When your horse is ill, you may be so concerned about trying to get them better that you don’t think about your own health. However, there are a number of diseases that can be spread from horses to humans. These are known as zoonotic diseases and they can be quite dangerous for human health.
Ringworm is a fungal disease that causes lesions on the skin. It is very contagious, being spread easily through direct contact or by contaminated equipment. In humans, the lesions usually look like red rings. But in horses, they often appear as round, dry, crusty patches with hair loss.
The spores of the fungus can survive in the environment for several months, with the incubation period being between one and three weeks. The disease is generally self-limiting, meaning that it goes away on its own after a few months. However, anti-fungal treatment can be used to speed up the healing process. To prevent the spread of ringworm, hands should always be washed after touching animals, all equipment should be cleaned and disinfected regularly and any new or affected horses should be isolated from others.
Salmonella is a common cause of diarrhoea in the UK, with the bacteria being found in the intestines of many wild and domestic animals. It can produce severe diarrhoea and colic signs in horses. Although it is usually self-limiting, supportive care with intravenous fluids may be required. To prevent the spread of salmonella, always wash your hands before eating and make sure stables and food and water buckets are disinfected between horses.
Streptococcus zooepidemicus is a bacteria that is often found on the oral and respiratory membranes of healthy horses. But it has been associated with infection of the skin, respiratory tract and reproductive tract in horses. It is spread by direct contact and rarely causes disease in humans.
In humans, the symptoms of the disease are usually flu-like but can progress to more severe disease such as meningitis and heart disease.
Although it’s uncommon, the bacterium that causes rain scald (Dermatophilus congolensis) has been known to jump onto humans, causing lesions on the hands and arms. Fortunately, we tend to keep our skin dry and so it rarely gets a foothold.
There are also a range of more exotic – and more worrying – diseases that horses can carry and pass on to us.
Glanders is caused by a bacterium, which has been eradicated from Europe through tight import control measures. However, the disease is often reported in other countries around the world. It is life-threatening, causing nodules and ulcerations in the respiratory tract.
Although there isn’t a vaccination available, the disease in humans can be treated with antibiotics if they are started soon enough. The disease is usually spread through ingestion of contaminated food or water, using contaminated equipment, or by droplets spread from coughing and sneezing. Precautionary hygiene measures should be taken if a horse is suspected of having the disease. And humans should avoid contacting infected animals. When importing a horse into a glanders-free country such as the UK from a higher-risk area, samples must be collected prior to travel to ensure that the disease will not be brought into the country.
Although not present in the United Kingdom, Hendra is a devastating disease that can be fatal in both horses and humans. The virus has been found in fruit bats and has caused a number of outbreaks in Australia. In humans, the signs can range from mild flu-like symptoms to severe respiratory and neurological disease. There is no specific treatment for Hendra. However there are vaccinations available for horses which reduces the spread of the disease to humans.
Are you safe if your horse is poorly? Probably, as the risk is pretty low but it’s worth just taking a few precautions. And if in doubt, ask your vet if the disease might be zoonotic!