Many parasites can transmit disease to your pet, but you may not always know when your furry pal has a parasitic infection. Parasites, like fleas, ticks, and mosquitoes are sneaky, and can transmit a wide variety of diseases to your pet, some of which may not cause obvious illness signs. Read our All Creatures Animal Hospital team’s guide to learn how to recognize parasitic disease illness signs in your pet, and how to protect them from these pests.

Pets’ parasitic disease signs

Parasites commonly bug our pets, and these pests are everywhere—outdoors and indoors—year-round. Pets’ most common parasitic diseases—and their signs—include:

  • Intestinal parasite infections — Roundworms, tapeworms, hookworms, whipworms, Giardia, and coccidia are among the most common intestinal parasites, and typically cause your pet diarrhea, vomiting, lethargy, weight loss, a poor hair coat, and a pot-bellied appearance. Sometimes, however, infected pets show no parasitic disease signs. Pets generally contract intestinal parasites from ingesting contaminated water or feces. 
  • Heartworm disease — An infected mosquito’s bite can transmit heartworm disease to your pet. These parasites travel to the blood vessels near your pet’s heart and lungs, causing an initial mild, persistent cough. As the disease progresses, your pet can become lethargic and exercise intolerant, and may develop a bloated abdomen caused by fluid buildup. Cats may have asthma-like signs—wheezing and difficulty breathing—and may also vomit, have diarrhea, or suddenly collapse.
  • Tick-borne illnesses — Ticks transmit many diseases—Lyme disease, anaplasmosis, ehrlichiosis, Rocky Mountain spotted fever, and more. Although these diseases are different, all tick-borne illnesses can cause many of the same vague illness signs—lameness, lethargy, fever, swollen lymph nodes, and abnormal bruising and bleeding.

Now that you are familiar with pets’ parasitic diseases and signs, determine whether the following statements are fact or fiction:

Fact or fiction: Parasites are only a threat to my pet during warm months

Fiction: Although parasites are more active during the warmer months, fleas, ticks, and mosquitoes can pop up any time the temperature is higher than 35 degrees. One mild winter day can expose your pet to a flea infestation, heartworm disease, Lyme disease, ehrlichiosis, anaplasmosis, and other tick-borne illnesses. Intestinal parasite eggs can hibernate and remain viable in the environment, and if your pet eats one of these parasite eggs, they can become infected any time of year, so ensure your pet receives their parasite prevention medication year-round.

Fact or fiction: I see no worms, so my pet must be parasite-free

Fiction: Many worm types are not visible or recognizable as worms, and can infect your pet. You may notice spaghetti-like roundworms in your pet’s stool, or rice-sized tapeworm segments in their fur, but most worms are microscopic, requiring special equipment for diagnosis. Hookworms and whipworms are two intestinal parasites that can cause diarrhea, vomiting, and weight loss, but they are extremely difficult—if not impossible—to spot without a microscope.

Another worm you cannot observe is a heartworm, because these parasites live within the large blood vessels surrounding your pet’s heart and lungs. If the heartworm population reaches a high enough level, they can enter your pet’s heart.  

Because a microscope is necessary to spot intestinal worms and heartworms, your veterinarian will regularly check your pet’s stool and blood to spot an infection, and administer treatment before serious health issues occur.

Fact or fiction: Puppies and kittens are at an increased risk for parasitic diseases

Fact: Pets of all ages are at risk for parasitic diseases. Puppies and kittens can contract roundworm infections before birth or while nursing, because these intestinal worms can travel through the placenta or mother’s milk. In addition, puppies and kittens have weaker immune systems than adult pets, so they are more likely to experience severe illness from flea infestations, roundworms, hookworms, whipworms, Giardia, and coccidia. Because young pets are so susceptible to parasitic diseases, many parasite preventives have been developed to be safe for use in pets 6 to 8 weeks of age. 

Fact or fiction: My pet never leaves the house or yard, so they cannot contract parasites

A cat sits on a window sill, gazing outside. The window is open, revealing lush green foliage. Sunlight filters through the glass, creating a warm and serene atmosphere inside the room—the perfect scene for a vet to observe the relaxed feline's health and happiness.

Fiction: Although your pet may be a homebody, they can contract parasitic diseases. Fleas and ticks can hitch a ride on your pants leg, and enter your home to latch onto your pet. Mosquitoes can easily flit inside through open doors. In addition, you may inadvertently step in feces contaminated with intestinal parasite eggs, bringing these parasites inside your home, where your pet may ingest them. Also keep in mind that fleas, ticks, and parasite eggs can latch on to your dog, who can bring parasites inside your home, and affect your indoor-only cat, so protect all your pets from parasitic disease by ensuring they receive their year-round parasite prevention medicine.

Because pet parasites are so difficult to detect without our veterinary team performing specialized testing, bring in your furry pal, so we can check them for intestinal parasites, heartworms, fleas, and ticks. Contact our All Creatures Animal Hospital team for an appointment, and to pick up your pet’s parasite prevention medication.