Internal parasites (worms) are a frequent problem in dogs. Almost all puppies are already infected with roundworm while still in the womb or contract the infection immediately after birth through the mother's milk (roundworm, hookworm). Moreover, dogs of all ages are constantly exposed to potentially harmful parasites through soil in the (back) garden and parks contaminated with infectious worm eggs or larvae or through mosquito bites, which can transmit heartworm infection (not in the Netherlands). Although some of these parasites are extremely dangerous, they can be easily controlled which can prevent disease.
Why worms are a problem
Heartworms are life-threatening and are one of the most dangerous parasites, but hookworms, roundworms, whipworms and tapeworms can also seriously affect a dog's health and well-being. Some worms can also be a public health hazard.
How can you examine your pet?
It is best to have your pet examined for worms. This can be done with a fecal examination. Almost all puppies have parasites. Therefore, it is essential to deworm every puppy and ensure constant prevention throughout its life.
Treating and preventing worms
Since almost all puppies are already infected at birth or become so immediately after birth, and they are constantly re-infected through mother's milk or by the environment, it is important to start worm-killing treatment in the very first weeks of life and to treat them often thereafter as well.
It is best to deworm bi-weekly from the time you take your puppy into your home until the puppy is 2 months old (i.e. 2, 4, 6, 8 weeks of age). Then deworm monthly until the puppy is 6 months. For the rest of its life, the recommendation is then to continue deworming every 3 months. It has been shown with research that more than 25% of parks and 60% of sandpits in a large city are infested with roundworms.
If you have a litter of puppies at home, it is important to treat the females at the same time. This will prevent puppies from developing the disease and excreting worm eggs through their faeces, thus preventing the environment from becoming infected.
Because of the wide spread of worms and the ease of infection, adult dogs should also be treated regularly (at least four times a year). Many drugs are available to treat and control worms. Some of them work against all common dog worms and thus provide complete protection for your pet.
Make sure you give your pet the drug that best meets his and your needs in terms of ease of use, effectiveness and safety (especially when treating young puppies).
Roundworms, also known as ascarids, are most common in dogs and cats. The adult worms are found in the intestines where they live off intestinal contents. In appearance, they resemble spaghetti: they are 2-3 mm thick and up to 20 cm long.
The life cycle of the roundworm
Adult roundworms live in the small intestine of dogs, where they lay up to 80,000 eggs a day. These eggs get into the environment via the dog's faeces, and within a few weeks an infectious larva develops in them.
When a dog swallows the infectious eggs, they hatch in its stomach. The larvae then penetrate the stomach wall and start migrating to various organs, before returning to the intestinal system and developing into adult worms that lay eggs. Some larvae do not return to the intestines: they remain encapsulated in the various organs until a stimulus, such as pregnancy, reactivates them and causes them to migrate again and develop into adult worms in the intestines.
Roundworms are especially harmful to puppies where the migrating larvae can cause liver, lung and brain damage. The presence of adult worms in the intestines leads to intestinal inflammation, which in turn has all kinds of effects on digestion, development and growth.
Heartworms are the most life-threatening dog worms, as they settle in the dog's heart and pulmonary arteries where they cause failure of heart function and eventually death. Adult worms are 10 to 30 cm long and about 1 mm in diameter.
Transmission and life cycle
Heartworms are transmitted by mosquitoes. When an infected mosquito bites a dog, it transmits the worm's larvae, which then migrate through the body until they reach their final destination (heart and pulmonary arteries) in about 3-4 months; there, they grow into adult worms (microfilariae) within another 3 months and start producing larvae (microfilariae) that can survive in the bloodstream for about 2 years When a mosquito bites an infected dog, it picks up these larvae and can thus pass on the infection to other dogs.
Over time, the presence of adult worms in the heart and pulmonary arteries causes inflammation and thickening of the wall of the veins, leading to an increase in blood pressure and greater effort by the heart to pump blood through them. As a result, the dog's heart function may begin to fail, eventually leading to death. The dog usually does not show clinical signs until the disease has reached a very severe stage (usually 3 to 5 years after infection). Initial signs consist of occasional coughing and fatigue; later, the cough becomes chronic and this is accompanied by labored breathing - especially during and after exercise -, mild anaemia and lethargy. In advanced cases, the dog may even collapse after only mild physical exercise. Most dogs eventually develop congestive heart failure.
Treating heartworm infection
Treating a heartworm infection is a long and risky process. Both dying heartworms and their larvae can lead to shock and embolism. During treatment, dogs should be strictly monitored for side effects and their activity restricted for a few weeks. Moreover - in advanced cases - their health does not recover, even after effective treatment. For all these reasons, it will now be clear why prevention is so important.
Unlike treatment, heartworm prevention is safe, easy and effective. Preventive agents are usually administered monthly, starting within one month of the start of the mosquito season (or exposure to a possible infection, for example when travelling to countries with heartworm) until one month after the end of the exposure. You can also choose to tackle any infestation with proper deworming if you enter an area with heartworm with your dog. You can collect deworming tablets for this from us.