The Effects Worms in Dogs Can Have on the Pet's Mood

Refusing to leave his spot, even to play fetch, might be a warning sign.
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Worms make a harmful trail in your dog’s body. Some of them sop up all of the nutrients in poor Fido’s system, others damage vital organs and many kinds even affect his temperament. If you notice sudden changes in your four-legged chum’s mood, it’s time to get him to the vet to check for worms. If left untreated, a worm infestation can be fatal.

Low Energy

You know how it is to have a persistent belly ache. Suddenly even getting out of bed in the morning is completely out of the question. Your beloved friend experiences the same thing, except he doesn’t know why and he can’t tell you what’s wrong. If your hound is usually bouncing up and down and eager to play, but suddenly has no desire to leave his pillow, it could be a sign that worms are aggravating his tummy.

Lack of Appetite

For the most part, dogs are generally highly food-motivated. If they had thumbs and could walk to two feet, they’d probably do the dishes just for a shot at a morsel of your dinner. When worms are lurking around in Fido's body, though, he might feel full or his stomach simply feels too sore to eat, causing him to nap instead of eat. Because he can quickly become malnourished and dehydrated if his lack of appetite lasts for more than a day or two, you’ll need to get him in for an immediate checkup.

Sudden Snapping

Depending on the type of worm and the extent of the infestation, your cuddly pal could have sore spots on his abdomen. Or the worms may cause him to scratch profusely, leading to red and irritated patches on his skin. So when you go to pet him, as you always do, he could turn around and snap at you or pull away. It’s not that he doesn’t want your affection, it’s just that he’s uncomfortable and that spot you touched causes him pain.


Heartworm disease is one that has a big impact on your barking companion’s normally happy personality. In severe cases, not only can it make him overly fatigued, heartworm can also make your dog extremely nervous or anxious. Maybe he’s suddenly easily startled or growls at you for no apparent reason. Or he shreds an area of the rug if you’re not around to ease his anxiety. It’s not that you’re making him mad, it’s the pesky varmints lurking around in his system that are putting a damper on his personality.