#1 – Giardia

Giardia is a Protozoal parasites often from contaminated drinking water. Infected dogs can serve as a source for humans, as can infected humans serve as a source for their dogs. Although very difficult to be sure that your dog never drinks from puddles that could contain the fecal matter of infected wildlife, you can treat and filter water when you are hiking and camping to protect yourself and try to encourage your dog to choose treated water when thirsty.

Symptoms in pets: Diarrhea

Symptoms in humans: Diarrhea


#2 – Roundworm

Roundworm is technically zoonotic and can cause horrific skin and ocular lesions in affected humans. In our culture with excellent hygiene and careful parasite control for our dogs, we don’t hear of these cases often. The incidence is thought to be higher in urban areas where population density puts children more likely to come in contact with the feces of infected pets. There are other intestinal parasites that can cause human disease as well. Careful handling of dog feces is imperative and always washing your hands after handling feces or the dog prior to eating especially.

Symptoms in pets: Diarrhea, visible worms in stool, vomiting, constipation, coughing, bloody stool

Symptoms in humans: Cough, shortness of breath, abdominal pain, blood in stool


#3 – MRSA

Methicillin resistant Staph Aureus is more of a problem from humans to pets. I have treated these infections many times, mostly in ears and wounds. If your pet has non-healing wounds or chronic recurrent ear infections, a culture at your vet would be a really good idea.

Symptoms in pets: Fever, discharge from a wound, skin lesions, skin swelling, slow to heal wounds

Symptoms in humans: Generally start as small red bumps that resemble pimples, boils or spider bites. These can quickly turn into deep, painful abscesses that require surgical draining. Sometimes the bacteria remain confined to the skin.


#4 – Sarcoptic Mange

Often called Scabies, Mange is caused by a tiny mite that burrows deeply into the skin creating severe itching and irritation. Secondary infections are common for infected dogs and it is not only contagious between dogs, but also can infest humans. Humans are a “dead end” host which means the infestation will be self-limiting and infected humans do not lose all of their hair like infected dogs can. But the mites cause profound itching. If your dog is extremely itchy and is missing patches of hair, call your vet right away,especially if your dog has been around other dogs that you don’t own or has been boarded or grooming with other dogs.

Symptoms in pets: The symptoms of mange depend on which type of mite is present. Demodectic mange tends to cause hair loss, bald spots, scabbing and sores. Secondary bacterial infections can make demodectic mange an itchy and uncomfortable disease.  Sarcoptic mange tends to cause intense itching. It can result in restlessness and frantic scratching, symptoms that generally appear one week after exposure. It also can result in hair loss, reddened skin, body sores and scabs. The most commonly affected areas are a dog’s ears, elbows, face and legs, but it can rapidly spread to the entire body.

Symptoms in humans: sarcoptic mange causes a rash of red bumps, similar to mosquito bites. Humans cannot get demodectic mange from dogs.


#5 – Salmonella

Salmonella is a bacteria that can be found in contaminated and undercooked food.  It can make people and dogs very sick with GI signs and I discourage feeding of raw meats in part for this reason. Poultry for example should be cooked to a minimum temperature of 165 degrees to make it safe to eat for pets and people.

Symptoms in pets: Reptile pets and chicks often don’t show symptoms

Symptoms in humans: Abdominal pain, fever, vomiting, headache, nausea



#6 – Ringworm

Dermatophytosis or ringworm is a fungal infection of the skin. I see it in dogs and cats, although cats are more likely to be assymptomatic carriers. I think that animals are often blamed for infections in children, but ringworm can be found in soil where children play.

Symptoms in pets: Skin lesions and patches of hair loss with a red mark in the center

Symptoms in people: Red, circular patches on the skin



#7 – Leptospirosis

Leptospirosis is a bacterial infection that is spread through contact with the urine of an infected animal. Potential sources can be wildlife, like mice and rats. Contaminated standing water is thought to be a source. Infected dogs can be a source for their humans handling their urine so if your dog is sick with fever, lethargy +/- jaundice, please contact your vet immediately.

Symptoms in pets: fever, muscle pain, vomiting and diarrhea, loss of appetite, lethargy, depression, and blood in the urine. More serious infections can cause jaundice and blood clotting problems.

Symptoms in people: High fever, headachem chills, miscle aches, vomiting, jaundice (yellow skin/eyes), red eyes, abdominal pain



#8 – Rabies

Rabies is a virus that can infect mammals. It is spread in the saliva or contact with infected tissues. Suspected rabies or even any human bitten by an unvaccinated (or past due) dog must be reported to the health department. Bats serve as a source in the wild, as do raccoons and other wildlife. There are very few human cases that have survived once the symptoms have evidenced themselves.

Symptoms in pets: Fever, seizures, dropped jaw, inability to swallow, change in bark tone, muscular lack of coordination, excessive salivation or frothy saliva

Symptoms in humans: Temperature of 100.4ºF, chills, fatigue, problems sleeping, lack of appetite, headache, irritability, anxiety, sore throat, vomiting.  Around half of people will also experience pain and a tingling sensation at the site of the infection.



#9 – Hookworms

Hookworms suck on the intestinal lining of dogs, causing a potentially life-threatening blood loss, especially in puppies. The eggs found in pet feces could transfer through the skin in pet owners if you happened to, say, step on a dropping with your bare feet in the backyard.

Symptoms in pets: Diarrhea, weight loss

Symptoms in humans: Often none but could include an itchy rash, cough, wheezing, stomach pain, anemia, or loss of appetite


#10 – Tapeworms

Tapeworms are flat segmented worms that live in the intestines of some animals. Animals can become infected with these parasites when grazing in pastures or drinking contaminated water.

Symptoms in pets: Dragging back end across the ground; rice-like pieces in the pet’s stool or longer worms in pet vomit

Symptoms in humans: nausea, weakness, diarrhea, abdominal pain, hunger or loss of appetite, fatigue, weight loss. rice-like pieces in stool