While most animals are loving companions and fascinating creatures, some can carry diseases that may be transmitted to humans. These diseases, known as zoonotic diseases, can spread through direct contact or through bites, scratches, or even by being in close proximity to animals.
The good news is that by following basic precautions, you can enjoy your time with your pets and other animals while minimizing health risks. Here are some diseases that can be passed from animals.
This article provides general information about zoonotic diseases. Not every animal carries these diseases, and the risk of transmission is often low. While we are not health experts, we recommend practicing basic hygiene, such as washing hands after handling animals, and ensuring your pets receive regular veterinary care.
If you have specific concerns about disease transmission or health risks, it’s always best to consult with a healthcare professional or veterinarian.
1. Rabies
Once symptoms appear, this viral disease is almost always fatal. Transmitted primarily through the bite of infected mammals like bats, foxes, raccoons, and skunks, rabies attacks the central nervous system with devastating effects.
Early vaccination after exposure can prevent the disease from developing. Worldwide, dogs are responsible for most rabies cases in humans, though in North America, wild animals pose the greatest risk. Keep pets vaccinated and avoid handling wildlife, especially animals behaving strangely.
2. Salmonella
Found in the intestinal tracts of many animals, Salmonella bacteria cause severe stomach cramps, fever, and diarrhea that can last for days. Pet reptiles, backyard chickens, and contaminated eggs or meat are common sources.
Children under five often get infected after handling pet turtles or lizards, then putting their fingers in their mouths. Simple precautions make a difference: wash hands after animal contact, cook food thoroughly, and keep kitchen surfaces clean to prevent this uncomfortable infection.
3. Toxoplasmosis
Did you know that one-third of the world’s population carries the Toxoplasma parasite? Cats acquire it from hunting infected mice or birds, then shed infectious eggs in their feces.
Humans become infected by accidentally ingesting these microscopic eggs when cleaning litter boxes or gardening in contaminated soil. While healthy adults rarely show symptoms, the infection can cause serious complications for pregnant women and their unborn babies. Pregnant women should avoid changing cat litter or wear gloves if necessary.
4. Ringworm
Despite its name, ringworm isn’t caused by a worm at all. This fungal infection creates circular, red, itchy patches on the skin that sometimes resemble a worm’s shape.
Puppies, kittens, and farm animals commonly carry the fungus without showing symptoms. The infection spreads through direct contact with an infected animal’s skin or fur. Shared brushes, bedding, or towels can also transmit the fungus. Regular bathing of pets and good hygiene practices help prevent this annoying but treatable condition.
5. Leptospirosis
Rodents and farm animals carry Leptospira bacteria in their kidneys, shedding them in urine that contaminates soil and water. The bacteria can survive for weeks in puddles, lakes, and moist soil.
Humans contract this illness when contaminated water enters through cuts in the skin or through the eyes, nose, or mouth. Campers, farmers, and flood cleanup workers face the highest risk. Early symptoms mimic the flu but can progress to kidney and liver damage if untreated. Avoid swimming in potentially contaminated water after heavy rainfall.
6. Campylobacter
As the most common bacterial cause of diarrheal illness in Canada, Campylobacter lurks in raw poultry and unpasteurized milk. A single drop of juice from raw chicken can contain enough bacteria to cause illness.
Farm animals carry these bacteria naturally in their intestines without getting sick themselves. People develop fever, cramps, and bloody diarrhea about 2-5 days after exposure. The infection typically resolves without antibiotics, but severe cases can trigger Guillain-Barré syndrome, a serious neurological condition. Always cook chicken thoroughly and use separate cutting boards.
7. Lyme Disease
Tiny blacklegged ticks serve as vectors for the corkscrew-shaped bacteria behind Lyme disease. These ticks acquire the bacteria by feeding on infected mice and other small mammals before passing it to humans.
The signature bull’s-eye rash appears in about 70-80% of infected people. Left untreated, the infection can spread to joints, the heart, and nervous system, causing serious complications months or years later. Ticks must typically feed for 36+ hours to transmit the bacteria, making daily tick checks after outdoor activities crucial for prevention.
8. Q Fever
Farm workers face an invisible threat when working with livestock. Q fever bacteria spread through airborne particles from infected animals, particularly during birthing processes when bacteria concentration is highest.
The bacteria can survive harsh environments for months and travel on wind currents far from their source. Many infected people show no symptoms, while others develop a severe flu-like illness with high fever, severe headaches, and extreme fatigue. Complications can include chronic inflammation of the heart valves. Pregnant women and those with heart valve problems face the greatest risk.
9. Cat Scratch Disease
Those adorable kitten scratches can deliver more than momentary pain. When a cat’s claws become contaminated with flea dirt containing Bartonella bacteria, a scratch can introduce these pathogens under your skin.
Symptoms typically include swollen lymph nodes near the scratch site, fatigue, and low-grade fever. Kittens under one year old pose the highest risk as they’re more likely to carry the bacteria without showing signs of illness. While usually mild in healthy people, the infection can cause serious complications in those with weakened immune systems.
10. Hantavirus
Opening that long-abandoned cabin or shed could expose you to hantavirus particles. These viruses lurk in dried rodent urine, droppings, and saliva, becoming airborne when disturbed.
Unlike many zoonotic diseases, hantavirus infections can’t spread between people. The early symptoms resemble flu, but rapidly progress to life-threatening respiratory failure as lungs fill with fluid. Prevention focuses on rodent control and careful cleaning of rodent-infested areas using wet methods rather than sweeping or vacuuming, which can aerosolize the virus.
11. Psittacosis
Bird enthusiasts beware: psittacosis bacteria thrive in pet birds like parrots, cockatiels, and budgies. The infection spreads when people inhale dried bird droppings or respiratory secretions that become airborne during cage cleaning.
Even apparently healthy birds can shed the bacteria. Symptoms range from mild respiratory illness to severe pneumonia with high fever, headache, and difficulty breathing. Regular cage cleaning, good ventilation, and wearing a mask when handling bird materials reduce transmission risk. Infected birds can be treated with antibiotics, protecting both the pet and owner.
12. Brucellosis
Farmers, veterinarians, and dairy workers face occupational exposure to Brucella bacteria through contact with infected animals. For consumers, the primary risk comes from consuming unpasteurized milk products from infected cows, sheep, or goats.
The bacteria cause a debilitating illness with fever that comes and goes, joint pain, and extreme fatigue that can persist for months or years. In some regions, brucellosis is called “undulant fever” because of its wave-like pattern of symptoms. Pasteurization effectively kills the bacteria, making commercial dairy products safe.
