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Park Worm (Spirocerca Lupi)

From an article by Dr. Doron Neri

Translated by Danna Brouner

The Park Worm is a fatal and widespread disease that is caused by the Spirocerca Lupi worm. The disease most commonly appears in dogs, but can also be found in other mammals. However, it is important to note that the disease cannot be spread to humans.

A study recently conducted at the Hebrew university in Jerusalem showed that despite the rising awareness of the disease in Israel, the disease is still widespread, its geographical spread having risen in the past couple of years. Today it has spread to the entire country and is one of the most common causes of death in canines living in Israel.

The Worm Life Span and the Process of Infection:

            The eggs of the worm are secreted into the feces of an infected dog. Dung beetles then eat the eggs and the young worms hatch, feeding off of the dog’s feces and residing in the intestines of the dung beetle. Dogs eat the beetles carrying the young worms while strolling outdoors. In the dog’s stomach, the worms are released and they proceed to penetrate the blood vessels and begin their journey through the dog’s body: First the worms breach the aorta and from there travel to the esophagus (the tube in the throat used for swallowing food). The worms settle in the membrane of the esophagus, and as a defense mechanism, the dog’s body surrounds the worms with a tissue response called a granuloma. This growth sticks out into the esophagus and the worms finish their growth cycle. At a later stage, the mature worms lay eggs in the esophagus. Those eggs travel through the dog’s digestive system and end up in the canine’s feces, completing the infection cycle.

            Dogs become infected by eating trash, animal feces, or pieces of food that contains dung beetles. The chance of developing an infection depends on the beetle, therefore the infection isn’t limited to a specific place and is likely to occur in a public garden, on the street, in a backyard, or in any other place where there is vegetation or dirt.

Symptoms of the Disease in dogs:

            There are two types of Park worm. The similarity in both types is that when they appear- it means that the disease is already in a late developing stage. At that point, the treatment can be problematic, and sometimes impossible:

1)      Vomiting- This is the most common symptom for the disease. The vomiting is caused by the granulomas that block the esophagus and make it difficult for the dog to swallow food. A common complaint dog owners will say is that their dog eats and vomits, then continues to eat and vomits some more. The dog is attempting to swallow the food but the granuloma blocking it is making him vomit it back up. But the dog hungry, so it will continue trying to eat.

2)      Sudden Death of the Canine- A less common symptom, a dog owner can be walking their dog when suddenly the dog collapses and dies. The worms in the blood vessels weakening the membranes until they eventually tear. The tear leads to massive internal bleeding with causes the sudden death of the dog.

3)      Paralysis and other Nerve Problems- In recent years there has been some reports about a third type of park worm. Worms in the spinal canal cause paralysis and nerve problems.

Other symptoms that might appear: Diarrhea, difficulty swallowing, difficulty breathing and coughing, weakness and weight loss, lung infection, and more.

It is important to state that in some cases the granuloma can become cancerous, and develop into a very progressive state of cancer.

Diagnosis:

            The Diagnosis is given based on the symptoms that the dog displays, an x-ray that can show a growth (granuloma) in the chest, an endoscopy (in which an optic fiber is inserted into the esophagus to better see the granuloma), and a feces check in order to identify worm eggs.

Treatment and Prevention:

            Since this is a fatal disease, when symptoms appear in its very late stages and it is almost impossible to treat it then, the way to withstand the disease is through prevention.

o   It is important to make sure that the dog does not eat anything outside (grass, pieces of food, or canine feces, etc), since this is the way to get infected.

o   Walking the dog with a leash only while supervising at all times. If the dog has a tendency to eat a lot on walks, a muzzle is advised.

o   Picking up canine feces and dispose it waste bin is another way to avoid a dog eating the waste containing beetles and worm eggs.

            Aggressive Periodic Treatment Using a Chemical that Kills Spirocecra Worms- This treatment is given by an injection by the veterinarian every three months. The injection is not a vaccination, and it lacks any ability to prevent future infections. It is a chemical that destroys worms that are present in the dog’s body at the time of the injection. The dog can be infected just days after receiving the injection, so it is important to continuously receive the injections on time.

            Dogs from the Collie breed (Collie, Border Collie, and mutts from their breeds) are likely to have a genetic mutation that makes them allergic to the chemical inside of the injection against the worms. For dogs of this breed, a genetic test is advised to determine if the dog is allergic to the chemical or not. This simple blood test is sent to a lab, and only needs to be done once in the dog’s life.

            In some studies, a type of ampoule against fleas called “Revolution” or "advocate" assists in killing the park worms. It is advised to use it in dogs that tend to eat waste In addition to periodic Ivomec/Duramectin injections

Treatment After Infection

            If the dog has already contracted the disease, the treatment is a long set of injections given to the dog every two weeks while undergoing multiple tests like x-rays, endoscopies, and feces checks. It is important to state that in many cases the disease is identified in its later stages, and by that time it is impossible to treat the dog. A surgical solution is extremely dangerous and complicated, because it involves opening the chest and removing part of the esophagus and the chances of success are very slim. This type of treatments can be very expensive.

Park Worms is a very widespread and fatal disease, but in most cases the prevention is simple: an injection that is given every three months by a veterinarian. Be precise about receiving injections at the appointed times!

For any questions please phone us. Dr. Doron Neri veterinary surgeon, Ramat Hasharon- Herzeliya veterinary center

03-5403368