The health of humans and animals belongs together

The COVID-19 pandemic reminded us of the devastating consequences that the transmission of pathogens from animals to humans can have. It’s not only the animals themselves that suffer from epidemics and diseases. According to the One Health approach, they need a good supply of medicines to protect their own health and that of humans.

1. Humans and animals live in symbiosis

Humans and animals share the same habitat. Gone are the days in Switzerland and in many other highly developed countries when farm animals were an established feature in households and secured their livelihood. But even today, many people spend their everyday lives in direct contact with or in close proximity to animals. It’s not just the farmers who rear several million cattle, pigs, sheep and goats in Switzerland alone, but also the people who have a passion for horse riding and all of those who nurture cats, dogs or other sorts of pets. Almost every second Swiss household is home to at least one pet. Zoos and game reserves also exert a great fascination for children and families in particular.

Humans share their natural habitat with pets, farm animals and wild animals. Animals are companions, and in many places they are used for their labour and to provide animal products. But this coexistence between humans and animals also has a drawback: diseases can be transmitted by close contact. The loss of natural habitats and unsuitable forms of animal husbandry favour the spread of pathogens. The Federal Food Safety and Veterinary Office also highlights climate change. This is causing infectious diseases that are transmitted by mosquitoes and ticks to spread further and further into the northern hemisphere. Protecting animal health therefore not only serves to maintain animal populations, but is also in the direct interests of human beings.

2. Animal diseases threaten humans

When animals fall ill, it is initially they themselves that are threatened. This particularly applies to highly infectious epidemics that sometimes kill entire herds of animals in a short period of time. Around one fifth of the losses in animal production worldwide are the result of epidemics. One well-known disease is foot-and-mouth disease, which affects cloven-hoofed animals. It is one of the most devastating viruses in agricultural livestock. The disease is highly contagious, and usually affects all the animals in a herd. The pathogen – a virus of the genus aphthovirus – sometimes remains infectious in stable muck, manure and slurry for several months. Another example is classical swine fever, which affects both pigs and wild boars. Both of these diseases have disappeared in Switzerland, but cause considerable harm worldwide.

Animal epidemics not only affect animals, but can also be dangerous for humans. For instance, the World Health Organization estimates that 59,000 people worldwide die of rabies each year, mostly in Asia and Africa. Diseases that are transmitted between humans and animals are classed as zoonotic diseases. One example is bird flu, which experts call highly pathogenic avian influenza (HPAI). In the winter of 2012/2013, it affected almost 50 million animals in over 2,400 farms across Europe, and these birds had to be killed. Infected wild animals such as black-headed gulls are frequently found in Switzerland. Transmission to domestic poultry and humans is suppressed by taking appropriate measures.

From the Radar Bulletin on highly pathogenic avian influenza (HPAI)

After a brief pause, the HPAI situation in Europe has once again deteriorated. Sporadic cases are regularly being reported in mammals, particularly carnivores. The risk for poultry over the next few months is difficult to predict. Experts still judge the risk of transmission to humans to be low. For several years now, programmes have been running in Switzerland to monitor swine influenza in humans (SIV programmes) and to monitor the health of wild animals (game health monitoring).

Source: FSVO – Radar Bulletin

3. Thinking of health as «One Health»

Scientific analyses show that five new infectious diseases are discovered in humans every year. Most diseases that occur for the first time or recur in humans originate from animals. Prominent examples include the most severe Ebola epidemic to date in West Africa from 2014 to 2016, the lung disease SARS, which was discovered 20 years ago, and the outbreak of BSE («mad cow disease») in the United Kingdom in the early 1990s. Consequently, collaboration between veterinary medicine, human medicine and environmental science is urgently needed.

The term «One Health» has been coined for this holistic approach. As part of this approach, experts from government agencies and the scientific community are working together to uncover connections and maintain the health of humans and animals in an intact ecosystem by means of suitable measures. At an international level, the World Health Organization (WHO), the Food and Agriculture Organization of the United Nations (FAO) and the World Organisation for Animal Health (WOAH) are collaborating jointly. In Switzerland, four of the federal agencies concerned and further partners founded the «One Health» platform in 2017. One historical forerunner is the US veterinary epidemiologist Calvin Schwabe, who in the 1960s worked towards close cooperation between animal and human medicine using the term «One Medicine».

Sixty per cent of pathogens in humans originate in animals.

Five new infectious diseases are discovered in humans each year.

Twenty per cent of the losses in animal production worldwide are the result of epidemics.

Source: European Commission, World Organisation for Animal Health

4. Drugs help to keep animals healthy too

«One Health» focuses on measures for monitoring health, as well as preventing and treating diseases and injuries. The use of medicinal active substances in animals plays an important role here. These substances include vaccines, antibiotics and other drugs for the prevention and treatment of infectious diseases, as well as drugs for treating parasite infections, inflammation and pain. The diverse nature of these substances is illustrated by what are known as the “big five” – loop diuretics, pimobendan, ACE inhibitors, spironolactone and amlodipine – that are used to treat heart conditions in dogs and cats. In Switzerland, livestock and domestic animals benefit from around 700 products.

Veterinary medicines are approved in the same way as human medicines, after they have been assessed by the Swiss regulatory authority Swissmedic. This applies to medicinal products prescribed by vets as well as those that are available over the counter. Veterinary drugs are often medicines that have previously been used in humans and have then been adapted for use in animals. This means animals too benefit from the time-consuming process of drug development, from basic research and preclinical research (laboratory and animal experiments) through to clinical trials in humans. The development process, which takes an average of 12 years for a new active substance, ensures that medicines are safe and effective. Animal experiments are vital for this purpose. The 3Rs principle (replace, reduce and refine) is applied to protect the animals. Animal experiments are only ethically justifiable if no other methods are available, and the number of animals and the stress to which they are subjected are kept to an absolute minimum.

5. Veterinary medicine benefits from innovative active substances

To keep animals healthy, medicines are also specially developed for them. One current example is an active substance for the oral treatment of feline infectious peritonitis (FIP), a deadly disease that affects cats. New medicines are constantly supplementing the range of active substances used for treating animals, and their areas of application are becoming ever more varied. They include preparations that have been available for several years now to treat allergies. During the COVID-19 pandemic, vaccines were developed for animals. They were used on mink farms to avoid mass culls and also to protect endangered zoo animals. The innovations that result from the development of new drugs therefore benefit both humans and animals.

The fact that veterinary medicine is constantly benefiting from innovative drugs is illustrated by the latest approvals granted by Swissmedic. Since last year, three veterinary drugs containing a newly developed active substance have become available. Two of these substances are used in dogs – to treat painful joint inflammation and epileptic fits. The third substance is intended for use in livestock. It is an antibiotic for cows suffering from a bacterial inflammation of the udder. Drugs developed specifically for animals are also inspected prior to approval in terms of their efficacy, safety and tolerability. One way in which this is done is by clinical animal studies where one group of animals is given the new substance and a control group is given a placebo. Thanks to these studies, side effects, interactions with other drugs and dosage guidelines can be determined.

Drug approval in human and animal medicine – 2012 to 2022

Veterinary drugs are subject to strict official approval, and their quality, efficacy and safety are assessed. The safety assessment includes safety in the target animals, for users and for the environment. In livestock, the safety of the foodstuffs produced is also assessed.

6. Outlook

Thanks to new drugs, medicine has achieved great progress for humans and animals. For instance, a large number of infectious diseases are now controllable or have even been completely eradicated thanks to systematic vaccination. These include distemper, parvovirus infections in dogs and cats, leptospirosis in dogs, rinderpest and equine influenza. Animal diseases that were previously fatal can now be treated. Examples in dogs include the common skin disease demodicosis and canine malaria (babesiosis). Another example is worm diseases in ruminants and horses.

Developing new medical active substances is a meticulously regulated process that takes many years. Animal experimentation forms a vital part of this process. It ensures the development of new drugs that maintain human health, and in many cases also benefit pets, livestock and wild animals. Opposition to animal experimentation hampers medical progress, to the detriment of humans and animals. Sound animal health is essential, and humans benefit from this in two ways – fewer diseases are transmitted from animals to humans, and animal foodstuffs such as milk, meat, eggs and honey are also made safer.