Think Twice Before Petting Your Dog If You Have Any Of These Diseases

Petting a dog can have unexpected health side effects, such as reducing stress, releasing endorphins, and lowering blood pressure. These bonding moments make for cherished memories, and being told you can't do simple actions like giving your pup some scratches or belly rubs can be upsetting. Yet, there are certain diseases that people can get that they can transmit to their dogs through reverse zoonosis.

Zoonosis has become widely known, with the transfer of diseases from animals to people periodically making headline news. Reverse zoonosis, the transfer of diseases from people to animals, is less reported or discussed. However, a June 2023 study by Benjamin Anderson, Ph.D., of the Department of Environmental and Global Health, and his team concluded that the prevalence of reverse zoonosis could be higher than initially thought.

When speaking with the Emerging Pathogens Institute of Florida in 2024, Anderson noted, "When you see a human in the clinic, you can ask questions like whether they were around any animals, or if any of their pets were sick. But when you get an animal that's sick, you may not always be able to get that kind of information to link it back to a human case." With this in mind, pet parents should always be cautious when they are ill around their pets, particularly regarding the following specific illnesses.

More commonly known as the flu, Influenza is a contagious respiratory disease that affects the nasal passages, throat, and lungs. People with the flu are most contagious within the first three days of infection, though healthy adults may start the spread before they experience symptoms themselves. The disease spreads through tiny droplets when infected people talk, sneeze, or cough; in some cases, it can also be transmitted by touching contaminated surfaces.

Dogs can also get the flu, showing symptoms similar to those of their human counterparts, such as coughing, sneezing, breathing difficulties, and lethargy. The disease is highly contagious and non-curable (a dog has to be quarantined and wait it out). Preventive measures, such as the DA2PP vaccine, are available. While the chances of zoonosis spreading influenza are low, the ability for the disease to mutate to spread still poses a threat to transfer from owner to pet. Washing your hands and staying away when sick can help.

COVID-19, or the most well-known coronavirus, was one of the most significant global challenges of the 21st century. It led to lockdowns and reshaped numerous jobs and daily activities. Depending on the variant and the individual, coronavirus presents a wide range of symptoms, from headaches to loss of taste. The virus spreads through droplets released when the infected breathes, coughs, or sneezes; spreading through contaminated surfaces is possible but low.

Canine coronavirus comes in two varieties: enteric, which infects the gastrointestinal tracts and damages cells, and respiratory, which infects the lungs and causes breathing issues. Symptoms vary depending on the strain, and respiratory coronavirus often appears in addition to other conditions like distemper or influenza. There is no specific treatment for canine coronavirus; a vet will provide needed care and medicine to help manage symptoms. The virus is highly contagious between dogs, spreading through air or contaminated surfaces. Like influenza, the coronavirus's ability to mutate increases the likelihood of transfer from owner to pet.

Despite its name, ringworm is not spread by an actual worm; instead, it is a circular-shaped fungal infection that is red and itchy. Ringworm is a prevalent affliction, affecting 20% to 25% of the world's population at any given time. While the infection has different names depending on where it occurs — athlete's foot, jock itch, scalp ringworm — when appearing on the hands, known as tinea capitis, it can be exceptionally infectious to a canine through petting them.

The symptoms of ringworms in dogs are similar to those of their human counterparts, including inflamed or dark circular patches on the skin. In dogs, hair loss in these spots is also common, and it can also appear as brittle or misshapen nails. At the same time, some dogs can be silent carriers of ringworm. Ringworm can be challenging to treat due to its persistent spreading, requiring quarantine with topical or oral medication and follow-up vet visits. While ringworm may seem mild, with the amount of work and vet bills needed to address the fungal infection, an owner will want to refrain from petting their dog when affected.

Better known as salmonella poisoning, Salmonellosis is a bacterial infection caused by eating undercooked food such as eggs, poultry, meat, and produce. Symptoms primarily affect the bowels and stomach, including cramps, vomiting, and diarrhea, but fever and headaches can occur. In most cases, symptoms will only last up to a week, but more severe reactions can appear in young children, older adults, or those with compromised immune systems.

Salmonella bacteria is more likely to be passed from dog to owner. A 2017 study by the American Society for Microbiology showed that of the dogs with salmonella present, only 55% exhibited the common symptom of diarrhea, reflecting an asymptomatic spread of the infection. Moreover, dogs are more likely to eat contaminated food they find outside and won't hesitate to gobble up uncooked meat that is accidentally dropped. Still, salmonella poisoning can be passed from owner to pet, and a pet with a compromised immune system or on antibiotics can be more susceptible to severe reactions, like fever, shock, or blood loss. 

Methicillin-resistant Staphylococcus aureus, usually shortened to MRSA, is a staph infection that appears as a large, red bump full of pus. The painful-to-the-touch infection can also cause other symptoms, such as fever, chest pain, or shortness of breath. If left untreated, it can lead to pneumonia in the lungs and damage organs like the kidneys, spleen, or heart. Whereas other staph infections can be treated with antibiotics, MRSA poses a unique challenge as it resists multiple medicines.

The symptoms of MRSA in dogs are similar, including fever and skin abscesses. However, if the condition does not clear by itself after a week or two, it can be treated with antibiotics. To stop the spread of MRSA, an owner must treat and disinfect wounds according to the instructions of a veterinarian. This is essential as the disease can be transferred from pet to pet parent as well as vice versa. If suffering from MRSA or any other diseases susceptible to reverse zoonosis, caretakers should exercise caution in how they interact with their dogs to avoid making them sick. By taking care of yourself first, you can avoid heartache and financial strain — be sure to wash your hands, take precautions, and then enjoy cuddling your pup again once you're feeling better.

Always consult your veterinarian before making changes to your pet's diet, exercise, or care. To find an accredited veterinarian in your area, you can search the American Animal Hospital Association's online database.