses. Caused by a new coronavirus, Sars-CoV-2 (whose origin remains uncertain), Covid-19 emerged at the end of 2019 in China before spreading around the world, killing more than 6.2 million people. dead according to a report, at the end of May 2022, from the American university Johns Hopkins.
Similar and originating from China in 2002, the Severe Acute Respiratory Syndrome (SARS) virus was transmitted from bats to humans via civets, a wild mammal sold at the time on Chinese markets for his meat. Also in the realm of coronaviruses and first detected in 2012 in Saudi Arabia, Middle East Respiratory Syndrome (MERS) is a viral respiratory disease caused by a novel coronavirus transmitted by camels. It caused the death of a third of the infected cases, with 850 victims in total.
Still linked to bats, and first identified in 1976 in the Democratic Republic of Congo, the Ebola virus has sparked a series of epidemics in the 21st century in Africa that have taken the lives of more than 15,000 people in total. . From the same family, the Marburg virus – a serious disease that causes severe hemorrhagic fever – emerged in 1967 in Germany and Yugoslavia following work on green monkeys. It causes the death of approximately 50% of those infected.