We all love sharing things with our pets; cuddles, games, and our beds – even though it’s often not by choice – but is it possible to unintentionally share the less desirable things such as disease? The simple answer is yes, and there are numerous diseases that can be transmitted via a process called reverse zoonosis.
Zoonosis involves the transmission infectious diseases from animals to humans, and reverse zoonosis refers to transmission from humans to animals. Some modern diseases such as Ebola and HIV were zoonotic diseases that transferred to humans, and in the case of HIV it has now evolved into a human-only disease.
Avian flu and swine flu have highlighted the seriousness of zoonosis, and even though it is much less common, we can in fact make animals sick. Transfer of disease from humans to animals is much less studied than animals-to-humans, and it is not even clear whether our pets can catch the common cold from us; Some experts believe that whilst dogs can't catch human colds, cats can, even though the chances are slim.
Common Colds and the Flu
Humans and animals can both develop symptoms typically associated with colds, however the likelihood of a person passing a cold to a dog is very low if it is indeed possible. Colds in both dogs and people generally resolve on their own, but if symptoms don’t improve seeking doctor or veterinary assistance is recommended.
It has been long believed that flu can’t be transmitted between humans and animals but the virus’s adaptability may mean that some strains can in fact be transmitted by humans to animals, including dogs. Whilst the risk is extremely low you should play it safe and steer clear of your pets while suffering a cold or flu.
While the jury is still out over the familiar and annoying cold, what about some of the more serious illnesses? Which of those can our pets potentially catch from us?
Humans and animals can infect each other with ringworm
Dermatophytosis, commonly known as ringworm, is an infection of the skin that affects both animals and humans. Its name is misleading because ringworm is caused by a fungus rather than a worm. Ringworm usually causes round patches of hair loss in dogs that are sometimes itchy. In humans, ringworm causes an itchy, round rash. It can be transmitted through direct contact with infected animals or humans, and can also be transmitted via contaminated objects such as towels and brushes.
Topical antifungal medications are used to treat ringworm, and sometimes it’s also treated systemically with an oral medication. Dips and shampoos are used to minimise the spread of spores which can lead to further infection. People diagnosed with ringworm should keep the affected areas covered to avoid transmitting the condition to other people and animals.
Can my dog catch mumps from me?
If it’s possible for pets to catch the flu from us, then how about mumps? The symptoms of this highly contagious virus include headache, muscle pain, fatigue, and fever. The disease normally leads to painful swelling of the salivary glands on each side of the face. It can affect people of any age despite being associated mostly with children, dogs can become sick if exposed to someone who is infected.
The symptoms in dogs are similar to those in humans. Most animals will recover in one-to-two weeks, but there is no cure for the disease. Symptomatic treatment may be recommended by your vet in order to increase your pet’s comfort while they’re getting over it. The risk of your dog catching mumps from you is low, but it’s best to keep pets away from infected people regardless.
What about the world’s most common water-borne disease, salmonella?
Salmonella can also be passed between humans and animals and it causes diarrhoea, nausea, vomiting, headaches, abdominal cramps and fever. It is often associated with food poisoning, and the elderly and children are more at risk of complications. The chances of someone infected with salmonella making a dog sick are slim because dogs have an increased resistance to it.
Avoiding contact with pets if you’re infected with salmonella is recommended nonetheless, and infected people should be particularly careful about washing their hands after using the toilet. Keep animals away from food that could be harbouring it, and keep dogs away from garbage bins containing discarded food waste if the disease is food-borne.
Giardia can be passed between people and animals
Giardiasis, or giardia infection of the bowel, is a common waterborne infection and causes diarrhoea, abdominal pain, and weight loss. It can cause long-lasting symptoms and serious illness, particularly in children. Giardia is caused when infection with the parasite Giardia duodenalis occurs. The parasite can be caught by coming into contact with contaminated water, food, and faeces, and it can also be transmitted between animals and humans.
Giardia appears in dogs, cats, and even exotic animals. The most common place to find it is in water, and as well as in drinking water it can be found in, lake, swimming pool, and spa water.
Methicillin-Resistant Staphylococcus Aureus (MRSA) is a bacterium that can be contracted by the general community but which is particularly prevalent in hospitals and other health care facilities where patients’ immune systems are already compromised. The bacteria have developed resistance to many antibiotics and usually cause surgical site infections, skin infections, and sepsis.
The chances of healthcare workers passing this infection to their pets is low. Animals would probably need to be actively infected from infected persons in order to contract it.
Lyme borreliosis, or Lyme disease, is a bacterial disease spread by ticks. The initial symptom is usually a pink or red rash. It starts as a small spot that gradually spreads with a characteristic bulls-eye appearance. This occurs up to a month after being bitten by an infected tick, however not everyone with Lyme disease gets a rash. Headaches, fever, and fatigue are usually symptomatic of the disease. Left untreated, the disease can spread and can cause infection in the brain and heart. The disease can also cause long-term neurological symptoms and joint pain.
The ticks that pass on the infection are commonly found in parts of Asia, Europe and North America. Related ticks can be found in Australia but these have not been identified as carrying Lyme disease - Borrelia bacteria. Even with medical treatment, Lyme disease can cause people infected with it to suffer debilitating symptoms for six months and more.
It can also be a serious disease in dogs, and in addition to the symptoms experienced by humans, dogs can also experience kidney issues and lameness caused by inflammation of the joints. Only ticks are the conduit for Lyme disease, and the disease therefore can’t be transmitted from human to human, or human to animal. Acquiring Lyme disease from ticks in Australia cannot be ruled out, but there is little evidence of it. The greater risk exists for overseas travellers.
Cleanliness is next to petliness
Ok, so “petliness” isn’t a real word, but if it was, it would refer to the quality of being a committed and responsible pet owner. While the chances of passing most diseases to our pet are negligible, simple precautions should be taken. Washing hands is something that should be practiced routinely regardless of whether we’re handling pets or not. Preventing animals from licking our faces is another safety measure that all pet owners should maintain.
The risks of transmission of disease between animals and humans is increased for people with compromised immune systems, and care needs to be taken to avoid cross-infection. If you have any questions or concerns, raise them with your doctor or your veterinarian. The team at Vets4Pets is always available to help answer your questions.