Parasitic diseases are very common among dogs. Even if you make sure your pet doesn’t eat anything suspicious during walks and give it properly prepared food, the chance that it will become infected with parasites may still be high. All he needs to do is lick his paws, chew his shoes, or drink water from a puddle after a walk. Invasive forms of parasites are constantly present in the environment and it doesn’t take much for them to get into the dog’s body. What are the most common dog worms? How to prevent infection?
Parasites in dogs – routes of infection
The parasites most often diagnosed in dogs are roundworms, tapeworms, hookworms, and giardia, as well as whipworms, lungworms, heartworms, and coccidia. Depending on their type, the routes of invasion vary. Dogs are often infected by food, eating eggs, larvae, or other invasive forms of parasites – they are common in the environment and may be present in raw meat from an unverified source, carrion, or in the feces of other animals. In the case of hookworm, infection can also occur through the skin (usually the pads of the paws), heartworms are transmitted by mosquitoes, and lungworms are transmitted by snails. Additionally, puppies can become infected with some parasites directly from their mother, during the fetal period, or by suckling milk.
Worms in dogs – symptoms
The most common symptoms of parasitic diseases are:
- Losing weight despite a large appetite
- Dullness of the coat
In some cases, nervous system symptoms such as dementia and even convulsions may occur. If your dog has been attacked by lungworm or heartworm, you can expect coughing, shortness of breath, blood clotting disorders and exercise intolerance. The dog may even die suddenly.
Diagnostics of parasitic diseases in dogs
To identify a parasitic disease, the veterinarian usually orders a stool test, and if lung and heartworms are suspected, he or she will take a blood sample. Sometimes the diagnosis is obvious – when the infestation is very large, you can see worms in the dog’s poop, and sometimes even in vomit. The stool sample for testing must be of appropriate size. It often has to be collected for several days because it happens that eggs or cysts cannot be found in a single sample because they are not excreted in the feces constantly, but cyclically. It may also be related to the development cycle of a given parasite. Therefore, most often the veterinarian asks for stool samples from 3 different days.
Selected types of parasites in dogs
Glisty (Toxocara canis)
They are roundworms. They live in the dog’s small intestine, where they breed and lay eggs, which are released into the environment along with the feces. Once the eggs enter the dog’s digestive tract, they hatch into larvae. They then migrate to the lungs, causing cough (a characteristic symptom of ascariasis). Then, together with the expectorated secretions, they are swallowed and develop into an adult form, capable of reproducing and laying further eggs.
Various species of tapeworms can be found in dogs. The most common of them are:
- Dog tapeworm (Canine pygidium)
- Multilocular tapeworm (Echinococcus multilocularis)
- Hydatid tapeworm (Echinococcus granulosus)
- Tapeworms of the genus Taenia
Even though they all belong to the group of flatworms, the routes of infection and the symptoms may vary. The dog tapeworm is transmitted by fleas and dog lice. Dogs can become infected with multilocular tapeworms by eating carrion or hunting rodents. Echinococcosis tapeworm may be present in raw pork and lamb from an uncertain source. Tapeworm eggs are also present in the feces of infected dogs and other animals. In case of infection with a tapeworm of the genus Taenia A characteristic symptom is the so-called “sledding”, i.e. the dog rubbing its hindquarters on the ground. This is because tapeworm segments released through the anus can cause itching in this area of the body.
These types of symptoms may also occur with problems with the dog’s perianal glands. Here I refer you to the article “Clogged perianal glands in dogs – how to deal with them?”.
Hookworms belong to the group of roundworms, just like roundworms. They live in the small intestine and feed on the blood of their host, causing anemia and destruction of the body.
Giardia intestinalis is another parasite that attacks dogs. It belongs to the dinoflagellate type and is a single-celled organism. It cannot be seen with the naked eye. By colonizing the dog’s digestive tract, it damages the intestinal walls, causing chronic or recurrent diarrhea, and sometimes the invasion is asymptomatic. Giardia can infect dogs, cats, and humans and is very difficult to combat. In my nutritional practice, unfortunately, it is one of the most common parasites among dogs. You can learn more about giardia from the article “Lamblia in Dogs – Everything You Need to Know about it”.
Dogs can become infected by eating snails. Adults reside in the bronchi, trachea, and pulmonary artery of the dog and cause coughing.
They came to Poland from Mediterranean countries and are an increasingly common problem. They are transmitted by mosquitoes, and adult individuals inhabit the pulmonary artery and heart of the dog. Their treatment is difficult and carries the risk of pulmonary embolism.
Appropriate medications are used to get rid of parasites. The procedure varies depending on the specific case. Due to the fact that dogs can easily become infected with worms present in the environment, it is most often recommended to deworm the dog every 3-6 months. However, please remember that deworming medications can be quite harmful to the intestines. Therefore, their preventive use may be problematic for chronically ill dogs, especially those with digestive system diseases, and for dogs with milder tummies. I definitely recommend checking the stool periodically, e.g. every 3 months, and then deworming it if necessary. This practice is a better example of prevention, where we avoid unnecessary problems with the digestive system.
In the case of puppies in the first six months of life, deworming drugs are administered 2 weeks after birth and then every month. If disturbing symptoms occur, it is worth performing a stool or blood test (in the case of lung and heartworms). The veterinarian adjusts the appropriate treatment to the specific case. Sometimes it lasts up to several weeks, and additionally, it may be necessary to thoroughly disinfect the dog’s living environment (e.g. washing the bedding at high temperatures or liming the yard).
Prevention of parasites in dogs
It is difficult to prevent parasitic diseases in dogs, but you can reduce the likelihood of infection by following a few rules on a daily basis:
- give your dog food from reliable sources
- do not choose raw meat of a lower category, but focus on the food category
- freezing meat can kill some parasites
- prevent your dog from eating carrion, rodents, and snails
- prevent drinking water from puddles
- clean up after your dog to reduce the risk of secondary infection and transmission of the disease to other animals
- examine your dog’s stool regularly