Canine Adenovirus Type II Infection: Overview and Manag

Key Features of the Disease

The disease is primarily transmitted by infected dogs and foxes, primarily through respiratory routes. It affects dogs and foxes of all ages, but is most common in young dogs and foxes, particularly those who have just been weaned. Puppies and kits are particularly susceptible, with outbreaks often affecting litters of puppies under four months old, leading to high mortality rates. Infected dogs can carry the virus for extended periods and the disease can occur yearround, making it challenging to eradicate once it appears in a population.

Symptoms

Affected dogs exhibit symptoms such as fever, persistent dry cough, rapid breathing, loss of appetite, muscle tremors, and cyanosis of the mucous membranes. Some cases may also present with vomiting and diarrhea, and many die from pneumonia.

Pathological Changes

The main pathological changes include pneumonia and bronchitis, with the lungs showing incomplete expansion, congestion, and consolidation. Occasionally, hyperplastic adenoma lesions may be observed, along with congested and hemorrhagic bronchial lymph nodes.

Differential Diagnosis

1. Canine Adenovirus Type II Infection vs. Canine Hepatitis

Both conditions present with symptoms like fever, anorexia, depression, and diarrhea.

Distinguishing Features: Canine hepatitis is characterized by a high fever that persists, a biphasic fever pattern, and some dogs may develop a temporary corneal opacity, forming a bluewhite corneal opacity known as "blue eye." Postmortem examination reveals liver enlargement, thymic edema; necrotic foci in the renal cortex; hemorrhage in the gastric serosa, subcutaneous tissue, lymph nodes, thymus, and liver.

2. Canine Adenovirus Type II Infection vs. Canine Distemper

Both conditions share symptoms like anorexia, depression, and diarrhea.

Distinguishing Features: Canine distemper is more common in puppies aged 2 to 4 months, with pronounced neurological symptoms. Postmortem examination shows congestion and hemorrhage in the gastrointestinal mucosa, and hemorrhages in the liver, heart, spleen, kidneys, and meninges with effusion.

3. Canine Adenovirus Type II Infection vs. Canine Parvovirus Infection

Both conditions present with symptoms like fever, anorexia, depression, vomiting, and diarrhea.

Distinguishing Features: Canine parvovirus infection is marked by sudden vomiting, diarrhea with a foul smell, and later stages with blood in the stool. Dogs may have persistent vomiting. Postmortem examination reveals hemorrhagic mucosa in the small intestine, enlarged mesenteric lymph nodes with congestion and hemorrhage, and nonsuppurative necrosis in the myocardium or endocardium.

4. Canine Adenovirus Type II Infection vs. Canine Salmonellosis

Both conditions present with symptoms like fever, difficulty breathing, anorexia, depression, vomiting, and diarrhea.

Distinguishing Features: Canine salmonellosis has severe vomiting and diarrhea, with extensive edema of the gastrointestinal mucosa, necrosis in some segments of the intestines, ulceration in the upper part of the duodenum, enlarged mesenteric lymph nodes with hemorrhage; spleen enlargement with hemorrhagic spots and necrotic foci on the surface; and pericarditis and myocarditis with serous or fibrinous exudates.

5. Canine Adenovirus Type II Infection vs. Canine Leptospirosis

Both conditions present with symptoms like depression, anorexia, vomiting, and fever.

Distinguishing Features: Dogs with leptospirosis have marked jaundice, blood in the stool and urine (urine appearing like soybean oil), and painful muscle reactions.

Reminders

A preliminary diagnosis can be made based on the epidemiological characteristics, clinical symptoms, and pathological changes. For a definitive diagnosis, virus isolation and serological tests (serum neutralization test and hemagglutination inhibition test) are necessary.

Preventive Measures

1. Prevention

① Enhance husbandry management, regular disinfection, and prevent the entry of the virus. Isolate and treat affected dogs promptly if the disease occurs.

② Use attenuated vaccines or combined vaccines for regular immunization, which can be highly effective. Pet dogs must also receive planned immunizations for female dogs and puppies, ensuring lifelong immunity after recovery.

③ Emergency prevention can use homologous or heterologous bivalent or trivalent immune sera or immune gamma globulin, but the protection period is limited to only 2 weeks.

2. Treatment

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

① Antiviral

Ribavirin, 57 mg/kg body weight for dogs, administered subcutaneously or intramuscularly once daily;

Interferon, 100,000200,000 units per dose for dogs, administered subcutaneously or intramuscularly every other day.

② Antibacterial

Ampicillin, 2030 mg/kg body weight for dogs, taken orally twice to three times daily, or 1020 mg/kg body weight, administered subcutaneously or intramuscularly or intravenously twice to three times daily;

Cefazolin sodium, 13 mg/kg body weight for dogs, administered intramuscularly or intravenously three to four times daily;

Supron (Amoxicillin and Clavulanate Potassium Suspension), 0.1 mL/kg body weight for dogs and cats, administered subcutaneously or intramuscularly once daily;

Trimethoprimsulfamethoxazole, 15 mg/kg body weight for dogs, taken orally or administered subcutaneously twice daily.

③ Coughsuppressing and expectorant

Potassium iodide, 0.21 gram per dose, taken orally three times daily;

Pentoxyverine, 2 mg per dose for dogs, taken orally twice to three times daily.

④ Fluid replacement

Adenosine triphosphate (ATP), coenzyme A, vitamin C, 50% glucose saline, 5% glucose, etc.