Lungworms are one of those things vets learn about in parasitology. But cases are pretty rare, so the info was stored way back in the hidden files of my brain when I had a curious case of a cat who was not responding to treatment at my very first job out of vet school.

When he first came in, he had the typical upper respiratory “gunk” that we often see with stray cats. You know—crusty nose, crusty eyes, and sneezing. This guy was also coughing, so I assumed he had a secondary bacterial infection, sent him to his new home with antibiotics and went about the rest of my day.

He came back a week later, and his “gunk” had cleared, but his cough was still nagging. As I sat there racking my brain for answers, one of my favorite assistants asked, “Did you do a fecal test?” Now, Sandy (the assistant) was a cat rescuer extraordinaire, so she knew what she was talking about. All of a sudden, it clicked—lungworms!

What on earth is a lungworm?!

There are several species of lungworms, but they mostly act the same way. And yes, they are actually worms! They can infect both dogs and cats in, you got it, the lungs. And when they do, they cause respiratory signs like persistent coughing. Severe cases can progress to pneumonia.

Mission: transmission

Pets can get lungworms when they eat snails, slugs or earthworms (and sometimes when they eat things that eat snails, slugs or earthworms). The larvae from their tasty snack get through the gastrointestinal tract and migrate to the lungs. Female lungworms lay eggs in the lungs, and baby larvae travel up the airway before they’re swallowed. From there, they travel through your pet and end up in their feces, ready to infect the next snail who crawls around.

Occasionally, all of that coughing dislodges eggs from the lungs. They come up the trachea and end up getting swallowed with your pet’s sputum. That’s how we can sometimes see lungworm eggs in the fecal samples of infected pets.

Digging for lungworms

Fecal tests are the best way to diagnose lungworms in both dogs and cats, though a negative fecal doesn’t automatically rule out lungworm infection. Sometimes when patients fit the bill, but we can’t find direct evidence of lungworms, we just have to treat and note the patient’s response.

Be gone, you worms!

Treatment is easy—deworming is all it will take. It’s likely that your vet has a favorite dewormer for lungworms, and depending on the species, you’ll treat from a few days to a few weeks. After treatment is finished, your vet will want to recheck your pet’s stool to ensure that it’s in the clear. That’s it—easy, peasy!

Since that day a long time ago, I’ve seen many cases of lungworms. Each time I think about Sandy, who still works at that clinic, and still thanklessly rescuing stray cats. Thanks, Sandy.

Oct 11, 2016
Pet Health

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