Pets are commonly targeted by parasites, resulting in significant health problems. Our Memorial Villages Animal Hospital team wants to provide case studies about common parasitic pet diseases to help you understand your pet’s risk and ensure you know how to protect your four-legged friend from these conditions. 

Case study #1: Dexter, a 3-year-old Labrador retriever, presented for exercise intolerance

According to Dexter’s owner, he was usually an extremely active, exuberant dog, but lately had been lagging behind during walks and unwilling to play fetch. He was eating well and showed no other signs, except for the occasional cough. Dexter’s physical examination, complete blood count (CBC), and biochemistry profile were all normal. However, Dexter’s owner admitted that Dexter had not been heartworm tested for more than a year, and had missed several doses of his heartworm prevention medication over the last year. So, we performed a heartworm antigen test that showed Dexter was infected. We started him on a lengthy treatment regimen to slowly kill off the parasites at every life stage, and six months later, he is doing well and mostly back to his normal self. 

Heartworm disease doesn’t always end so favorably. Factors you should know about these deadly parasites include:

  • Heartworms are transmitted by mosquitoes — When a mosquito takes a blood meal from an infected dog or wild canid, they ingest baby heartworms (i.e., microfilariae). When the infected mosquito feeds on your pet, they can transmit the parasites.
  • Signs may be vague — Pets don’t typically show signs in the initial stages, and begin to appear only when their condition is advanced. In dogs, signs include lethargy, weight loss, a soft persistent cough, and a pot bellied appearance. In cats, signs include increased respiratory effort, wheezing, and decreased appetite. 
  • Treatment is risky — In dogs, treatment is risky, because too many parasites may die off too soon, causing a potentially fatal inflammatory response. No treatment is available for cats, and prevention is the only option.
  • Heartworms can be prevented — You can prevent heartworm disease in your pet with yearly testing and year-round heartworm prevention medication.

Case study #2: Kirby, a 3-month-old domestic short-haired kitten, presented for weight loss

Kirby’s owner had recently adopted her, and despite eating well, she seemed to be losing weight. Her owner was feeding her the correct amount of appropriate kitten food. On physical examination, Kirby’s hair coat was poor, and her body conditioning score (BCS) was three, indicating she was significantly underweight. Kirby’s CBC and biochemistry profile were normal, but her fecal check revealed a roundworm infection.

Our team recommended an appropriate deworming medication, and Kirby quickly gained weight. She is an active, normal kitten today. Factors you should know about these parasites include:

  • Roundworms are common — Roundworms are the most common intestinal parasites in dogs and cats. They are transmitted in several ways, including ingestion in the environment, eating infected birds and small animals, in utero, and through the mother’s milk. 
  • Signs may not be present — Many infected adult cats show no signs, but they can spread the parasites in their feces.
  • Serious complications can occur — Roundworms can migrate through the pet’s lungs, causing respiratory issues, and a high worm load can cause an intestinal blockage.
  • Humans are susceptible — Roundworms can be transmitted to humans who contact contaminated feces or soil. Children are at increased risk of infection from roundworms, which can travel throughout the body, including the liver, lungs, central nervous system, and eyes.
  • Roundworms can be prevented — Many heartworm prevention medications also protect against roundworms. Your pet should receive year-round protection.

Case study #3: Linus, a 2-year-old Chesapeake Bay retriever, presented for lameness

A brown dog, wet from playing, runs energetically across a grassy field with a blue ball in its mouth. Its ears and tail are perked up in alertness and motion, showcasing

Linus’ owner had noticed that his dog seemed stiff and possibly lame, although the lameness was hard to pinpoint and seemed to shift limbs. On physical examination, Linus’ temperature was mildly elevated at 103 degrees—normal is 101 to 102.5 degrees—and his submandibular lymph nodes were slightly swollen. Linus’ blood work revealed slightly elevated white blood cells, but no other abnormalities. Linus’ owner enjoys hiking with the dog in rural areas, and frequently has to remove ticks from Linus. An in-house test was positive for Lyme disease, and further testing revealed high antibodies against the Lyme pathogen.

After three months of treatment, Linus continues to have an occasional fever, but his antibody levels are dropping, so continued treatment hopefully will eradicate the disease. Factors you should know about Lyme disease include:

  • Lyme disease is transmitted by ticks — Several tick species found in Texas, including the Lone Star tick, black-legged tick, brown dog tick, and American dog tick, transmit Lyme disease and other tick-borne illnesses.
  • Signs can be non-specific — Signs include lethargy, swollen lymph nodes, fever, and joint pain, similar to other tick-borne illnesses (e.g., ehrlichiosis, anaplasmosis, and Rocky Mountain spotted fever).
  • Complications can occur — If the bacteria that cause Lyme disease attack your pet’s kidneys, kidney failure can occur.
  • Lyme disease can be difficult to treat — Lyme disease is typically responsive to a particular antibiotic class, but can persist in some cases. 
  • Humans are susceptible — While you can’t catch Lyme disease from your pet, you may be at risk if your pet has been exposed to an infected tick.
  • Lyme disease can be prevented — Ticks must remain attached for at least 12 hours for transmission to occur, so ensure you check your pet thoroughly after being outside and remove any ticks as soon as possible. In addition, you should protect your pet with year-round flea and tick prevention medication. A Lyme vaccine is available for dogs, and you should ask our veterinary professionals if your dog would benefit. 

Parasitic diseases are concerning, but you can take steps to decrease your pet’s risk. If your pet needs a heartworm test or parasite prevention medication, contact our team at Memorial Villages Animal Hospital, so we can ensure they remain parasite-free.