The Most Common Intestinal Worms

The most common intestinal worms are not very dangerous for adult dogs but can be quite unpleasant. And they are becoming more common.

Many dogs get worms at some point in their lives and it is usually some type of roundworm. Puppies are particularly vulnerable and can be infected by the bitch already in the womb or later, through breast milk. But adult dogs are also affected. They either ingest eggs or larvae when they sniff at other dogs’ poop or via, for example, earthworms, insects, small rodents, or birds.

– The larvae then develop further in the dog and migrate to the lungs. The dog coughs up the larvae and swallows them again. Only then do they become adults and can begin to release eggs in the dog’s intestines, says veterinarian Hedvig Armerén.

That sounds pretty nasty. But how harmful is it really?

– Worms in the lungs can cause a cough or pneumonia that can become quite serious, especially in puppies. Mask in the stomach can lead to diarrhea in adult dogs, but it is often not so dangerous. For puppies, it is worse. Among other things, they are much more sensitive to the nutritional deficiencies that the worms cause and if there is a lot of worms, it can be life-threatening.
Many adult dogs are not affected at all by the roundworm, but a dog with a mild but prolonged cough and which seems alert and healthy in general may have had a worm in the lungs. Signs of worms in the intestines can be constipation, diarrhea, vomiting, and a bloated stomach. The dog can also lose weight and have poorer fur quality.

Tapeworm gives about the same symptoms as roundworm in the gut. The larvae develop in an intermediate host, which can be anything from small prey to fleas, raw fish, raw meat, and offal. The dog becomes infected when it eats an infected animal.

Common to several of the tapeworm species is that they can have both animals and humans as the main host. It’s disgusting, absolutely, but fortunately, the worms are not dangerous and there are effective remedies that kill them.

Now you might think that it would be good if you could treat your dog preventively so that it does not get worms at all. And this was also done before, but since the worms can become resistant to the agents, the veterinarians stopped recommending regular deworming for all dogs.

– A few years ago, studies showed that worms were not so common in dogs in cities. But my opinion is that the worms are now increasing, probably because we stopped deworming and because many dogs live so close to each other. Stockholm, for example, has become very dog-dense and when everyone rests their dogs on the same resting yards, goes to the same dog daycare, and stays at the same dog cafes, the worms spread, says Hedvig Armerén.

A tapeworm map that is not harmful to dogs but which is unfortunately far from harmless to us humans is the fox dwarf tapeworm. It did not exist in Sweden for a long time, but a few years ago the first case appeared here as well. The dog ingests the worm when it eats an infected small rodent but does not get sick itself. For a person who swallows eggs, which can be found on mushrooms and berries, for example, the situation is completely different.

– The eggs hatch in the intestine and the larvae migrate to the liver where they form large cysts that destroy the liver and displace healthy tissue, says Hedvig Armerén.
A liver transplant is often required for an infected person to survive and then lifelong treatment.

Affected dogs can be dewormed.

Another nasty worm that has appeared in Sweden in recent years is the French heartworm. It is found in several places in Europe and has also established itself in Denmark. Where the worm is common, the dogs are under constant preventive treatment.

– The heartworm is deadly and lives in the heart and lungs’ blood vessels in dogs. Common symptoms are that the dog has a prolonged cough, difficulty breathing, lean, and becomes tired. When the infection worsens, the worms can cause blood clots and bleeding that are so serious that they lead to death, says Hedvig Armerén.

If you go abroad with your dog, or for that matter import a dog from southern Europe, it is good to know about Dirofilaria, heartworm that is similar to the French but is even more deadly. If you take your dog to a country where the worm is located, make sure it gets heartworm prophylaxis before you go.
– And if you plan to take care of a Spanish street dog, for example, the first test with a blood test if the dog has the infection because then it can never get rid of it!

Dirofilaria is spread via mosquitoes, but so far no dogs have been infected on site in Sweden. Although there are no guarantees that our Swedish insects do not spread the disease, therefore avoid bringing an infected dog here.

It can be difficult to know if a dog has a worm. But some symptoms can be:

• Mild but prolonged cough.
• Digestive problems.
• Swollen stomach.
• Weight loss despite a good appetite.
• Matted fur.
• Visible worm eggs in the dog’s poop.