Zoonotic Diseases in City Pets: How to Protect Your Household

By Dr Duncan Houston

Quick Answer

Zoonotic diseases are infections that can pass between animals and people, but ordinary pet ownership does not mean your household is likely to become ill. Reduce risk with handwashing, prompt waste removal, appropriate vaccination and parasite prevention, safe food handling and timely veterinary care. Pregnant people, young children, older adults and people with weakened immune systems may need additional precautions agreed with their healthcare professional.

City pets can encounter contaminated soil, rodents, shared outdoor areas and other animals. Indoor pets can also carry infections or parasites, sometimes without looking unwell. The relevant risk depends on the organism, location and type of contact, rather than simply whether your pet lives in an apartment.

Infections worth understanding

Leptospirosis

These bacteria spread through infected animal urine and contaminated water or soil. Urban rodents can be a source. In dogs, vomiting, marked lethargy, appetite loss, jaundice or changes in urination can accompany serious kidney or liver illness. Seek prompt veterinary care, mention possible exposure and avoid bare-handed contact with urine. Discuss vaccination and local risks with your vet; vaccination reduces risk but does not replace hygiene.

Intestinal parasites and Giardia

Roundworm eggs in contaminated environments can cause disease if swallowed, while some animal hookworm larvae can penetrate human skin. Promptly remove faeces, wash hands after gardening, cover sandpits and follow a parasite plan suited to your pet and region.

Giardia spreads when its microscopic cysts are swallowed. However, CDC guidance explains that people are unlikely to catch Giardia from dogs or cats because the types commonly involved differ. Persistent diarrhoea still needs veterinary assessment. Do not assume routine worming products treat every parasite.

Toxoplasmosis

People can acquire Toxoplasma through undercooked meat, contaminated soil or food, and accidental ingestion of material contaminated by infected cat faeces. Cat ownership alone is not a reason to rehome a cat during pregnancy. Have someone else remove litter daily if possible; otherwise use gloves and wash hands afterwards. Daily removal matters because the parasite usually needs one to five days after shedding to become infectious. Avoid feeding cats raw meat and discourage hunting.

Cat scratches, bites and ringworm

Bartonella, associated with cat scratch disease, is linked to cats and fleas. Use appropriate flea prevention, avoid rough play and do not allow pets to lick broken skin. Bite wounds can also introduce other bacteria and become infected.

Ringworm is a fungal skin infection that can spread through contact with infected animals or contaminated items. Patchy hair loss and scaling need assessment because mites, allergy and other skin conditions can look similar. Follow a confirmed diagnosis with the prescribed animal treatment and environmental cleaning plan; weekly washing alone may be insufficient.

Other animals bring different risks

Reptiles and backyard poultry can carry Salmonella while appearing healthy. Keep them and their equipment away from kitchens, avoid kissing them and wash hands after handling. CDC recommends children under five avoid contact with reptiles, amphibians, poultry and rodents.

Pet birds can transmit psittacosis through infectious material such as dried droppings or respiratory secretions. Sheep, goats and cattle can expose people to Q fever, especially through contaminated birth materials. Get species-specific veterinary advice and tell your healthcare professional about animal exposure if you become ill.

A practical prevention routine

• Wash hands with soap and water after handling waste, animal food or supplies and before eating.
• Keep pet food preparation and waste cleaning separate from human food preparation. Raw pet food can introduce pathogens into the household.
• Keep vaccinations, faecal testing and parasite prevention appropriate to local risks and your pet's lifestyle. There is no single treatment schedule that covers every animal and organism.
• Remove dog waste promptly, clean litter daily and keep ill pets away from communal animal areas.
• Use safe drinking water, manage rodents without exposing pets to poison and clean contaminated surfaces as your vet directs.

When to seek help

Contact a vet promptly for persistent diarrhoea, unexplained skin lesions or suspected exposure. Severe weakness, repeated vomiting, breathing difficulty, collapse or inability to urinate needs urgent care. Tell the clinic before arrival if an infectious disease is suspected.

For a human bite or scratch, wash the wound immediately and seek medical advice for bites, deep wounds, increasing redness, swelling, fever or high-risk individuals. Potential rabies exposure requires urgent medical and public-health advice; do not wait for symptoms. A veterinarian treats the animal, while your own clinician assesses your health.

Frequently asked questions

Can a healthy-looking pet carry germs?

Yes. Routine hygiene remains useful even when your pet appears well.

Should I give up my cat if I am pregnant?

Usually no. Discuss personal risks with your clinician and follow safe litter, gardening and food-handling precautions.

Does monthly worming prevent all zoonotic disease?

No. Products target particular parasites and do not prevent bacterial or fungal infections. Your vet should choose the plan.

Can I catch every infection my pet has?

No. Many infections are species-specific. Ask about the confirmed diagnosis rather than assuming all diarrhoea or skin disease is contagious to people.

Further guidance is available from CDC Healthy Pets, Healthy People and the Cornell Feline Health Center.

ASK A VET™ can help you understand your pet's symptoms and prevention needs, while your healthcare professional advises on any risk or illness affecting you.