Canine neosporosis is a worldwide disease caused by infection with the protozoa Neospora caninum, an obligate intracellular parasite.
N. caninum affects a wide range of warm-blooded animals. The domestic and wild canids are the definitive host of the parasite. They shed oocysts after ingestion of tissue cysts from infected intermediate hosts (ovine, equine, bovine, and many other species), containing bradyzoites, or oocyst-contaminated water and food. The presence of dogs in farms is considered a risk factor for production animals, as transmission cycles between dogs and cattle are common in North America.
In general, neosporosis is asymptomatic in adult and older dogs. More severe and frequent infections occur in young dogs (age less than 6 months old).
Neuromuscular signs are common in clinically affected patients, especially puppies, and may include progressive paralysis, ataxia, muscle atrophy, proprioceptive deficits, muscle swelling, muscle rigidity, arthrogryposis/joint curvature, cervical weakness, behavior changes, head tilt, blindness, anisocoria, circling, tremors, seizures, obtundation, and muscle pain. Dyspnea, coughing, cutaneous lesions, diarrhea, vomiting, fever, abdominal pain, icterus, cardiac arrhythmias, tachycardia, regurgitation, dysphagia, ascites, signs of hepatitis and/or pancreatitis, and weight loss may also be noted. Death is possible. A recent neospora caninum patient at Walking Paws had muscle contractures so severe the knee joints were bending in the opposite direction. If your pet has joints bending in the wrong direction due to muscle contractures neospora caninum should be tested for.
A wide range of diagnostic methods are currently available, but the most used is serology, ie, indirect fluorescent antibody test titers for parasite specific antibodies in blood serum samples.
There is no approved or curative treatment for canine neosporosis, but treatment with a combination of antibiotics is recommended for a minimum of 4 weeks along with physical therapy to manage clinical signs. No vaccine is available, but control strategies should be focused on the vertical and horizontal transmission of the parasite, ie, avoid feeding dogs raw or undercooked meat, and taking care with water for human and animal consumption. No medication to control transplacental transmission are available yet.
Physical therapy for Neospora caninum involves maintaining joint mobility, avoiding muscle contractures, relaxing muscles, and decreasing/delaying neurogenic muscle atrophy through the use of massage, ultrasound, passive range of motion, and balance exercises. We use ultrasound, heat, shockwave therapy, laser therapy, massage, and stretching to try to loosen these tissues. We also address any secondary pain or swelling that may be associated with the contracture. If proprioceptive/neurologic deficits are present our rehab plan may initially focus on bringing back sensation and proprioception through the use of manual stimulation. Once proprioception is improved we work on stability. We start with positional balance exercises and then progress into dynamic movements. We focus on retraining transitions, taking appropriate steps, and overall coordination. The underwater treadmill can be helpful for retraining gait through assisted walking or gait patterning. Muscle recovery can be achieved during hydrotherapy and, when necessary, through the use of electrical muscle stimulation. Severe cases may benefit from a wheelchair.
