Zoonotic diseases, or zoonoses, are diseases that can be transmitted from animals to people and from people to animals.
There are five zoonoses I want to talk about today, and these five are normally passed from animals to people rather than the reverse. These five diseases are relatively common and can be acquired from your puppy or kitten, or adult dog or cat.
The primary means of contamination for these diseases is understood to be fecal-oral, but this obviously applies to the way in which your pet acquires the infection rather than the manner in which the disease is transmitted from your pet, to you. People pick up these infections in a variety of other ways, which I’ll discuss shortly.
Hookworms are primarily transmitted fecal-orally to animals. Your pet may eat contaminated feces or dirt, or he might run through contaminated soil, then lick his paws and ingest the eggs in that manner.
Fortunately, since people aren’t coprophagic, meaning we don’t consume feces, that’s not how we acquire a hookworm infection. Instead, we pick up the eggs or larvae on our skin from soil contaminated by infected wild animal or pet poop.
These microscopic parasites aren’t visible to the naked eye, so looking down as you wander barefoot around your yard or garden won’t help!
To prevent a hookworm infestation, it’s important to get rid of any potentially infective feces from wild or stray animals around your property that might tempt your dog or a barefoot two-legged member of your family. It’s also a good idea to keep your pet away from the poop of other animals while you’re walking or hiking outdoors.
Puppies and kittens can acquire hookworm from their mother’s milk, if the nursing mom has an infestation.
In people, the common route of hookworm infection is through skin. Hookworm larvae have the ability to penetrate human skin - not a pleasant thought, I know, but true!
A rash typically forms at the site where the hookworm larva penetrates the skin. The most common area for a rash is on the feet of a person who has walked barefoot in sand or soil containing hookworm larva.
People who garden without gloves and handle contaminated soil will notice a rash on their hands if they’ve been infected.
It’s also possible to acquire a hookworm skin infection in the form of a “traveling rash.” If you’ve been exposed to possibly contaminated soil and you have a mysterious rash moving around on your skin, your doctor will be able to determine if you’ve picked up a hookworm infection.
Hookworm infection in your pet can’t be taken lightly. A puppy or kitten who acquires hookworms can become lethargic, weak, malnourished and anemic. It isn’t uncommon for young pets to die from such an infestation.
Infected adult dogs and cats may show symptoms of poor appetite and weight loss.
Roundworms are large, and spaghetti-like in appearance. And they can create a full-blown infestation in your pet before you know they’re there.
By the time you see signs of roundworms in your dog’s or cat's feces or vomit, he’s overrun with them. Don’t count on seeing roundworms or hookworms to alert you to an infestation. If you suspect your pet has been exposed, you should collect a stool sample and drop it by your vet’s office for analysis.
Your pet will typically acquire a roundworm problem by eating infected feces. The infection can also be passed from a female to her unborn puppies or kittens across the placenta. The babies develop their own infection while still in the uterus and are born positive for roundworm.
Roundworm infections in people are most commonly transmitted through ingestion of contaminated soil. For example, if you pull vegetables from your garden and don’t wash them thoroughly, you could ingest soil that is contaminated with roundworm eggs.
Because humans are not the perfect host for roundworms, they tend to travel through the body and create problems like organ inflammation.
In fact, they are known to migrate through the eyes of small children. It is not uncommon for an eye doctor to discover roundworm larva at the back of a child’s eye.
For obvious reasons, it’s very important that puppies and kittens be dewormed if they are carrying a worm parasite like hook or roundworm. I recommend you have fecal specimens checked at six, eight, ten and twelve weeks.
An infected pet new to your family creates an unacceptable potential for exposure – especially when it comes to young children.
Toxoplasmosis is a zoonotic disease any warm-blooded vertebrate can acquire, however, infections are most common in cats and humans.
Most at risk are pregnant women and people who are immunosuppressed. For example, an AIDS patient runs a much greater risk of acquiring a toxoplasmosis infection than a person with a healthy immune system. Children are also at higher risk.
If your cat has the disease, she may show no signs of it. Cats that spend time outdoors – especially if they hunt small prey – are more likely to acquire toxoplasmosis. If your outdoor kitty is eating rabbits or rodents or is getting other raw meat from animals that could be toxoplasmosis-positive, she can become infected.
This is why many doctors recommend pregnant women not scoop or sanitize their cat’s litter box. If you have a toxoplasmosis-positive kitty, she’s apt to be shedding the infection into her stool.
If you have a cat and are pregnant or your immune system is compromised for any reason, either assign litter box chores to another family member, or be vigilant about wearing gloves when you handle the box.
You also shouldn’t handle raw meat, another potential source of toxoplasmosis exposure.
If you feed your pet a raw food diet, I recommend you freeze fresh meat for three days to kill off any toxoplasmosis living in the tissues. This will make the meat safer for you to handle and healthy for your pet to eat.
Cryptosporidiosis, or crypto for short, is a protozoan parasite. This parasite loves water.
Infected animals can transmit crypto by defecating in ponds, lakes and other bodies of water.
Your dog or cat can acquire crypto by drinking contaminated water or eating the feces of a contaminated animal.
People typically acquire the disease through swimming or other contact with contaminated water.
#5: Lyme disease
Lyme disease is a vector-borne illness. The vector is the vehicle of transmission, in this case it is the Ixodes tick, also known as the deer tick or black-legged tick.
The tick transmits the Lyme organism, a spirochete, to a dog or a person and both can become infected.
Acute Lyme disease causes fever and lethargy. People also tend to get rashes, and dogs tend to develop transient lameness along with the other symptoms.
In a chronic Lyme infection, dogs, people and also cats (though less likely) can develop polyarthritis, an immune-mediated degenerative disease, which can lead to kidney disease.
Tips for Staying Parasite-Free
So how do you keep your family and pets safe from these zoonotic disease-carrying parasites? A few recommendations:
- Wash all vegetables thoroughly before you serve them to any family member, human or fur covered.
- If you garden, wear shoes and gardening gloves. Wash your hands and other exposed skin if you come in contact with soil.
- Prevent pets and other animals from using your child’s sandbox as a toilet. It’s important to keep playground sand and sand boxes covered when not in use.
- Practice good tick protection. Do regular tick checks on your kids and your pets. If necessary, use safe tick repellants to prevent tick attachment.