Symptoms of Canine Nocardiosis: Identifying Key Indicat

Popularity Characteristics

This disease is sporadically reported in certain regions, predominantly affecting working dogs such as police and hunting dogs during outdoor training, particularly in areas abundant with thorny plants. The infection occurs when the bacteria enter the dog's skin through wounds, and it is less common in domesticated dogs. Dogs of all ages, breeds, and genders can be affected, but the disease cannot be transmitted directly from pet to pet or from pets to humans.

Clinical Symptoms

The disease can manifest in three primary forms: dermatological, thoracic, and systemic.

（1）Dermatological Form

Typically chronic, the lesions are often found in the subcutaneous tissue of the limbs and neck. The wound sites may develop cellulitis, abscesses, suppurative granulomas, nodular ulcers, and multiple fistulas, which can also involve local lymph nodes.

（2）Thoracic Form

Characterized by difficulty breathing, elevated body temperature, and pronounced pain upon chest compression.

（3）Systemic Form

Presented by a rise in body temperature, loss of appetite, weight loss, coughing, difficulty breathing, and convulsions in the head, neck, and limbs.

Pathological Changes

Included are enlarged superficial lymph nodes, liver and spleen enlargement, peritonitis, ascites, nodular lung lesions, enlarged mediastinal lymph nodes, and pleural effusion.

Differential Diagnosis

（1）Canine Nocardiosis vs. Canine Distemper

Both diseases present with fever, loss of appetite, coughing, and neurological symptoms such as seizures when present. The distinction lies in the mode of transmission; Canine Distemper is transmitted via the gastrointestinal and respiratory tracts rather than through the skin, and it is characterized by a biphasic fever pattern. Microscopic examination of the sample shows pale blue nuclei, magenta cytoplasm, and red inclusions. In Canine Nocardiosis, the sample shows beadlike bacteria, Grampositive, with some exhibiting branching and filaments, and some appearing red in acidfast staining.

（2）Canine Nocardiosis vs. Canine Actinomycosis

Both diseases occur in the subcutaneous and mucous membranes, causing localized tissue abscesses, suppurative granulomas, cellulitis, and necrotic foci, leading to fistulas and discharge of pus. The difference is that Nocardia is Grampositive, nonmotile, with filaments (beadlike filaments, some with branching and filaments), acidfast aerobic reproduction, and sensitivity to sulfonamide drugs. Actinomycetes are pleomorphic bacilli or branching filaments, nonacidfast, and anaerobic in reproduction.

（3）Canine Nocardiosis vs. Canine Mycobacteriosis

Both diseases are transmitted through wounds and affect the skin, causing subcutaneous nodular granulomas, abscesses, and sometimes fistulas with pus discharge. The difference is that after treating the pus or exudate from the lesion with potassium hydroxide, the algae filaments in the sample will quickly stain, and microscopic examination will reveal multicellular, nonsegmented, rough, wide filaments, confirming the diagnosis.

Reminders

A preliminary diagnosis can be made based on the流行 characteristics and clinical symptoms, but confirmation requires laboratory tests such as smear staining or culture of secretions or tissue samples.

Preventive Measures

（1）Prevention

When dogs are working outdoors, any wounds should be immediately disinfected. Prompt treatment is crucial for sick dogs, and a poor prognosis is expected if it is concurrent with Canine Distemper.

（2）Treatment

The treatment approach involves surgical excision, thoracic drainage, and longterm use of antibiotics and sulfonamide drugs.

① Trimethoprimsulfamethoxazole (TMPSMX), 30 mg/kg body weight for dogs, taken orally twice daily for six months.

② Penicillin, 100,000 to 200,000 units/kg body weight, administered intramuscularly once daily for six months.

③ Ampicillin, 20 to 30 mg/kg body weight, taken orally twice to three times daily for six months.