Understanding Canine Distemper: Essential Facts & Preve

The incubation period of canine distemper can vary significantly depending on the source of infection, ranging from 3 to 6 days on average. The clinical symptoms of canine distemper are diverse and can be influenced by factors such as the virulence of the virus, environmental conditions, the age, breed, and immune status of the host. Approximately 50% to 70% of canine distemper infections present with subclinical symptoms, including lethargy, anorexia, fever, and upper respiratory infections. These symptoms often involve watery discharge from the eyes and nose, which may turn into mucopurulent within 1 to 2 days. Severe cases of canine distemper are more common in unvaccinated puppies aged between 84 and 112 days, which may be related to the waning of maternal antibodies. Early symptoms of natural infection, such as conjunctivitis and dry cough, may go unnoticed, and the disease can progress to productive cough, difficulty breathing, vomiting, diarrhea, tenesmus, intussusception, and ultimately death due to severe dehydration and weakness.

Neurological symptoms of canine distemper typically appear 7 to 21 days after the resolution of systemic symptoms, although some may present with neurological symptoms from the onset of fever. The likelihood of neurological symptoms can often be predicted based on certain characteristics of the systemic symptoms. While pyoderma in puppies is usually not associated with neurological symptoms, keratinization of the nose and paw pads can lead to various types of neurological disorders. Neurological symptoms are the most critical factors affecting prognosis and recovery from canine distemper. Due to the varying locations of canine distemper virus in the central nervous system, clinical symptoms can differ. Brain damage may cause mild twitching of the lips and eyelids, severe drooling, or circular movements and seizures. Damage to the midbrain, cerebellum, vestibular system, and medulla can result in abnormal gait and posture. Spinal cord damage can lead to ataxia and abnormal reflexes, while meningeal damage can cause hyperesthesia and stiffness of the neck. Recurrent, paroxysmal spasms of the masticatory muscles are common symptoms of canine distemper.

Puppies infected in utero can develop neurological symptoms between 28 and 42 days. The infected mother may show mild or no symptoms. Infection during pregnancy can lead to abortion, stillbirth, and reduced survival rates of offspring.

Newborn puppies infected with canine distemper before the permanent teeth emerge can suffer severe damage to the enamel, resulting in irregular tooth growth. Experimental infection in puppies younger than 7 days can also present with myocarditis, characterized by symptoms such as respiratory distress, depression, anorexia, weakness, and exhaustion. Pathological changes include myocardial degeneration, necrosis, and mineralization, accompanied by inflammatory cell infiltration.

Eye damage in canine distemper is caused by the virus attacking the optic nerve and retina. Optic neuritis is characterized by sudden blindness, dilated pupils, and absent pupillary reflexes. Inflammatory exudates can lead to retinal detachment. Chronic, inactive basal damage is associated with retinal atrophy and scar formation.

Blood tests may show a decrease in lymphocytes and a reduction in phagocytic function of leukocytes. Occasionally, viral antigens and inclusions can be detected in lymphocytes and monocytes.

The course and prognosis of canine distemper are influenced by factors such as the animal's breed, age, immune status, the quantity and virulence of the virus, and the type of secondary infection. Dogs without complications usually have a low mortality rate. Dogs with concurrent pneumonia and encephalitis have a mortality rate of up to 70% to 80%. In areas where canine distemper has not occurred before, the susceptibility of animals is extremely high, and mortality can reach over 90%.

[Treatment Plan]

The treatment approach focuses on antiviral therapy, preventing secondary infections, and symptomatic management.

Antiviral:

Prescription 1: Canine distemper virus monoclonal antibody, 0.5 to 1 milliliter per kilogram, administered subcutaneously or intramuscularly, once daily for 3 days; for severe cases, double the dose.

Prescription 2: Virazole, 5 to 7 milligrams per kilogram, administered subcutaneously or intramuscularly, once daily.

Prescription 3: Shuanghuanglian, 60 milligrams per kilogram, administered subcutaneously or intramuscularly, once daily.

Prescription 4: Interferon, 100,000 to 200,000 units per dose, administered subcutaneously or intramuscularly, every other day.

Preventing Secondary Infections, Antibiotics:

Prescription 5: Ampicillin, 20 to 30 milligrams per kilogram, administered orally, twice to three times daily; or 10 to 20 milligrams per kilogram, administered intravenously, subcutaneously, or intramuscularly, twice to three times daily.

Prescription 6: Cefazolin sodium, 15 to 30 milligrams per kilogram, administered intravenously or intramuscularly, three to four times daily.

Prescription 7: Suprax (amoxicillin and clavulanate potassium suspension), 0.1 milliliter per kilogram, administered intramuscularly or subcutaneously, once daily.

Prescription 8: Enrofloxacin, 2.5 to 5 milligrams per kilogram, administered orally, subcutaneously, or intravenously, twice daily.

Fluid Replacement, Boosting Immune Response:

Prescription 9: ATP, coenzyme A, vitamin C, and glucose saline to replenish body fluids.

Cooling and Detoxifying:

Prescription 10: Bupleurum injection, 2 milliliters per dose, administered intramuscularly, twice daily.

Prescription 11: Qingkailing oral liquid, 0.2 to 0.4 milliliters per kilogram, administered orally or intravenously, twice daily.

Antiemetic:

Prescription 12: Metoclopramide, 0.2 to 0.5 milligrams per kilogram, administered orally or subcutaneously, three to four times daily; or 0.01 to 0.08 milligrams per kilogram per hour, administered intravenously.

Prescription 13: Omeprazole, 0.5 to 1.5 milliliters per kilogram, administered intravenously, subcutaneously, or orally, once daily, for up to eight weeks.

Relieving Respiratory Symptoms:

Prescription 14: Aminophylline, 10 to 15 milligrams per kilogram, administered orally, twice to three times daily; or 50 to 100 milligrams per dose, administered intramuscularly or intravenously.

Prescription 15: Cough syrup, 25 milligrams per dose, administered orally, twice to three times daily.

Antiinflammatory Hormones:

Prescription 16: Dexamethasone, 0.5 milligrams per kilogram, administered orally or intramuscularly, once to twice daily.

Relieving Neurological Symptoms:

Prescription 17: Chlorpromazine, 3 milligrams per kilogram, administered orally, twice daily; 1 to 2 milligrams per kilogram, administered intramuscularly, once daily; or 0.5 to 1 milligram per kilogram, administered intravenously, once daily.

Prescription 18: Phenytoin sodium, 100 to 200 milligrams per dose, administered orally, once to twice daily, or 5 to 10 milligrams per kilogram, administered intravenously.

Prescription 19: Diazepam, 0.2 to 0.5 milligrams per kilogram per hour, administered intravenously in 0.9% sodium chloride; 0.3 milligrams per kilogram per hour, administered intravenously in 0.9% sodium chloride for cats.