Parasitic Infection of the Respiratory Tract in Dogs

The parasitic invasion of areas in the respiratory tract of your dog can mean a mild infection with symptoms of coughing and sneezing, ranging to wheezing and signs of intense respiratory distress. Illnesses like bronchitis, pneumonia and rhinitis are common occurrences when parasites migrate within your pet’s pharynx or bronchi. Further migration throughout other systems can accompany the infection which is why treatment is so important. If your pet has symptoms of a respiratory illness and has regular access to the outdoors where he has exposure to carriers such as rodents or snails, a visit to the veterinary clinic is warranted. Treatment, and the successful resolution of the problem will vary depending on the type of parasite.

Invasion by parasite can cause infection in the respiratory tract in canines in areas such as the trachea, nasal cavity, and lungs. Depending on the severity and location of the infection, complications can become serious if the infection is left untreated.

With some types of parasitic infection, dogs can be asymptomatic. Other instances of the condition may present with mild signs while others show serious symptoms leading up to respiratory distress. Your pet may exhibit some of the signs below.

• Coughing (can be dry, chronic, deep, or intermittent)
• Wheezing
• Weight loss
• Increased breathing rate
• Sneezing
• Nasal discharge
• Weakness
• Vomiting
• Lethargy
• Regurgitation
• Aspiration of food or stomach contents
• Worms present in feces 

Types

There are a myriad of parasites that can occupy the airways and respiratory systems of our pets. A few of the well documented types are listed here.

Toxocara canis

• There are 4 modes of infection, one of them being the ingestion of rodent or birds
• The larvae can migrate to many areas including the brain, liver, and lungs

C. aerophila

• The parasite eggs are consumed from drinking contaminated water
• The larvae move throughout the circulatory system to the sinuses, bronchi, lungs, and trachea

Oslerus osleri

• Parasites can be passed through the saliva (for example an infected parent licking the pups)
• Larvae travel through the blood to the bronchi and lungs

Strongyloides spp.

• The 3rd parasitic stage invades the mouth and passes via the bloodstream into the lungs
• Can cause diarrhea and cracking of the skin of the footpads

Crenosoma vulpis

• The fox is the definitive host, while snails are the intermediate host
• The migration ends up in the lungs after passage through the visceral lymphatic or hepatic portal system

• Parasites can interfere with the function of the lungs, bronchial tubes, throat, trachea, sinuses, mouth, and nose
• Pets that have a lot of outdoor exposure and hunt for rodents and birds can easily ingest parasites
• Ingestion of sheep offal (butchered organs, etc.)
• Pups can become infected from the mother’s saliva
• Canines that eat crayfish, crabs, snails, and slugs can ingest parasites
• Lizards and frogs are also carriers
• Dogs who frequent fox inhabitants may pick up the parasites as the fox is a definitive host
• Eating contaminated food or drinking contaminated water can promote parasitic invasion
• Environments that are humid, moist, unsanitary, or overcrowded can be beneficial to parasitic abundance

One of the most common and prevalent signs of parasitic infection of the respiratory tract is coughing. The type and frequency of the cough can vary greatly. However, if you notice that your pet is coughing, no matter how intermittent, a veterinary visit is warranted as canines do not normally cough which is indicative that something may need to be investigated.

Your pet could have other signs of being unwell such as lethargy or loss of appetite, or he could be having instances of regurgitation. When you bring your dog to the clinic, be certain to tell the veterinarian the signs you have noticed in your pet as of late that have caused you to become concerned. Advise your veterinarian if your dog has been in a boarding kennel recently, or if your travels or day trips have taken you and your canine companion to areas where wildlife may be present.

Standard testing will be run such as urinalysis and complete blood count, and in the case of a suspected parasitic infection, a fecal analysis will definitely be done because many invasions show their presence with larvae in the feces (and larvae or adult parasitic forms are often in the vomitus if your pet is vomiting).

Depending on the symptoms, clinical signs, and history of your dog, the additional testing could include the following.

• Radiology
• Cytology of tracheal wash (inflammatory cells could be found)
• Scrapings from oral or intestinal mucosa for cytology
• A bronchoscopy could show nodules or lesions in areas like the trachea
• Bronchoalveolar lavage

The most common form of treatment for a parasitic invasion of the respiratory tract is through oral medication which will be administered from any length of time between a few days to a few months. Some of the medications utilized to eradicate the infection are oxfendazole, albendazole, thiabendazole, levamisole, and ivermectin. Prednisone has been used in addition in some cases where inflammation needs to be addressed. When there are parasitic nodules present, a bronchoscopy may be successful in removal.

Follow-up visits to the veterinary clinic will be necessary because frequent checking for the complete eradication of the parasite is key. It is essential to remove all signs of the infection in order to avoid further complications. Respiratory distress, secondary bronchitis and pneumonia, and even death have occurred because of parasites in the respiratory tract. Adherence to the instructions of your veterinarian, including completion of all medications is imperative. At home, ensure that your canine companion’s living space is clean and free of humidity and dampness. In the future, do not allow free roaming in order to avoid picking up a new parasitic infection via hunting, eating of spoiled food, and exposure to contaminated areas and wildlife.