Diagnosing Parasites in Dogs

Parasites are organisms that require the help of a host animal in order to survive. Some of the most common parasites in dogs include fleas, mites, ticks and worms. Each of these organisms comes into contact with the host and relies upon that host for shelter and sustenance. Most canine parasites feed off of the blood of the host animal. Parasites may cause a variety of mild to serious effects, and it's important to be aware of the types that may attack your pet, as well as the symptoms that an infection presents and the treatment options. In order to make a successful diagnosis, be aware of the basic information about canine parasites.

Parasites of the Skin and Hair

Canine parasites fall into one of two categories: internal- or external-dwelling. Fleas, ticks and mites all live on the surface of your pet's skin and hair. They typically feed off of your pet by consuming skin or, more often, biting the skin and sucking blood. Generally, external canine parasites present one or more of the following symptoms:

  • Itchiness (accompanied by unusual scratching or other attention)
  • Redness, irritation and inflammation (either localized in a particular area or spread throughout the body)
  • Sores, bites or lesions
  • Change in coat texture, color or shine
  • Loss of hair

Different types of canine skin parasites result in a variety of different symptoms. In order to properly diagnose the parasitic infestation, it's necessary to take your pet to a veterinarian for further examination. The vet will conduct a physical examination to watch for visible signs of parasitic infestation, and may also take a skin scraping or sample for further testing. The skin scraping allows the veterinarian to examine a portion of the outer layer of your pet's skin under a microscope, which is often helpful in determining the type of parasite causing the symptoms.

Internal Canine Parasites

Internal canine parasites live within the dog's body. Hookworms, roundworms and tapeworms are all common internal parasites. Internal parasites may lead to anemia, weakness and even death in some cases, and it's crucial that you be aware of the symptoms of internal parasitic infestation and react promptly upon detection.

Look for the following symptoms of an internal canine parasite:

  • Itchiness, particularly surrounding the anus
  • Weight loss
  • Distended abdomen
  • Lethargy
  • Depression
  • Visible eggs or worms in the stool

Worms and other internal parasites are passed in the stool. In some cases, these organisms are large enough that they are visible in your pet's stool. Others, like hookworms, are so small that they are invisible to the naked eye. As such, do not assume that your pet is free of internal parasites if you do not detect them in or around his stool. If he displays any of the above symptoms, have him examined by a veterinarian immediately.

A diagnosis of internal parasites typically requires a full physical examination and stool sample. Using a microscope, your veterinarian will attempt to identify worms and eggs in the stool. Additional blood testing may be necessary in some cases.

Treating Canine Parasites

Proper treatment of canine parasites depends upon the type and severity of the infestation. External parasites may be controlled with topical medicine, flea collars and other repellents. Internal parasites typically require a medicinal treatment. Because a single treatment of an oral or injection-based parasite medicine will only eradicate adult parasites, it is usually necessary to repeat the treatment program multiple times in order to ensure that the infestation is accounted for.