When It’s More Than an Itch: Parasites That Mimic Other Pet Conditions

As veterinarians, parasitic infections are almost always on our list of possibilities when diagnosing our pet patients. Parasitic infections and uncommon pet parasites can sometimes look like other health conditions. The experts at Animal Medical Hospital & Urgent Care aren’t easily fooled, though, and parasites are not safe when we are on the case.

Hookworm Blues

Hookworms are a common intestinal parasite. Smaller than the roundworm, they are nearly invisible to the naked eye. 

Hookworms attach to the lining of the intestines and suck their host’s blood. They enter the body through the ingestion of fecal particles or through breaks in the skin. 

The biggest danger they pose is potential complications from blood loss. In severe cases, especially in puppies and kittens, this can lead to life-threatening anemia, weakness, and failure to thrive. 

Because of their effects on red blood cell levels, hookworm infections can mimic other conditions such as autoimmune hemolytic anemia, iron deficiency, or other causes of chronic lethargy. Infected pets may also develop diarrhea, weight loss, and a poor coat condition, which can be mistaken for nutritional deficiencies, inflammatory bowel disease, or other gastrointestinal disorders.

The Problem with Tapeworms

Tapeworm infections, though often less urgently dangerous than hookworms, can still cause significant health issues in dogs and cats. Tapeworm segments, which resemble small grains of rice, may be visible in the pet’s feces or in the fur under the tail.

There are various species of tapeworms, but they all survive by attaching to the walls of the intestines and absorbing nutrients from their host. This can lead to weight loss, poor coat quality, and digestive disturbances such as vomiting or diarrhea. 

Because tapeworm infections can cause gradual weight loss despite a normal or increased appetite, they can be mistaken for metabolic disorders, malabsorption syndromes, or even more serious conditions like cancer. Additionally, excessive licking or scooting due to irritation from the tapeworm segments may be misinterpreted as anal gland issues or allergies.

Lungworm in Pets

Lungworms are a less common parasite that are typically contracted through the ingestion of infected snails, slugs, or contaminated water sources. Lungworms in pets can be especially deceptive. Infection with this parasite looks very close to respiratory diseases like:

• Bronchitis
• Pneumonia
• Asthma

Lungworms reside in the lungs and airways, as their name suggests, and cause coughing, wheezing, difficulty breathing, and even respiratory distress. 

Some infected pets may also experience lethargy, weight loss, or a decreased appetite as seen in heart disease or other systemic illnesses, further complicating diagnosis.

Because the clinical signs can vary, lungworm infections can be overlooked or mistaken for more common respiratory conditions.

Toxoplasmosis in Cats

Toxoplasmosis is a parasitic infection seen  in cats that can mimic a variety of other diseases. The single celled organism can affect multiple organ systems, resembling other infections, neurological disorders, or systemic diseases. 

• Neurological Disorders — When toxoplasmosis affects the nervous system, symptoms like seizures, incoordination, muscle weakness, or behavioral changes can occur. These may be mistaken for diagnosis like epilepsy, brain tumors, or feline infectious peritonitis (FIP).  
• Respiratory Diseases — If toxoplasmosis affects the lungs, it can cause coughing, difficulty breathing, and pneumonia-like symptoms. This can be confused with feline asthma or other bacterial respiratory infections.  
• Liver Disease — Cats with hepatic toxoplasmosis may experience jaundice, vomiting, and lethargy. These symptoms are also seen in liver infections, toxicities, or hepatic lipidosis.  
• Gastrointestinal Issues — Toxoplasmosis can cause vomiting, diarrhea, and weight loss, symptoms commonly associated with inflammatory bowel disease, pancreatitis, and other systemic illness.  

In some cases, cats may have nonspecific signs like fever, loss of appetite, and lethargy, which could be mistaken for a wide variety of conditions. Because toxoplasmosis symptoms overlap with so many other diseases, diagnostic testing, including antibody blood tests and imaging, is essential for an accurate diagnosis.

Parasites in pets can be tricky business, but just knowing when and how to look for them gives our staff a leg up when it comes to getting your pet better. Please contact us if you have questions or concerns, parasites or otherwise. It’s our job to help with parasites or anything else your pet may deal with.