Zoonotic Diseases
🌍 What Are Zoonotic Diseases?
Zoonotic diseases (or zoonoses) are infections that spread between animals and humans. They can be caused by viruses, bacteria, parasites, or fungi—many of which may be carried by animals that appear healthy.
Scientists estimate that >6 out of every 10 known infectious diseases in people are zoonotic, and 3 out of 4 new or emerging diseases come from animals. Learning how they spread is key to preventing illness.
How Germs Spread Between Animals and People
- Direct contact: Through bites, scratches, saliva, blood, urine, or other body fluids.
- Indirect contact: Via contaminated surfaces, habitats, animal food/water dishes, soil, coops, or cages.
- Vector-borne: Transferred through insect bites—ticks, mosquitoes, fleas.
- Foodborne: Consuming contaminated food or beverages—like unpasteurized milk, undercooked meat or eggs, or produce tainted by animal feces.
- Waterborne: Contact with water contaminated by animal waste.
Who Is at Higher Risk?
- Children under 5, adults 65 and older, pregnant individuals, and those with weakened immune systems.
- People who work closely with animals—livestock handlers, veterinary staff, wildlife professionals, and outdoor workers.
Protect Yourself and Your Family
- Wash hands often, especially after being around animals, even if you didn’t touch them. Use soap and water—or hand sanitizer with ≥60% alcohol.
- Prevent bites from mosquitoes, ticks, and fleas—use repellents, wear long clothing, and treat pets for parasites.
- Handle food safely—thoroughly cook meat and eggs, wash produce, and avoid unpasteurized products.
- Avoid unsafe contact with wildlife or unfamiliar animals.
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For more on how zoonotic diseases cross the human-animal-environment divide, visit the CDC's One Health & Zoonotic Diseases overview.