Talking with U of M

Talking pets and parasites with U of M

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In the summer months, household pets risk contact with a wide variety of parasites. Dr. Amy O’Brien, an assistant professor in the College of Veterinary Medicine, shares her expertise on preventative measures and next steps if you are concerned about your dog or cat.  

Q. What parasites do dogs and cats risk coming into contact with in Minnesota?
In Minnesota, dogs and cats are at risk of contracting heartworm, intestinal parasites, fleas and ticks. Heartworm is transmitted by mosquitoes, whereas intestinal parasites are ingested by dogs and cats eating grass/dirt or by eating the host, such as a flea. Fleas are commonly found on a variety of mammals and avian species in the environment—wild rabbits and bunnies are a common backyard animal that can carry fleas. Ticks are found in grass and wooded areas and are commonly found on a variety of wild mammals, rodents and avian species. The most common parasites are fleas and ticks. 

Q. What diseases or conditions do fleas and ticks transmit?
Fleas are a bothersome parasite that cause significant itching in dogs and cats. Once a patient has fleas, they usually develop tapeworms due to flea ingestion. In rare cases, some patients develop a flea bite hypersensitivity causing them to be allergic to the material in the saliva. If the number of fleas on a patient is significant enough, it can cause anemia—low red blood cell count—which can lead to death if not caught in time. Although rare, fleas can spread certain types of bacteria that can cause disease in both dogs and cats as well as people. 
The most common tick-borne diseases we see in Minnesota are Lyme disease and anaplasmosis in dogs. Other less common tick-borne diseases in Minnesota that infect both cats and dogs include ehrlichia and babesia, though cases could increase in the future given changes in tick migration patterns in the Midwest. Performing yearly heartworm and tick-borne disease screening is recommended to check for exposure to a tick-borne disease so owners can monitor for clinical signs to develop. 

Q. Are there treatments available?
There are a variety of products that help eliminate a flea infestation, but it is a long and frustrating process. It is important to remember that there are also eggs and larvae on the patient—and in their environment or home—that may not be affected by these products until the flea develops into an adult. Therefore, it is imperative that the patient and all other dogs and cats in the household use flea preventative for at least three months to ensure there is no host for them to live on. Tapeworms transmitted by fleas can be easily treated with medication from your veterinarian. Hypersensitivity reactions, anemias and most other bacteria transmitted by fleas can be treated if they are caught in time. 

The majority of tick-borne diseases can be treated, but there is a possibility of long-term side effects from the bacteria depending on where it affects that patient. For instance, lyme nephritis is a rare condition where bacteria causes damage to the kidneys of dogs. 

Q. How do I know if my pet has a parasite? 
: Fleas typically cause significant itching in dogs and cats. Patients that develop tapeworms will often have rice-shaped segments near the anus. 

Depending on the type and age of the tick, you may never know your dog or cat has a tick. Deer ticks and nymphs of other ticks are very small and can be very difficult to find even with dogs and cats with fine fur. Most commonly, owners will see a small bug crawling on the fur, an attached tick, or an engorged tick that has been attached to the skin for days. The bacterium that can be transmitted from ticks can cause a variety of symptoms and signs including shifting leg lameness, fever, decreased appetite, lethargy, etc. 

Q. Which preventatives work best? 
There are a variety of flea and tick preventatives on the market. It is important to note that many of these products work in different ways. Some will kill fleas and ticks as they walk along the skin while others require the flea or tick to bite to get the product. Some products have a repellent. For ticks, the goal is to kill the tick before it can be attached long enough to transmit the bacteria that can cause tick-borne disease. It is important to work with your veterinarian to determine the best product for your pet. There are over-the-counter products on the market, but some of these products have a narrow margin of safety and/or shouldn't be used around cats.  


About the College of Veterinary Medicine
The University of Minnesota College of Veterinary Medicine affects the lives of animals and people every day through educational, research, service, and outreach programs. Established in 1947, the University of Minnesota College of Veterinary Medicine is Minnesota’s only veterinary college. Fully accredited, the college has graduated over 4,000 veterinarians and hundreds of scientists. The college is also home to the Veterinary Medical Center, the Veterinary Diagnostic Laboratory, the Leatherdale Equine Center and The Raptor Center. To learn more, visit

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