Canine Parvovirus Infection: Understanding and Preventi

流行特点

This disease primarily affects dogs, with a high incidence among puppies aged 2 to 4 months. Dogs younger than 2 months or older than 5 weeks are rarely affected, though purebred dogs are more susceptible than mixed or indigenous breeds. Adult dogs typically exhibit milder symptoms. Other canid species, such as wild dogs, coyotes, hyenas, raccoons, and foxes, can also be infected.

Transmission

Infected dogs and those that have recovered but still carry the virus are the main sources of transmission. The virus is shed through secretions and excretions, infecting other susceptible animals via the digestive tract and possibly through vertical transmission via the placenta. Humans, flies, and cockroaches can act as mechanical carriers of the virus.

Occurrence

The disease can occur yearround, with spring and autumn being peak seasons. Weather changes, poor husbandry conditions, and secondary or mixed infections can exacerbate the condition.

Clinical Symptoms

The disease manifests primarily as enteritis and myocarditis, with some cases presenting a mixed form.

Enteritis Type

Incubation Period: 714 days

Symptoms: Sudden onset with vomiting, depression, loss of appetite, fever (4041°C), diarrhea, gray or yellowish feces with a large amount of mucus and pseudomembranes, often resembling soy sauce or blood, and a foul odor. Dogs quickly become dehydrated.

White Blood Cell Count: Decreased in the absence of secondary infections.

Recovery: Most dogs recover within 710 days, but young puppies often succumb to the disease. Mortality rates generally decrease with age.

Myocarditis Type

Affected Age: Mainly 36weekold puppies

Symptoms: Isolation, listlessness, pale mucous membranes, rapid and weak pulse, difficulty breathing, heart murmurs on auscultation, and reduced R waves and elevated ST waves on an ECG before death. Dogs die due to heart failure.

Pathological Changes

Enteritis Type

Morphological Changes: Thickened intestinal mucosa, narrowed lumen,皱褶, or ulcerative lesions; red porridgelike contents or clots mixed with purpleblack, with a foul odor; severe hemorrhage in the jejunum and ileum; enlarged, congested mesenteric lymph nodes; red, edematous gastric mucosa with albuminous mucus; enlarged, red liver with yellowish foci and noncoagulable blood on sectioning; dilated gallbladder with a large amount of yellowgreen bile; enlarged spleen with purple spots (hemorrhagic infarction) or grayish white necrotic foci on the surface; grayish yellow kidneys with white spots on the surface; hemorrhage in the mucosa of the bladder neck.

Myocarditis Type

Morphological Changes: Enlarged heart, nonsuppurative necrotic foci in myocardium and endocardium; severe pulmonary edema and consolidation.

Differential Diagnosis

1. Canine Parvovirus Infection vs. Canine Coronavirus Infection

Both infections present with fever, vomiting, diarrhea, and intestinal mucosal congestion, necrosis, and desquamation, along with enlarged mesenteric lymph nodes and hemorrhage. The difference lies in the severity of diarrhea in canine coronavirus infections, which may be severe, with feces appearing white, yellow, green, or brown, sometimes喷射状, with hemorrhagic gastritis and desquamation, and enlarged spleen and gallbladder. In canine parvovirus infections (myocarditis type), nonsuppurative necrosis is visible in the myocardium or endocardium, and the myocardium is soft.

2. Canine Parvovirus Infection vs. Canine Rotavirus Infection

Both infections present with fever, vomiting, diarrhea, and intestinal mucosal congestion, necrosis, and desquamation. The difference lies in the age of the affected dogs in canine rotavirus infections, which are more common in puppies aged 2 to 4 months, with hemorrhagic gastritis and desquamation, and enlarged spleen and gallbladder.

3. Canine Parvovirus Infection vs. Canine Distemper

Both infections present with fever, vomiting, diarrhea, and intestinal mucosal congestion and hemorrhage. The difference lies in the biphasic fever pattern and marked neurological symptoms in canine distemper cases, along with congestion and effusion in the meninges.

4. Canine Parvovirus Infection vs. Canine Campylobacteriosis

Both infections present with fever, vomiting, diarrhea, bloodlike feces, dehydration, and intestinal mucosal congestion and hemorrhage. The difference lies in the liver congestion and ascites in canine campylobacteriosis cases, with a marked response to antibiotic treatment.

5. Canine Parvovirus Infection vs. Canine Salmonellosis

Both infections present with fever, vomiting, diarrhea, intestinal mucosal congestion, necrosis, and desquamation, and enlarged mesenteric lymph nodes and hemorrhage. The difference lies in the enlarged liver (23 times) and spleen (68 times) with numerous hemorrhagic and grayish yellow necrotic foci on the surface and in the substance, with a marked response to antibiotic treatment.

Tips

Based on the epidemiological characteristics, clinical symptoms, and characteristic pathological changes, a preliminary diagnosis can be made. Cases that suddenly become ill, vomit, and lose their appetite, with a high degree of depression, should be considered for parvovirus infection. Rapid detection kits for canine parvovirus antibodies can also be used.

Prevention and Control Measures

Prevention

1. Vaccination: Parvovirus infection can induce a strong immunity in dogs. Vaccination should be administered repeatedly to improve the immune response in dogs that already have antibodies.

2. Highly Immune Serum and Antibiotics: A combination of highly immune serum and antibiotics can provide some prevention and treatment.

Treatment

The treatment principle is antiviral, prevention and treatment of secondary infections, symptomatic treatment, and supportive therapy.

1. Antiviral Therapy:

Canine parvovirus monoclonal antibody: 0.51 mL/kg body weight, administered subcutaneously or intramuscularly once daily for 3 days; for severe cases, double the dose.

Ribavirin: 57 mg/kg body weight, administered subcutaneously or intramuscularly once daily.

Interferon: 1020 million units per dose, administered subcutaneously or intramuscularly every other day.

2. Antibacterial and Antiseptic Therapy:

Ampicillin: 2030 mg/kg body weight, administered orally twice or three times daily, or 1020 mg/kg body weight, administered intramuscularly or intravenously twice or three times daily.

Cefazolin sodium: 1530 mg/kg body weight, administered intramuscularly or intravenously three or four times daily.

Suprax (amoxicillin clavulanate potassium suspension): 0.1 mL/kg body weight, administered intramuscularly once daily.

Enrofloxacin: 2.55 mg/kg body weight, administered orally or intravenously twice daily.

3. Antiemetic Therapy:

Metoclopramide: 0.20.5 mg/kg body weight, administered orally or subcutaneously three or four times daily.

Aemmor: 2 mL per dose, administered subcutaneously or intramuscularly twice daily.

Omeprazole: 0.51 mg/kg body weight, administered orally, subcutaneously, or intravenously once daily, for up to 8 weeks.

4. Hemostasis:

Ethamsylate: 24 mL per dose, administered intramuscularly or intravenously.

Vitamin K: 1030 mg per dose, administered intramuscularly.

5. Treatment of Diarrhea:

Montmorillonite: 250500 mg/kg body weight, administered orally.

Vidicon: 0.020.08 g/kg body weight, administered orally twice daily for 24 days.

6. Fluid Replacement:

Adenosine triphosphate (ATP), coenzyme A, vitamin C, 50% glucose saline, lactic acid Ringer's solution, 5% glucose, etc.

Notes

Parvovirus is highly resistant to the external environment. Disinfection should use bleaching powder, sodium hydroxide, formaldehyde solution, and ammonia water, etc.