Direct Fluorescent Antibody Test (DFAT) as A Rapid-Point of Care Test for the Intra-vitam Diagnosis of Canine Distemper

Background: Canine distemper (CD) is an important fatal viral disease of dogs worldwide. Subclinical infections are common in CD and they delay the diagnosis as well as the commencement of symptomatic treatment. Methods: With the aim of early diagnosis, dogs which were brought to Infectious Disease Unit, Madras Veterinary College from April 2021 to November 2022 with the symptoms of CD used for the present study. Conjunctival (30), nasal (30) and genital (30) swabs were collected from 30 dogs that displayed signs of Canine Distemper, producing a total of 90 samples. All samples were subjected to both Nested Reverse Transcription Polymerase Chain Reaction (nRT-PCR) and Direct Fluorescent Antibody Test (DFAT) simultaneously. Result: Both tests showed concurrence in diagnosing CD with 81.11% (73 out of 90 samples). The Kappa value of 0.57 revealed that there was a moderate agreement between the results of nRT-PCR and DFAT. Moreover, nRT-PCR is expensive and time consuming compared to DFAT and the latter is economical and requires only 2 hours for results. Hence, DFAT could be considered as a rapid-point of care test for initial screening purpose as well as to avoid unnecessary euthanasia of dogs with non-infectious respiratory and nervous signs.