Intestinal parasites are very common in dogs and cats. In addition to causing disease in our pets, some of these parasites are also zoonotic, or capable of causing disease in humans. Contrary to popular belief, many intestinal parasites cannot be seen with the naked eye, so a yearly ‘fecal’ (microscopic examination of the feces) is recommended to diagnose intestinal parasite infections. Once intestinal parasites are diagnosed, appropriate treatment is instituted. Prevention of intestinal parasites is extremely important and is accomplished by using an appropriate heartworm preventative monthly.
Tapeworms
Scientific names of most common dog and cat tapeworms in West Central Florida include: Taenia taeniaeformis (cats), Dipylidium caninum (cats and dogs), Taenia pisiformis (dogs). Of these, Dipylidium, a tapeworm transmitted by fleas, is the most common.
Diagnosis: Tapeworms are usually diagnosed by visually detecting segments in feces. Dipylidium segments appear as single segments about 1/2- to 1/4-inch long and yellowish to pinkish-white in color. Many people say they look like rice, and when they dry up they look very much like yellow rice. Dipylidium segments may be seen on feces, on the hair in the pet’s perineal area, or on the surface where the pet has been resting.
Less commonly, your pet might contract other types of tapeworms. These are usually passed as tape-like strips of segments joined together.
Clinical signs: most animals are asymptomatic. Weight loss, anal itch, vomiting, diarrhea, are symptoms of tapeworms. They can cause intestinal obstruction in rare cases.
Mode of transmission: For Dipylidium, oral ingestion of infected fleas is the only means of infecting dogs and cats. Any pet who has Dipylidium tapeworms also has, or has had, fleas. Other tapeworms are contracted by ingesting the meat of infected small rodents, livestock, or fish.
Tapeworms cannot be directly transmitted to other pets. All tapeworms pass from a host species (dog, cat, human, or other animal) to an intermediate host (flea, fish, rodent, etc.). They must spend time in the body of the intermediate host before they become ineffective to the host animal (dogs and cats, for instance).
Treatment: Praziquantel injection or tablets/capsules.
Prevention: Your pet may require a monthly flea preventive for Diylidium. It’s also important for your pet to avoid infected animals. Keep cats indoors to prevent hunting. Do not feed animals raw meat, especially sheep and wild ruminants.
Zoonotic disease: Dipylidium caninum can be transmitted to humans if a human orally ingests an infected flea. Humans cannot be directly infected by pets.
Echinococcus granulosus is a tapeworm that dogs become infected with after eating an infected sheep or wild ruminant. This particular tapeworm can cause serious disease in humans. This type of tapeworm is extremely rare in our area, and your dog is not at risk unless you feed him infected sheep or wild ruminant meat.
Information about human Echinococcus infections from the CDC
Roundworms
Species affected: dogs and cats
Scientific names: Toxocara canis (dogs), Toxacaris leonina (dogs and cats), Toxocara cati (cats)
Clinical signs: none in early infections
Cats: stunted growth, damage to tissues due to migrating larvae, diarrhea, vomiting, pot-bellied appearance, death
Dogs: stunted growth, diarrhea, vomiting, pot-bellied appearance, liver and lung damage due to migrating larvae, death
Mode of transmission: oral ingestion of eggs from environment, oral ingestion of larvae present in an intermediate host (ie. rodents), transmission of larvae from dam to young through the placenta (dogs only) and milk (dogs and cats)
Diagonsis: eggs in fecal examination. Because parasites do not consistently shed eggs to be found under the microscope, deworming of all puppies and kittens, and the use of monthly heartworm preventatives, is recommended. Our recommended heartworm preventatives are Trifexis or Heartgard for dogs and Revolution for cats.
Treatment: fenbendazole or pyrantel pamoate, various other dewormers, and supportive care
All puppies and kittens should be dewormed for roundworms prevention. Roundworm eggs are very resistant in the environment.
• Pick up feces immediately with a plastic bag and discard it into trashcan until infection is resolved
• Wash hands well after handling feces
• Make sure all pets are screened yearly for roundworms and treated if infected
• Administering a monthly heartworm preventative like Trifexis or Heartgard (dogs) or Revolution (cats) will prevent pets from becoming infected with roundworms
• A 1% bleach solution (3 cups bleach per gallon of water) will disinfect surfaces
• Confine cats indoors
• Prevent coprophagia (ingestion of feces)
• Do not allow pets to lick human faces
Zoonotic disease: Human toxocarosis (visceral larva migrans)
• Results from oral ingestion of eggs
• Primarily affects children and immunocompromised adults
• Larva migrate through the lungs, liver, kidneys, brain, and eyes, leading to inflammation and organ damage
• A leading cause of blindness in young children
Information about human roundworm infections from the CDC
Hookworms
Species affected: dogs and cats
Scientific names: Ancylostoma caninum and Uncinaria stenocephala (dogs), Ancylostoma tubaeformae (cats)
Clinical signs: none may be noted in early stages of infection
Cats: weight loss, diarrhea, vomiting, anemia, poor hair coat, pulmonary lesions, dermatitis, death
Dogs: anemia, diarrhea, vomiting, weakness, poor growth, death
Mode of transmission: oral ingestion of eggs from environment, penetration of skin by larvae, larvae pass from dam to young through milk
Diagnosis: eggs in fecal examination. Because parasites do not consistently shed eggs to be found under the microscope, deworming of all puppies and kittens, and the use of monthly heartworm preventatives, is recommended. Our recommended heartworm preventatives are Trifexis and Heartgard for dogs and Revolution for cats.
Treatment: fenbendazole or pyrantel pamoate; supportive care
All puppies and kittens should be dewormed for hookworms.
Prevention: Hookworm eggs are very resistant in the environment
• Pick up feces immediately with a plastic bag and discard it in the trashcan until infection is resolved
• Wash hands well after handling feces
• Make sure all pets are screened yearly for hookworms and treated if infected
• Administering monthly heartworm preventive like Trifexis or Heartgard (dogs) or Revolution (cats) will help prevent pets from becoming infected with hookworms
• Wear gloves when gardening and avoid going barefoot
• A 1% bleach solution (3 cups bleach per gallon of water) will disinfect surfaces
• Prevent coprophagia (ingestion of feces)
• Do not allow pets to lick human faces
Zoonotic disease: “creeping eruption” (human cutaneous larva migrans)
• A linear tortuous red itchy eruption on human skin caused when hookworm larvae penetrate the skin and migrate
• Very rarely eosinophilic enteritis can occur.
Information about human hookworm infection from the CDC
Whipworms
Species affected: dogs
Scientific name: Trichuris vulpis
Clinical signs: none may be noted in early stages of infection. In later stages of infection, intermittent diarrhea, weight loss and even death
Mode of transmission: oral ingestion of infected eggs in the environment
Diagnosis: eggs in fecal examination. These parasites often do not shed eggs that are detectable on fecal examination. For this reason, using a heartworm preventative like Trifexis, which is a suppressive for whipworms, is a good idea.
Treatment: fenbendazole; supportive care
Prevention: whipworm eggs are very resistant to disinfection so reinfection is common after treatment
• Pick up feces immediately with a plastic bag and discard into trashcan until infection is resolved
• Wash hands well after handling feces
• Administering Trifexis monthly will prevent reinfection even if eggs persist in the environment
• Preventing coprophagia (ingestion of feces)
Toxoplasmosis
Species: cats
Scientific name: Toxoplasma gondii
Mode of transmission:
• Ingestion of infective cysts from the environment
• Cats can also become infected by consuming cysts present in the tissues of any warm-blooded mammal
• Infection can be spread from dam to young via the placenta
• Cats shed infective oocysts for about 2 weeks after initial infection – after that time, the cat is unlikely to shed infective oocysts
Clinical signs: may be asymptomatic, diarrhea
Diagnosis: oocysts on fecal examination, various blood tests also available, can be diagnosed on biopsy of infected muscles but this is rarely performed
Treatment: clindamycin or sulfonamides; cats shedding infective cysts should be hospitalized until shedding stops (about 2 weeks)
Prevention:
• Keep cats indoors and prevent hunting
• Cook all meat (for both humans and cats) to 160 degrees F – freezing does not kill infective cysts
• Wear gloves when gardening
• Clean litter boxes regularly
• Wash produce well before consuming
Zoonotic disease: Toxoplasmosis
• Many infections are asymptomatic
• Signs include: fever, myalgia, swollen lymph nodes, decreased appetite, sore throat
• If a woman is infected with Toxoplamosis for the first time during pregnancy (first and second trimester), abortion, congenital abnormalities, and mental retardation may result
• Most cases of human toxoplasmosis result from ingesting undercooked meat, improperly washed produce, and gardening without gloves, not from cats
• Keeping cats indoors is key to prevention
• Pregnant women should not clean litter boxes
Information about human toxoplasmosis from the CDC
Coccidia
Species: dogs and cats
Scientific names: Isospora canis, Isospora ohioensis and Isospora burrowsi (dogs); Isospora felis and Isospora rivolta (cats)
Clinical signs: some animals asymptomatic, diarrhea, vomiting, abdominal pain, dehydration, and death
Mode of transmission: oral ingestion of oocysts
Diagnosis: oocysts on fecal examination
Treatment: sulfonamide drugs; supportive care
Prevention:
• Pick up feces immediately with a plastic bag and discard into trashcan until infection is resolved
• Wash hands well after handling feces
• Prevent coprophagia (ingestion of feces)
• Drying and sunlight are effective at killing infective cysts
• Chemical disinfectants have little effectiveness
Giardia
Species: dogs and cats
Scientific name: Giardia canis
Clinical signs: early infections may be asymptomatic, diarrhea
Diagnosis: organisms or cysts in fecal examination on fresh feces, more advanced testing available for special cases
Mode of transmission: oral ingestion of cysts
Treatment: metronidazole and/or fenbendazole; supportive care
Prevention:
• Pick up feces immediately with a plastic bag and discard into trashcan until infection is resolved
• Wash hands well after handling feces
• Prevent coprophagia (ingestion of feces)
• Disinfect surfaces with 1% bleach solution (3 cups bleach in 1 gallon water) or 2-5% Lysol solution
• Do not allow pets to lick human faces
Zoonotic disease: Giardiasis
• Many infections are asymptomatic, diarrhea may occur
• Humans rarely become infected with giardia from their pets
• Most human infections occur when camping and drinking contaminated water