History

• One of the most common ways for a disease to pass to humans is through fecal material. Toxoplasmosis is caused by a parasite that infects rats and birds that are then attacked and eaten by cats. The cats ingest the parasite and deposit millions of them in their feces over the three-week infection. Humans come in contact with the parasites and accidentally ingest them when changing the cat litter box or eating food that has had contact with cat feces.
  
  

Feces

• Zoonotic diseases have been around for millennia and scientists have found the bacteria that cause some forms of arthritis in both prehistoric man and dinosaurs. Cats and rodents were identified as carriers of toxoplasmosis as early as 1903 and later identified as an agent for the disease until 1932. Doctors and veterinarians have spent years learning about diseases that can be passed from cats to humans and working to educate the public, because some of these diseases can be deadly.
  
  

Fluid

• Some zoonotic cat diseases are commonly passed on via bodily fluid such as blood and saliva. Rabies is a viral disease to which all mammals, including cats, are susceptible. Rabies causes erratic and often aggressive behaviors in animals and is transmitted via infected saliva through a bite. A lower food chain animal such as a rat or bat is usually the primary carrier, and then infects a higher order mammal such as a cat. This results in the higher order animal, usually a pet, becoming aggressive and biting a human.
  
  

Scratching

• A cat scratch often leads to a bleeding wound, and that can be the perfect opportunity for bacteria. Almost 90 percent of cat scratch fever cases are caused by the bite, lick or scratch of a cat. The bacteria may have been transferred to the claws during cleaning, and transferred to a human after a scratch, often during play.
  
  

Types

• There are many types of diseases that can be transferred from cats to animals. Round and hook worms live inside the animal and are contracted by humans through cat feces. Parasitic infections include giardia and cryptosporidim. Both of the diseases cause diarrhea in cats and animals. Bacterial diseases include salmonella, streptococcus and staphylococci and Black Plague. Cats often show no signs of having many of the diseases and can harbor them for months.