ABSTRACT
Objective To investigate the shedding of CAV2-ΔE3-CGS after immunization and the background of canine adenovirus (CAV) infection, and to establish a dual fluorescent quantitative PCR detection method for rabies virus (RV) and canine adenovirus type 2 (CAV2). Methods A dual fluorescent quantitative PCR detection method was established by designing specific primers and probes for E1 gene of CAV and G gene of RV for the detection of CAV2-ΔE3-CGS. Oral swabs, anal swabs and environmental samples of stray dogs from experimental animal farm and dog detention center were tested. Results The standard curves generated by this method were Y=-3.351 × logX + 44.895, R2 = .999 and Y=-3.413 × logX + 45.192, R2=0.996, respectively. The linear relationships were good, and the minimum detection limits were both 102 copies/μL. CAV2-ΔE3-CGS was not detected in experimental animal farm. CAV was detected in dog detention center, and the positive rates were 5.88% (5/85) in oral swabs, 8.24% (7/85) in anal swabs, and 4% (1/25) in environmental samples. Conclusion The dual fluorescent quantitative PCR method can be used for the detection of CAV2-ΔE3-CGS after immunization and the investigation of CAV infection. The present study has shown that no CAV2-ΔE3-CGS has been detected after immunization and CAV infection rate of stay dogs is low in Shanghai. CAV2-ΔE3-CGS oral immunization meets requirement and is applicable.
ABSTRACT
0.05). Dogs inoculated with the former vaccine developed a significantly higher immune titer than non-vaccinated dogs.CONCLUSION: The Cabopol-adjuvanted, inactivated CAV-2 vaccine was safe and induced a high VNA titer in dogs.
Subject(s)
Animals , Dogs , Adenoviruses, Canine , Amino Acids , Enzyme-Linked Immunosorbent Assay , Formaldehyde , Guinea Pigs , Madin Darby Canine Kidney Cells , Urea , VaccinesABSTRACT
Canine adenovirus type 2 (CAV-2) infection results in significant respiratory illness in dogs. Isolating and culturing CAV-2 allows for investigations into its pathogenesis and the development of vaccines and diagnostic assays. In this study, we successfully isolated a virus from a naturally infected dog in Gyeonggi-do, Korea. The virus was propagated in Madin-Darby canine kidney (MDCK) and Vero cells and showed a specific cytopathic morphology that appeared similar to a bunch of grapes. The virus was first confirmed as CAV-2 based on these cytopathic effects, an immunofluorescence assay, hemagglutination assay, and electron microscopy. The viral titer of the isolate designated APQA1601 reached 10(6.5) 50% tissue culture infections dose per mL in MDCK cells and exhibited no hemagglutination units with erythrocytes from guinea pig. The virus was also confirmed by polymerase chain reaction and next-generation sequencing. The APQA1601 strain had the highest similarity (~99.9%) with the Toronto A26/61 strain, which was isolated in Canada in 1976 when the nucleotide sequences of the full genome of the APQA1601 strain were compared with those of other CAV strains. Isolating CAV-2 will help elucidate the biological properties of CAV-2 circulating in Korean dogs.
Subject(s)
Animals , Dogs , Adenoviruses, Canine , Base Sequence , Canada , Erythrocytes , Fluorescent Antibody Technique , Genome , Guinea Pigs , Hemagglutination , Kidney , Korea , Madin Darby Canine Kidney Cells , Microscopy, Electron , Polymerase Chain Reaction , Vaccines , Vero Cells , VitisABSTRACT
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.