Is it possible for a cat to have parasites without diarrhea? Do parasites always show up on a fecal test?

[theorangecat]

Just got blood work done, and my cat's protein is low. He seems to have lost some muscle mass over the past six months. I'm waiting on my vet to get back to me with next steps. She thinks it might be liver or gastro related. However, based on my googling, it seems like parasites might also be an option. My cat always has solid stools except for when he gets new food. My vet seemed to think this indicates that he doesn't have parasites, but I want to be absolutely, absolutely sure that it's not. He's an indoor cat, but he occasionally goes out in the backyard on a leash.

Is it possible for him to have some sort of parasite/worm/whatever without accompanying loose stools? Will parasites always show up on a run-of-the-mill fecal test?

 

[Sajast]

It is technically possible and the way fecal float tests work is by looking for eggs. If a female worm isn’t shedding eggs at the time of the test then you will get a false negative. However, if Cat is extremely low risk for parasites the vet will lean toward more likely scenarios. Also, many cats will have gastric upset if you abruptly switch their food. So if you’re switching food and they get diarrhea - that’s not due to parasites, that’s due to switching their food too quickly. If it makes you feel better you can ask for a a course of panacur.

 

[Caspers Human]

Yes, it is possible for a cat to have parasites without getting the runs or even showing external symptoms.

No, parasites are not always detected by a simple test for parasites.

I have had two cats that got worms. Neither of them showed signs of infestation until they either barfed up worms or I saw worms in the cat's stool.

There are two general types of test for worms. One is, basically, by looking at a sample under a microscope. Sometimes parasites or eggs show up in the microscope. Other times, they are not visible or else the doctor or technician can miss the signs because they are often difficult to detect. The other is a full-on lab test where they look for DNA or other stuff. It's a better test but it's more expensive and it takes longer. That's why the microscope method is still so popular. It's cheaper, easier and still works in most cases.

Yes, a cat can get worms even if they are 100% indoor. Both of my cats that got worms were indoor. One got it from catching a mouse that was infested. The other, Casper, barfed up a load of worms shortly after we adopted him. Even thought the cat rescue people we got him from said that he had been checked and had a clean bill of health, it's still possible that they (the vet) either missed the signs or else they did find worms and treated him but the medicine didn't kill all the parasites. This is fairly common. Sometimes it takes two or even three tries to kill all the parasites. Giardia is notoriously difficult to eradicate.

If your cat has a problem that might be attributed to paraistes it is smart to perform tests. As with many things, it's better to rule out simple causes than to order expensive tests and treatments before you are sure what's happening.