Canine Adenovirus Type II Infection

1 Canine Adenovirus Type II Infection

Epidemiology

Sick dogs and foxes are the source, spread by respiratory tract. It infects dogs and foxes of all ages but is common in puppies and fox cubs, especially just-weaned ones, and can cause whole-litter illness in dogs under 4 months with high mortality. Dogs can carry the virus long-term after infection; it can occur in any season and, once in a group, is hard to eradicate.

Clinical symptoms

The dog has fever, persistent dry cough, rapid breathing, poor appetite, muscle tremors and cyanotic mucosa; some cases vomit and diarrhea and die of pneumonia.

Pathological changes

The main changes are pneumonia and bronchitis: lung atelectasis, congestion and consolidation, sometimes proliferative adenomatoid foci, and congested bleeding bronchial lymph nodes.

Differential diagnosis

1. Canine adenovirus type II infection vs. canine infectious hepatitis

Both show fever, anorexia, depression and diarrhea.

Difference: infectious hepatitis has sustained high fever with a clear biphasic pattern; some recovering dogs show a transient corneal opacity, a blue-white corneal nebula known as blue eye. At necropsy the liver is enlarged with thymic edema; the renal cortex shows gray-white necrotic foci; there is bleeding of the gastric serosa, subcutaneous tissue, lymph nodes, thymus and liver.

2. Canine adenovirus type II infection vs. canine distemper

Both show anorexia, depression and diarrhea.

Difference: distemper mostly affects 2-4 month puppies with obvious neurological signs; at necropsy the GI mucosa is congested and bleeding, and the liver, heart, spleen and kidney bleed, with congested meninges and effusion.

3. Canine adenovirus type II infection vs. canine parvovirus infection

Both show fever, anorexia, depression, vomiting and diarrhea.

Difference: parvovirus cases suddenly vomit and have diarrhea with foul stool, later bloody, and intractable vomiting; at necropsy the small-intestinal mucosa bleeds, mesenteric nodes enlarge, congest and bleed, dark red; the myocardium or endocardium shows non-suppurative necrosis.

4. Canine adenovirus type II infection vs. canine salmonellosis

Both show fever, labored breathing, anorexia, depression, vomiting and diarrhea.

Difference: salmonellosis cases have severe vomiting and diarrhea; the GI mucosa is widely edematous with some segments necrotic, duodenal ulcers, enlarged bleeding mesenteric nodes; the spleen enlarges with petechiae and gray necrotic foci; the heart shows serous or fibrinous pericarditis and myocarditis.

5. Canine adenovirus type II infection vs. canine leptospirosis

Both show depression, anorexia, vomiting and fever.

Difference: leptospirosis cases have obvious icteric mucosa, bloody stool and hematuria (bean-oil-like urine), and painful muscle reactions.

Notes

A preliminary diagnosis is based on epidemiology, clinical signs and pathology; definitive confirmation requires virus isolation and serology (serum neutralization and hemagglutination-inhibition tests).

Prevention and treatment

(1) Prevention

1. Strengthen husbandry, disinfect regularly, and prevent virus introduction. Isolate sick dogs promptly on onset and give symptomatic treatment.

2. Modified-live or combined vaccines given regularly provide good protection. Pet dogs need planned immunization of both dam and puppies; recovery gives lifelong immunity.

3. For emergency prevention, use homologous or heterologous bivalent or trivalent immune serum or immune globulin, but protection lasts only within 2 weeks.

(2) Treatment

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

1. Antiviral.

Ribavirin: 5-7 mg/kg subcutaneously or intramuscularly once daily.

Interferon: 100,000-200,000 IU per dose subcutaneously or intramuscularly every 2 days.

2. Antibacterial.

Ampicillin: 20-30 mg/kg orally 2-3 times daily, or 10-20 mg/kg subcutaneously/intramuscularly/intravenously 2-3 times daily.

Cefazolin sodium: 1-3 mg/kg intramuscularly or intravenously 3-4 times daily.

Clavamox (amoxicillin-clavulanate suspension): 0.1 mL/kg subcutaneously or intramuscularly once daily.

Co-trimoxazole: 15 mg/kg orally or subcutaneously twice daily.

3. Cough relief and expectorant.

Potassium iodide: 0.2-1 g per dose orally 3 times daily.

Pentoxyverine: 2 mg per dose orally 2-3 times daily.

4. Fluid therapy.

ATP, coenzyme A, vitamin C, 50% glucose-saline, 5% glucose, etc.