Transmission of Parasitic Diseases

Pets can carry parasites and pass parasites to people. Proper handwashing can greatly reduce risk.

A zoonotic disease is a disease spread between animals and people. Zoonotic diseases can be caused by viruses, bacteria, parasites, and fungi. Some of these diseases are very common. For zoonotic diseases that are caused by parasites, the types of symptoms and signs can be different depending on the parasite and the person. Sometimes people with zoonotic infections can be very sick but some people have no symptoms and do not ever get sick. Other people may have symptoms such as diarrhea, muscle aches, and fever.

Foods can be the source for some zoonotic infection when animals such as cows and pigs are infected with parasites such as Cryptosporidium or Trichinella. People can acquire cryptosporidiosis if they accidentally swallow food or water that is contaminated by stool from infected animals. For example, this can happen when orchards or water sources are near cow pastures and people consume the fruit without proper washing or drink untreated water. People can acquire trichinellosis by ingesting undercooked or raw meat from bear, boar, or domestic pigs that are infected with the Trichinella parasite.

Pets can carry and pass parasites to people.

Some dog and cat parasites can infect people. Young animals, such as puppies and kittens, are more likely to be infected with roundworms and hookworms.

Wild animals can also be infected with parasites that can infect people. For example, people can be infected by the raccoon parasite Baylisascaris if they accidentally swallow soil that is contaminated with infected raccoon feces.

Regular veterinary care will protect your pet and your family.

There are simple steps you can take to protect yourself and your family from zoonotic diseases caused by parasites.

• Make sure your pet is under a veterinarian’s care to help protect your pet and your family from possible parasite infections.
• Practice the four Ps: Pick up Pet Poop Promptly, and dispose of properly. Be sure to wash your hands after handling pet waste.
• Wash your hands frequently, especially after touching animals, and avoid contact with animal feces.
• Follow proper food-handling procedures to reduce the risk of transmission from contaminated food.
• For people with weakened immune systems, be especially careful of contact with animals that could transmit these infections.

Related Links

• What Every Pet Owner Should Know About Roundworms & Hookworms
• Toxoplasmosis: An Important Message for Women [PDF – 2 pages]
• Toxoplasmosis: An Important Message for Cat Owners [PDF – 2 pages]

Microscopic red blood cells

Triatomine bugs are the vectors for Chagas disease.
Credit: CDC

Parasites can live in natural water sources. When outdoors, treat your water before drinking it to avoid getting sick.

Water is an essential resource for life. Water is used by everyone, every day. Not only do all people need drinking water to survive, but water plays an important role in almost every aspect of our lives – from recreation to manufacturing computers to performing medical procedures. When water becomes contaminated by parasites, however, it can cause a variety of illnesses.

Globally, contaminated water is a serious problem that can cause severe pain, disability and even death. Common global water-related diseases caused by parasites include Guinea worm, schistosomiasis, amebiasis, cryptosporidiosis (Crypto), and giardiasis. People become infected with these diseases when they swallow or have contact with water that has been contaminated by certain parasites. For example, individuals drinking water contaminated with fecal matter containing the ameba Entamoeba histolytica can get amebic dysentery (amebiasis). An individual can get Guinea worm disease when they drink water that contains the parasite Dracunculus medinensis. If an infected person with an open Guinea worm wound enters a pond or well used for drinking water, they can spread the parasite into the water and continue the cycle of contamination and infection. Schistosomiasis can be spread when people swim in or have contact with freshwater lakes that are contaminated with Schistosoma parasites.

Americans traveling abroad should take the necessary precautions to protect themselves from waterborne illness if they plan on being in countries with unsafe drinking water or recreational water. Individuals spending time in the wilderness should also follow the appropriate steps to ensure the safety of their water.