Comparison of the diagnostic methods on the canine adenovirus type 2 infection

Abstract

Background and aims: Canine adenovirus type 2 (CAV-2) infection is typically diagnosed histopathologically since intranuclear inclusion bodies (IN/IBs) are demonstrable in the infected lung. However, it is sometimes difficult to identify IN/IBs, particularly in autolyzed tissues or samples from both early and late stages of infection, and other methods were presently developed. Methods: Stray dog samples were evaluated by histopathology, polymerase chain reaction (PCR), and immunohistochemistry (IHC) to investigate the status of the CAV-2 infection on the stray dogs in Korea. Histologic tests were performed, and dogs with pneumonic lungs were further evaluated by IHC and PCR. Results: Pathognomonic IN/IBs were identified in 3 of 213 lungs; CAV-2 PCR was positive for 27 of 213 pneumonic lungs. A total of 7 of 27 CAV-2 PCR-positive lungs were IHC-positive. No PCR-negative lung was IHC-positive. Positive results were primarily detected in the IN/IBs of the bronchial epithelial cells, macrophages, and very rarely in the cytoplasm of bronchial epithelial cells. Conclusions: IHC was a more reliable diagnostic method than conventional pathologic methods in the present study, and suggests that IHC should be routinely used in the diagnosis of CAV-2 infection. Further, PCR alone may not be adequate for CAV-2 diagnosis.

Keywords: CAV‐2; PCR; canine adenovirus type 2; immunohistochemistry; pathology.

Figure 1

Lung tissue. Numerous prominent basophilic intranuclear inclusion bodies in the nuclei of bronchiolar epithelial cells (hematoxylin and eosin).

Figure 2

Lung tissue. Detachment and attenuation of bronchiolar epithelial cells and severe diffuse proliferative peribronchiolitis (hematoxylin and eosin).

Figure 3

Lung tissue. Numerous viral particles demonstrating a paracrystalline pattern in the bronchiolar epithelial cell nucleus (insert represents the magnified viral particles).

Figure 4

Representative patterns seen with agarose gel electrophoresis of amplified PCR products to canine adenovirus type 2 (CAV‐2). M: DNA ladder, 1 and 2: CAV‐2 positive field samples, P: CAV‐1 and CAV‐2 virus, N: DW.

Figure 5

Lung tissue. Red areas represent positive immunohistochemistry reactions using multimer molecules and were stained with alkaline phosphatase/fast red detection kit. Most positive reactions were detected in the bronchial epithelial cells.