Development and application of multiplex PCR assays for detection of virus-induced respiratory disease complex in dogs

PIEWBANG, Chutchai; RUNGSIPIPAT, Anudep; POOVORAWAN, Yong; TECHANGAMSUWAN, Somporn

Canine infectious respiratory disease complex (CIRDC), also known as kennel cough or infectious tracheobronchitis, is a highly acute respiratory disease in dogs that affects the larynx, trachea, bronchi and, occasionally, the nasal mucosa [3, 21] . The CIRDC is not only associated with infectious pathogens, but environmental factors and host immune responses also play an equally important role [7] . The pathogens causing CIRDC consist of viruses, bacteria or both, and are airborne-transmitted from infected dogs, particularly those living in poorly ventilated kennels, animal shelters and veterinary hospitals [3] . A CIRDC infection usually results in delaying of rehoming, interruption of training courses and requires high cost treatments [7] . Mildly productive cough and nasal discharge initially present as the most common clinical signs, which is self-limited within a short period in most infected dogs. It is not fatal unless other complicating factors are involved, such as secondary bacterial infection or an immunosuppressed condition [7] . Several episodes of CIRDC infection have been shown for a variety of viral agents. Canine parainfluenza virus (CPIV) is the most frequently detected agent in CIRDC dogs [16] . Canine adenovirus type 2 (CAdV-2) and canine distemper virus (CDV) have also frequently been reported in dogs with severe respiratory distress [7, 16, 17] . Canine herpesvirus 1 (CaHV-1) has been isolated from both puppies and adult dogs with fatal dyspnea [3, 7] . Canine influenza virus (CIV) [14, 16] and canine respiratory coronavirus (CRCoV) have recently been discovered from the respiratory tract of dogs with flu-like symptoms during a massive human flu outbreak [5, 6, 8] .