Charlotte Foster
Diseases that are transmitted from animals to humans are on the rise worldwide. Some of these are based on horses. In our latitudes, this rarely happens. Caution and, above all, good hygiene around the horse are still appropriate.
It is suspected that a half-cooked bat at a market in China was the trigger for the corona pandemic. What is certain is that new pathogens are increasingly managing to cross the species barrier from animals to humans. In the last few decades, there has been a drastic increase in new infectious diseases in humans. Around 75 percent of the previously unknown pathogens come from the animal kingdom. And the UN recently warned of a further increase in the so-called zoonoses, which are favored by increasing mobility and urbanization as well as climate change.
Around 200 diseases are currently known worldwide that occur in both animals and humans and can be transmitted in both directions. The actual pathogens can be viruses, bacteria, fungi, protozoa, worms, or arthropods such as arachnids and insects. The carriers of these diseases are often domesticated four-legged friends such as livestock or pets. Zoonoses are not uncommon in Switzerland either: the statistics record over 10,000 people a year who contract an animal-borne disease – and the trend is rising.
If you like to cuddle your horse, kiss it on the nose, clean its coat, muck out the stable and wipe the feeding trough clean, you have to reckon with coming into contact with pathogens. There are around two dozen diseases that can be transmitted from horses to humans. Some are harmless, others lead to serious illnesses. Some zoonoses occur worldwide, others only in certain countries.
Important tetanus vaccination
“Rabies, for example, used to be an issue here too. But Switzerland has been officially rabies-free since 1999,” says Franziska Remy-Wohlfender, an equine veterinarian from the canton of Bern and co-responsible for Equinella, the reporting and information platform for equine infectious diseases. Thanks to our good standard of hygiene and medical progress, many zoonoses in Switzerland have lost their terror. Dangerous diseases such as anthrax or glanders, which continue to pose a threat to human and animal life in Asia, Africa, and South America, are only found in exceptional cases in Europe.
Lockjaw (tetanus) has become rare thanks to vaccination. Horses – but also people! – are very susceptible to this severe acute wound infection disease, which is triggered by the toxin of the tetanus bacteria. Once the four-legged friend has become infected, his chances of survival are low. The tetanus vaccination reliably protects humans and animals. Practical combination preparations are available to the veterinarian for horses to be vaccinated against influenza at the same time.
The risk of being infected by a horse with a life-threatening disease in our part of the world is manageable. Dogs and cats represent the greater source of danger in this respect because they live closer together with humans than horses. Nevertheless, horse owners and riders cannot breathe a sigh of relief, because in our daily dealings with the horse some diseases are relevant to us, which may not be fatal, but are still unpleasant. “The first thing that comes to mind is dermatomycosis, which is relatively common,” explains Remy-Wohlfender. Infection caused by fungi is one of the most common skin diseases in horses.
Fungal spores are found in the soil, and horses become infected when rolling or scratching in the soil, from other horses, or shared saddlery and grooming equipment. The fungus can spread to humans when touching affected horses or contaminated objects. In horses, skin fungus presents as crusty, dry patches of skin with hair loss and itchy, circular lesions. Humans often develop a similar scaly, red, circular rash. Skin fungi often heal on their own, so medical shampoos or antifungal washing solutions from the veterinarian or pharmacy can help to relieve the itching.
Antibiotics only in emergencies
Dermatophilosis is transmitted by bacteria, which usually enter the horse’s body through an open wound such as a cut or an insect bite. Also known as dirt eczema or rain mange, it often occurs in horses that have been exposed to a lot of moisture for a long time. It causes painful lesions on the back, mouth, and legs that form dry, scaly crusts. If the bacteria spread to humans, skin changes appear on the hands and arms. If necessary, it is treated with antibiotics.
However, its use should be well dosed and considered, because excessive use of antibiotics has led to another problem for horses and humans: multi-resistant germs. “Both in human and veterinary medicine, an increase in these multi-resistant bacteria has been registered for years,” says Franziska Remy-Wolfenden. Particularly sensitive are the multi-resistant Staphylococcus aureus (MRSA) and bacteria whose enzymes impair the effectiveness of antibiotics (ESBL), which can be transmitted from horses to humans and vice versa. Staph is normal skin dwellers that are usually harmless. “However, they can cause wound and skin infections in people and animals with a poorly functioning immune system,” explains equine veterinarian Remy-Wolfenden.
Normally, these diseases can be treated well with antibiotics, provided they are not resistant to germs. Then wound care becomes a lot more complex, there is a risk of hearing disorders and, in the worst case, blood poisoning, which can be fatal.
Corona has sensitized people
Over the past two years, humanity has learned what measures can be taken to contain a virus. “Since Corona, people have been more sensitized to hygiene,” Remy-Wohlfender noted. Good hygiene management in the stable at home and abroad, at courses or tournaments, ensures that the horse is in good health and reduces pathogenic pathogens.
In this way, infections from horse to horse or from horse to person can be avoided. “You shouldn’t eat in the stable and wash your hands thoroughly before and after every visit to the horse,” advises the expert. When dealing with sick or injured horses, especially when treating wounds, she recommends disinfecting your hands and wearing disposable gloves.