Toxoplasmosis in Dogs

Reviewed by Catherine Barnette, DVM on 04/30/2024. Published on 04/04/2023

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Toxoplasmosis is an infection most often associated with disease in cats. However, dogs can also be infected by Toxoplasma gondii, the parasite that causes toxoplasmosis. Fortunately, most otherwise healthy adult dogs will not show symptoms of toxoplasmosis and don’t require treatment, but there may be some instances where some dogs may need to be treated.

To help ease any worries, this article provides everything pet parents need to know about toxoplasmosis in dogs.

What Is Toxoplasmosis?

Toxoplasmosis is an infectious disease caused by a single-celled organism called Toxoplasma gondii, or T. gondii for short. T. gondii is a parasite that can infect nearly all mammals including humans, though it can only grow to maturity and reproduce in domestic and wild cats.

Toxoplasma gondii has been found all over planet Earth. If a cat eats prey animals or raw meat infected with T. gondii, the parasite will mature and reproduce in the cat’s digestive tract. When the cats infected with T. gondii defecate, their feces contain millions of infectious parasitic eggs.

Over time, a cat’s immune system forces the parasite to stop reproducing and instead, form dormant cysts in muscle and brain tissue. Humans become infected when they accidentally ingest parasite eggs from contaminated food or water, or from not washing their hands after cleaning the litter box used by a cat that is actively infected with Toxoplasma.

Toxoplasma behaves differently in dogs because they are considered intermediate hosts (i.e. the parasite cannot mature or reproduce in dogs), and infected dogs are not considered contagious to other animals or humans. Most healthy dogs can eliminate the infection on their own if they come into contact with the parasite, though puppies, geriatric dogs, young dogs with the distemper virus, and adult dogs with compromised immune systems are at higher risk for becoming sick from toxoplasmosis.

Causes of Toxoplasmosis in Dogs

Toxoplasmosis in dogs can either be an acute or chronic condition. Dogs become infected with Toxoplasma gondii by accidentally ingesting parasitic eggs in soil, eating cat poop, or eating contaminated produce or raw meat.

Symptoms of Toxoplasmosis in Dogs

Most dogs do not show any symptoms of toxoplasmosis, and even if they do, the symptoms can be quite vague. Toxoplasmosis symptoms in dogs may include:

Fever
Weight loss
Loss of appetite
Tonsillitis (may appear as drooling or difficulty swallowing)
Jaundice
Difficulty breathing
Diarrhea
Vomiting
Seizures/tremors
Incoordination
Weakness
Paralysis

If your dog is experiencing any of the symptoms listed here, please make an appointment with a veterinarian as soon as possible. These symptoms are also associated with many other disease conditions and often require veterinary assistance to diagnose and resolve the issue.

Toxoplasmosis symptoms in dogs that require treatment are more common with the acute form of the disease; the chronic form usually has no symptoms and does not require treatment.

Diagnosing Toxoplasmosis in Dogs

To diagnose toxoplasmosis, a veterinarian will conduct a full physical examination and measure vitals, including body temperature, heart rate, breathing rate, and weight. Be sure to let your veterinarian know if your dog has eaten cat poop or if you have stray cats that visit your yard. Laboratory tests on blood and urine will be ordered to evaluate your dog’s immune system and organ function.

Your veterinarian will likely order a fecal test to check for other parasites that can cause the same symptoms as toxoplasmosis. They might also order imaging tests such as radiographs (X-rays) and abdominal ultrasound to get more information. If your dog has neurological signs, your veterinarian may want to evaluate their spinal fluid for signs of infection or inflammation, and also conduct a neurological examination. Remember, symptoms of toxoplasmosis are rare in dogs, so your veterinarian may need to run a few tests to figure out what is going on.

The most specific tests for toxoplasma are serological tests that measure the level of toxoplasma proteins (antigens) present in the body. PCR is the typical test to diagnose toxoplasmosis and determine if the infection is acute or chronic.

If you are curious as to whether your dog has been exposed to toxoplasmosis, you can have their antibodies tested. If they have already been infected, they will have antibodies in their blood, however, antibody tests are not useful to determine if a dog has an active infection or if they need treatment.

Treating Dogs for Toxoplasmosis

If your dog is very sick from toxoplasmosis, they will need to be hospitalized for treatment. While hospitalized, dogs will typically receive intravenous fluid treatment for hydration and intravenous antibiotics to eliminate the infection through an IV catheter placed in their arm. If your dog has seizures, anticonvulsant medication may be prescribed to control them.

Most of the time, however, dogs will be treated for toxoplasmosis with antibiotics on an outpatient basis, as dogs rarely show symptoms or get very ill from this disease. Also remember – most dogs don’t require any treatment for toxoplasmosis. Usually it is only the dogs with compromised immune systems and very young dogs with developing immune systems that show clinical signs associated with toxoplasmosis.

Cost to Treat Toxoplasmosis in Dogs

The cost for treating toxoplasmosis in dogs depends on a few factors, starting with the testing portion of the process. The cost of testing for toxoplasmosis varies and can range from $300-$1,500. From there, the cost will vary based on the necessary treatment. Hospitalized treatment can cost upwards of $1,000, but when it comes to a simple dose of antibiotics, most dogs can be treated for under $100

How to Prevent Toxoplasmosis in Dogs

Even though Toxoplasma gondii is a common parasite, the good news is that most dogs do not get sick from it, and there are ways to minimize your dog’s exposure.

Because the parasite that causes toxoplasmosis is commonly spread by ingestion of raw meat and unwashed produce, the best way to prevent your dog from acquiring this parasite is to refrain from feeding your dog raw meat and always wash produce before giving it to them.

To avoid ingestion of cat poop, you should limit your dog’s access to it. Keep feral cats out of your yard, and if you have a cat, keep the litter box in an area where your dog cannot access it.

Additional strategies to reduce your dog’s exposure to toxoplasmosis include: