Nearly 75% of emerging infectious diseases are transmitted from animals to humans. This observation prompted the creation of One Health, a collaborative, multidisciplinary initiative to fight health threats more effectively.
In the spring of 2021, French officials recommended that people living in the Doubs and Jura regions near forests wear a mask. Not because of Covid-19, but because several people had been hospitalised for a Puumala virus infection, a species of the hantavirus genus (see inset) transmitted by rodents such as field mice or voles through their excrement.
“This virus causes a haemorrhagic fever with renal syndrome, with symptoms similar to those of the flu (fever, headache, muscle pain),” says Sylvia Rothenberger, principal investigator of a research group focusing on hantaviruses at the Microbiology Institute at Lausanne University Hospital (CHUV). “Most cases are harmless, but the disease can sometimes cause serious kidney problems in some patients and even death.”
The Puumala virus that is worrying health officials so much in neighbouring France is a zoonotic disease. This is a group of infectious diseases that pass naturally from animals to humans. They account for 60% of infectious diseases that affect humans. It is estimated that three-quarters of all emerging infectious diseases are of zoonotic origin.
Zoonoses account for 60% of infectious diseases that affect humans.
Deforestation, intensive farming and breeding practices, and increased resistance to antimicrobial agents are factors contributing to the emergence of these diseases, which include Ebola, Middle East respiratory syndrome (MERS), sudden acute respiratory syndrome (SARS), Zika and Covid-19.
To respond to these new diseases, the United Nations established the One Health initiative in the early 2000s. The objective consists in measuring the inter-connections between the health of people, animals and the environment. It also brings together different disciplines to address all health threats and prevent potential disruption in food systems.
The One Health movement seems to have regained strength since the beginning of the health crisis that has disrupted the world over the past year.
“One Health enables us to counter the shift towards hyperspecialisation taking place in our professions,” says researcher Sylvia Rothenberger. “For example, similar virus structures can be found in plants, insects and rodents. New collaborations can be developed between doctors focusing on human health and field biologists.”
This idea has long been at odds with a more commercial approach to medicine. But the One Health movement seems to have regained strength since the beginning of the health crisis that has disrupted the world over the past year. In late May, a group of international organisations announced the launch of a new One Health High-Level Expert Panel to improve understanding of how diseases that could trigger pandemics emerge and spread.
“The High-Level Expert Panel is a much-needed initiative to transform One Health from a concept to concrete policies that safeguard the health of the world’s people,” Tedros Adhanom Ghebreyesus, Director-General of the World Health Organization, said. “The close links between human, animal and environmental health demand close collaboration, communication and coordination between the relevant sectors.” /
Hantaviruses are found in small mammals such as mice or voles. Infection can be caused by bites, direct contact with the animals or inhaling contaminated dust. Since 2000, about 3,000 cases have been reported in Europe every year, but Switzerland has thus far been spared for the most part. As no vaccine exists for these viruses, people should avoid contact with rodents and their droppings in risk areas and refrain from handling wood or soil.
Brucellosis
This disease is spread by domestic livestock and raw dairy products from infected animals. Symptoms include fever and possibly chronic joint pain or neurological complications.
Salmonella
This bacterial infection causes diarrhoea, fever and abdominal cramps after ingesting contaminated food or water.
Rabies
This highly contagious disease is transmitted to humans through bites of carnivorous animals. It is fatal in almost all cases and causes 59,000 human deaths worldwide every year, according to the World Health Organization.
