Parasitic Infection of the Respiratory Tract in Cats


PetMD Editorial

Updated Aug. 24, 2022

Respiratory Parasites in Cats

Respiratory parasites can be worms, or insects such as maggots or mites that live in the respiratory system, either in the passages or in the blood vessels. The infestation might affect the upper respiratory tract, including the nose, throat, and windpipe, or the lower respiratory passage, including the bronchi and lungs.

Such parasites affect all of the host’s systems: the respiratory system, the cardiovascular system (the heart), the circulatory system, and the endocrine system (the liver and kidneys).

Animals that live in multiple pet households, and pets living in unsanitary conditions have a higher risk of transmission. Exposure to the infected feces of other animals that are carriers of the parasite can also make an animal more susceptible. This can include being in an environment such as a shelter or boarding facility, but your cat is also more at risk if it goes outdoors, as it has more opportunities to come into contact with other animals and their feces and urine.

These parasites often begin their life cycles in shellfish, crabs, lizards, and worms, spreading to other animals opportunistically.

Symptoms and Types

  • May show few or no signs
  • Sneezing
  • Runny nose
  • Bloody nose
  • Wheezing
  • Harsh lung sounds
  • Behavioral changes (brain migration of parasites)
  • Coma (brain migration of parasites)


  • Eating earthworms
  • Digging or sniffing around rodent burrows
  • Touching noses and/or other mucous membranes with infected cats or dogs
  • Being sneezed upon by an infected animal
  • Eating infected rodents
  • Eating infected martens and mink or being exposed to their feces
  • Eating infected birds
  • Eating sheep offal
  • Eating infected crayfish
  • Eating snails (uncooked)
  • Eating infected ants
  • Eating infected cockroaches (roundworms, hookworms)
  • Exposure to infected feces of other cats and dogs
  • Kittens can be infected prenatally and through their mother’s milk while nursing if the mother is infected


You will need to give a thorough history of your cat's health and recent activities, including recent history of boardings, outings, and experiences with other animals or with pests. Your veterinarian will then perform a complete physical exam on your cat. Standard laboratory work will include a blood chemical profile, a complete blood count, an electrolyte panel and a urinalysis in order to determine the exact origin of the symptoms. A differential diagnosis may find parasites, but it may also find a bacterial respiratory infection.

Your veterinarian will specifically examine your cat's urine and feces for parasite eggs or pieces of parasites. In feces, these are found by microscopically examining a solution of your cat's feces. A sample of sputum (cough discharge) can also be microscopically examined for parasite eggs.

X-ray imaging of the lungs is crucial for visualizing abnormal lung changes that may be indicative of a parasitic infestation. A rhinoscopy or bronchoscopy (direct visualization of the nose and bronchioles with a small camera) is an even better way to look for respiratory parasites.


Cats with respiratory parasites are usually treated on an outpatient basis with dewormers. Anti-inflammatory agents are also given to patients to decrease their body’s negative immune reaction to so many dead parasites. Some types of parasites can only be removed surgically one at a time.

If your cat is having trouble breathing, it should be hospitalized and given oxygen therapy until the parasite infestation has been resolved.

Living and Management

Your veterinarian will schedule follow-up appointments to examine your cat's respiratory passages with a bronchoscope and to reexamine fecal and urine samples for parasite eggs. Preventing your cat from eating insects, rodents, and wild animals is the best way of protecting your cat against parasite infections. Also, avoiding contact with unknown cats and dogs, or even separating your own pets (if you have others) when they appear to be ill are some ways in which you can prevent or mitigate a parasitic infection.

Most animals recover well from respiratory parasites, unless the infection has been chronic (long term). If parasites have migrated to the brain, causing your pet to show symptoms of neurological impairment, a cure will not be possible.

If you suspect that your cat is infected with parasites, schedule an appointment with your veterinarian as soon as possible. If your cat has already begun to show symptoms of neurological change or degeneration, call your veterinarian for an emergency appointment.

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