By: Dr. Angela LehmanWhat does “zoonotic” mean?

The term “zoonotic” refers to any disease that can be passed from an animal to a human. Certain parasites, bacterial infections, fungal infections, and even viral infections can be transmitted in this way. Although we share our homes, our yards, and sometimes even our beds with our beloved pets, one thing we should NOT be sharing is disease! One important example of a zoonotic disease, especially in children, is caused by a common internal parasite known as the roundworm. 

Roundworms and your pets 

Roundworms, or ascarids, are a common health problem in puppies and kittens. Symptoms often include vomiting and/or diarrhea, which in severe cases can cause life-threatening complications. Infection can occur while the puppy is still in the uterus, or through nursing (in puppies and kittens.) Pregnant animals as well as young puppies and kittens can be treated for roundworms safely and easily if infection is suspected. Many pets will have already been treated for roundworms, sometimes more than once, before they arrive home from the breeder or shelter.  An adult animal can become infected by ingesting one of the microscopic eggs through grooming, usually after close contact with an infected animal, or through contact with contaminated soil. In an infected animal, the roundworms mature and produce eggs which are then shed through the animal’s feces to be picked up by other animals or humans, potentially causing them to become infected as well. Your veterinarian can advise you as to the proper diagnosis and treatment for your pet. 

Why treat more than once?

The roundworm goes through several stages during its life cycle, from egg to immature larva to mature roundworm over a period of between 5 and 10 ½ weeks, depending on the species. The canine (dog) roundworm takes 6 weeks to fully develop. Common treatments may not work at all stages of the parasite’s life cycle, so animals are usually medicated multiple times to clear the infection.

 Note: It can take several days to weeks for the eggs to become infective to other animals, so picking up after your pet in a timely manner greatly reduces the chances of spreading the infection to other animals or people. If not removed from the environment, roundworm eggs can survive for months to years and may reinfect your pets at any time. 

How can roundworms cause zoonotic disease? 

Each species of roundworm is adapted to survive within a specific species of animal. Certain Toxocara and Toxascaris species of roundworms are specifically adapted to survive within the bodies of dogs and cats, while the roundworm known as Baylisascaris is adapted to survive within raccoons. If a human accidentally ingests a roundworm egg from a dog, cat or raccoon, the developing larva will become confused in the strange environment and will migrate from the foreign digestive tract to various organs throughout the body, potentially causing serious health problems. This process is known as visceral larva migrans. An immature larva that migrates to the eye can lead to blindness in a specific process known as ocular larva migrans. If a human picks up the microscopic eggs on his or her hands, through contact with an infected animal or contaminated soil, then accidental ingestion may occur unless thorough hand-washing techniques are followed regularly. These disease processes are especially important concerns for young children or adults with weakened immune systems.   How can I keep my family and myself safe?

Here are a few easy steps to keep you and your family safe from roundworm infections:  

Maintain good hygiene at all times – This means washing hands thoroughly after petting or playing with your pets (especially puppies and kittens,) as well as cleaning up after them in a timely manner

Have your pets screened for internal parasites regularly by your veterinarian – This means diligently testing puppies and kittens multiple times during the first several weeks of life (usually as part of the new puppy or kitten exam and appointments for vaccine boosters,) as well as each year during your pet’s annual wellness exam. Many products are now available to prevent internal parasites on a monthly basis in dogs and cats; please contact your veterinarian if you are interested in learning more about monthly prevention. 

Practice extreme caution around raccoons – This means avoiding any areas where raccoons are known to frequent, and refraining from feeding raccoons or otherwise encouraging them to live near houses or playgrounds. Children should be taught never to approach a raccoon for safety reasons.  

Do not hesitate to contact your veterinarian if you have any additional questions about internal parasites, zoonotic diseases, or any other concerns about your pet’s health. If you believe that you or someone you know may have been exposed to a zoonotic disease, please seek the attention of your personal physician or pediatrician at once. For more information on roundworms we recommend visiting the following websites:

http://www.petsandparasites.org/
http://www.cdc.gov/ncidod/dpd/parasites/toxocara/default.htm
http://www.cdc.gov/ncidod/dpd/parasites/baylisascaris/default.htm