Symptoms in dogs with worms can vary considerably depending upon the type of worm, the overall health of the dog and a variety of other factors. Worms can infect various parts of your pet's body, from his intestinal tract and other digestive processes to his heart and other organs. They range from a mild or moderate nuisance to an immediate and potentially lethal threat. Because of this, and because it's often difficult to tell how serious your pet's worm condition is based on his symptoms, it's crucial that you take him to the vet for proper diagnosis as quickly as possible after you recognize his symptoms.
Diarrhea
One of the most basic symptoms in dogs with worms is diarrhea. You may notice periodic diarrhea or, more likely, repeated and predictable diarrhea most every time that your pet evacuates his bowels. The diarrhea may be darkly colored or may even have visible eggs or small worms in it. Take note of the quality and consistency of your pet's bowel movements.
Change in Appetite
Dogs with worms may actually experience an increase in total appetite. The reason for this is that the worms which infect your pet's intestinal tract and digestive systems will actually be responsible for eating and stealing the nutrients from the foods that he eats. As a result, your pet will continue to eat but will not be satisfied and will demand more food. Watch out for signs that your pet continues to be hungry after eating, or if he begs for food only a short time after eating a meal.
Loss of Weight
Though your dog may continue to eat a huge quantity of food and may even eat more food than he normally would, it's possible that he'll actually lose weight if he has worms in his system. Again, the reason for this is that the worms in his body will be absorbing and stealing away the nutrients that he needs otherwise to help to keep his body strong and healthy.
Lethargy
Accompanying the loss of weight and the general lack of proper nutrition, a pet that is suffering from worms may appear to have a generally reduced energy level as a result of the worms in his system. This is common for dogs with all types of worms. Watch out for your pet not being willing to get up and run or play or even being reluctant to walk. Some dogs with worms will actually ignore their owners and may even display signs of aggression when their owners try to get them to be active once again.
If you notice these or any other symptoms of worms in your dog, it's important that you get him to a vet as quickly as possible. The reason for this is that worms can be potentially very harmful to your pet.