Paris France.- monkey pox, SARS (Severe Acute Respiratory Syndrome), ROM (Middle East Respiratory Syndrome), ebola, bird flu, zika, HIV and possibly the covid-19… Zoonoses, diseases transmitted by animals to humans, have multiplied in recent years, raising fears of new pandemics.
What is a zoonosis?
Zoonoses are diseases either infections animal-borne vertebrates to humans and vice versa. The pathogens They may be bacteria, virus either parasites.
These diseases are transmitted either by direct contact between humans and animals, through food or of a vectoras insectsspiders or mites.
According to World Organization for Animal Health60 percent of human infectious diseases are zoonotic.
What kind of diseases is it?
The term “zoonosis“regroups a wide variety of diseases that can affect the digestive system, such as salmonellosis; the respiratory, like the bird flu and swine flu, or the covid; or the nervous system, such as Rage.
The severity of these diseases in humans varies; the causative pathogen can be more or less virulent, but it also depends on the infected person, who can be particularly sensitive.
What animals are involved?
The bats They act as a reservoir for many viruses that affect humans. Some have been known for a long time, such as rabies, but many have appeared in recent decades, such as ebolahe coronavirus SARS or the Nipah virus, which was located in Asia in 1998. It is being studied whether the covid-19 had a similar origin.
Badgers, ferrets, minks and weasels are also often implicated in viral zoonoses, mainly those caused by coronaviruses.
Other mammals (cattle, pigs, dogsfoxes, camels, rodents) can also be the intermediate host.
All the viruses responsible for the large pandemics of flu they had an avian origin, direct or indirect. Also insects such as ticks are vectors of many viral diseases.
Why has the frequency of zoonoses increased?
Zoonoses appeared thousands of years ago, but have multiplied in the last two or three decades. Greater travel facilities allow them to spread more quickly.
The humansBy expanding their presence over ever larger areas of the planet, they contribute to disrupting the ecosystem and promoting the transmission of viruses.
The intensification of cattle raising industrial use increases the risk of spreading pathogens between animals.
The wildlife trade is another factor that enhances human exposure to the microbes they may carry.
Deforestation increases the risk of contact between wildlife, domestic animals and human populations.
Should we fear another pandemic?
He climate change it could push many animals to flee their ecosystems towards more habitable lands, according to a study published in Nature in 2022.
And by mixing more, the species will transmit more of their viruses, which will favor the appearance of new diseases potentially transmissible to humans.
The pandemics “They will emerge more frequently, they will spread faster, they will kill more people,” the UN Panel of Experts on Biodiversity (IPBES) warned in October 2020.
The reservoir is immense: according to estimates published in the journal Science in 2018, there are 1.7 million unknown viruses in mammals and birds, and between 540,000 and 850,000 of them “would have the capacity to infect humans.”
But above all, the expansion of human activities and increased interactions with wildlife multiply the risk that viruses capable of infecting humans will “find” their host.
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