Trust between friends can take years to build and only one careless mistake to destroy.

One dog-sitter’s trust quickly turned to regret when she realized agreeing to watch her friend’s dog would result in a gnarly flea infestation.

What’s worse, her friend appeared to know about the fleas all along.

You’ll want to read on for this one.

AITA for telling my friend to end their 10 day trip and come get their dog after I found out their dog had fleas?

I am babysitting a dog for my now ex-friend J — the dog is a husky. I love dogs, have two myself, and we have three total in the house.

When J asked over a month ago, I said yes as long as the dog was up to date on everything — shots, prevention, etc.

She tried to make extra sure that everything was covered on this front.

He said yes, he was sure.

Throughout the month, I asked repeatedly just to make sure. He swore up and down his dog was good to go.

This was really important to her for several reasons.

This is a huge deal for my house.

My own dogs are up to date, but I have a cat in the house that cannot be medicated. Our family cat has severe medical issues. We’re sure she’s only alive by sheer spite at this point.

But it didn’t take long for her worst fears to be realized.

So, I have this dog for less than 48 hours and find an adult flea.

No big deal — he came from a wooded area. If he’s on the proper meds, the flea bites and dies, like with my dogs. Cool.

Then I found more. I found eggs. I found live teenagers.

I have since medicated the dog and bathed him three times in flea shampoo. Which is hard — he hates it.

However, when she takes the dog to the vet, she discovers her friend hasn’t been completely honest with her.

J has called his vet for the meds, so I got to go pick them up for him.

But I asked the front desk when his last dose was, and she said three months ago. He’s been off medication for two months.

She can hardly contain her anger at this point, so she gives her friend an ultimatum.

I’m furious at this point and tell him he has 24 hours to find another place for the dog or come get it, trying to be gracious.

He argues with me and tells me he has no one, and has subsequently spent all of his money and can’t get home right now.

AITA for standing my ground?

A lie by omission is still a lie.

Redditors chime in with their thoughts.

This user thinks she has every right to be furious with her friend.

This commenter has two pieces of advice: One about the fleas, and one about the friend.

This commenter knows firsthand just how difficult it is to get rid of fleas.

Perhaps this was all a misunderstanding?

Finding the fleas was upsetting, but so was the knowledge that her friend knowingly withheld information from her.

She thought she was helping a friend in need, but all she got in return was a flea infestation and a hard lesson about trust.

If you thought that was an interesting story, check this one out about a man who created a points system for his inheritance, and a family friend ends up getting almost all of it.