Roundworm: Roundworm, also known as Toxocara, is a parasite of the small intestine that can be spread to humans through the feces of infected animals. Infection with roundworms is a common cause of visceral or ocular larva migrans in people, which are serious conditions that can irreparably affect the organs and eyes. Young children are the most susceptible.
Tapeworm and fleas. Dipylidium is a common tapeworm of dogs and cats that is spread by fleas. People can become infected by accidental ingestion of an infected flea. Children are particularly susceptible. Proper flea control is the most important means of prevention.
Toxoplasmosis. Toxoplasmosis is an infection caused by a parasite called Toxoplasma gondii. Cats carry the infection and can spread it via contaminated feces. Pregnant women are particularly at risk of passing the disease to their unborn fetus and should be cautious about cleaning out the litter box (scooping the litter box daily generally offers good prevention as it takes at least 24 hours for contaminated stool to become infective). Although cats often get a bad rap when it comes to the spread of toxoplasmosis, it’s important to remember that people who consume raw or undercooked meat or unpasteurized dairy products are also at risk.
Campylobacter: Campylobacter is an infectious bacterial organism that causes diarrhea, intestinal cramping and abdominal pain. People may become ill from coming into contact with the stool of an infected dog or cat. Eating undercooked meat or drinking unpasteurized milk can also expose people to infection from this organism.
Salmonella: Salmonella is a bacteria that can infect dogs, cats and humans causing watery diarrhea, fever and lethargy. The bacteria is spread through the stool of infected animals. An increased risk of infection exists for people who feed their pets raw meat diets.
Lyme Disease and Rocky Mountain Spotted Fever: Lyme disease and Rocky Mountain spotted fever are tickborne illnesses caused by the bacteria Borrelia burgdorferi and Rickettsia ricketsii, respectively. These bacteria are responsible for causing fatal illness in dogs and humans ranging from fever and muscle and joint pain to death. Although the bacteria are spread by ticks that feed off of infected dogs, your dog cannot transmit the disease directly to you. Therefore, prevention lies largely in proper tick control.
Ringworm: Ringworm is a dermatophyte, a type of fungus that can affect the skin, generally causing a ring-shaped rash in humans. In pets, this often shows up as a circular area of hair loss that might or might not be itchy. Dogs and cats, especially puppies and kittens, can carry ringworm, and it is spread by close contact. While not generally a serious condition, infection with ringworm can be unpleasant, nonetheless.