Incidence and Sero-survey of Canine Adenovirus Type 2 in Various Animal Species

Canine adenovirus type 2 (CAV-2) is the cause of a major respiratory illness in dogs. In this study, we analyzed adenovirus infections in dogs using 2000–2017 data from the Animal and Plant Quarantine Agency (APQA) and conducted a serological survey of CAV-2 infection in six animal species in Korea. In total, 38 of the 3,179 dog samples were confirmed as canine adenovirus infections. In serological survey, 1,028 dog sera, 160 raccoon dog sera, 100 cattle sera, 257 sow sera, 206 horse sera, and 106 cat sera, collected from January 2016 to July 2018, were screened for the presence of anti-CAV-2 antibodies by virus neutralization test. The seropositivity rates for dogs, raccoon dogs, cattle, sows, horses, and cats were 88.5% (910/1,028), 51.3% (82/160), 85.0% (85/100), 48.6% (125/257), 35.0% (72/206), and 2.8% (3/106), respectively. Among dogs and raccoon dogs, 1.9% (20/1,028) and 8.8% (14/160), respectively, had a virus-neutralizing antibody (VNA) titer of over 1:256. A high CAV-2 VNA titer indicates a repeated vaccination or natural infection in Korean dogs and circulation of CAV-2 in raccoon dog populations.

Indirect ELISA for the Detection of Rabies Virus Antibodies in Dog Sera

Rabies is known as the most fatal disease in all warm-blooded animals, including dogs. Among animals that transmit rabies, dogs are mainly responsible for transmitting animal rabies in Asian countries. Detection of rabies virus (RABV) antibodies in dogs is performed by fluorescent antibody virus neutralization (FAVN) test or rapid fluorescent focus inhibition test. These standard assays are difficult to carry out in diagnostic laboratories without sufficient instruments, designated RABV, and cell culture systems. An alternative assay that is easy to conduct and time efficient is required for rapid sero-surveillance following vaccination. Recombinant baculovirus expressing RABV nucleoprotein (RVN) was constructed and the recombinant protein was purified using Ni-NTA and fast protein liquid column chromatography. We developed and evaluated an indirect enzyme-linked immunosorbent assay (I-ELISA) with recombinant RVN for the detection of RABV antibodies in 122 dog serum samples. The I-ELISA results obtained from these samples were compared with FAVN results. The sensitivity, specificity, and accuracy of I-ELISA were 88.1%, 92.5%, and 91.0%, respectively, compared with FAVN. Results of I-ELISA were significantly correlated with that of FAVN (r = 0.81). These results suggest that I-ELISA with recombinant RVN is useful for sero-surveillance of RABV in dog sera.

Indirect ELISA for the Detection of Rabies Virus Antibodies in Dog Sera

Rabies is known as the most fatal disease in all warm-blooded animals, including dogs. Among animals that transmit rabies, dogs are mainly responsible for transmitting animal rabies in Asian countries. Detection of rabies virus (RABV) antibodies in dogs is performed by fluorescent antibody virus neutralization (FAVN) test or rapid fluorescent focus inhibition test. These standard assays are difficult to carry out in diagnostic laboratories without sufficient instruments, designated RABV, and cell culture systems. An alternative assay that is easy to conduct and time efficient is required for rapid sero-surveillance following vaccination. Recombinant baculovirus expressing RABV nucleoprotein (RVN) was constructed and the recombinant protein was purified using Ni-NTA and fast protein liquid column chromatography. We developed and evaluated an indirect enzyme-linked immunosorbent assay (I-ELISA) with recombinant RVN for the detection of RABV antibodies in 122 dog serum samples. The I-ELISA results obtained from these samples were compared with FAVN results. The sensitivity, specificity, and accuracy of I-ELISA were 88.1%, 92.5%, and 91.0%, respectively, compared with FAVN. Results of I-ELISA were significantly correlated with that of FAVN (r = 0.81). These results suggest that I-ELISA with recombinant RVN is useful for sero-surveillance of RABV in dog sera.