Diagnosis of duck circovirus infections by conventional and real-time polymerase chain reaction tests.
Development of the first conventional and real-time polymerase chain reaction (PCR) tests for the diagnoses of duck circovirus (DuCV) infections is described. Both tests amplified a 230 bp fragment specific to the DuCV Rep gene. Although both tests had the same detection limit (13 x 10(3) target DNA/ml) when the target DNA was diluted in water, the detection limit of the real-time test (13 x 10(4) target DNA/ml) was 10-fold less than the conventional test (13 x 10(5) target DNA/ml) when the amplifications were performed in the presence of cellular DNA. Using the conventional PCR test, DuCV DNA was detected in 85 (84%) of 101 bursa of Fabricius samples from dead or sick ducks, aged between 1 and 12 weeks, and in samples from 35 (94%) of 37 flocks. Application of the SYBR Green-based real-time PCR test to 54 selected bursa of Fabricius samples indicated that more samples were positive by real-time PCR than by conventional PCR, allowed the numbers of genome copies to be estimated and showed that some bursa of Fabricius samples contained over 10(13) genome copies/g tissue. Although DuCV infections were detected in birds aged from 1 to 12 weeks, higher virus DNA levels were detected in ducks aged older than 5 weeks than in ducks younger than 5 weeks. An in situ hybridization method for the detection of DuCV in histological samples was also developed. Additional work is required to determine the clinicopathological significance of DuCV infections.
Fringuelli
E
E
Dipartimento di Scienze Biopatologiche ed Igiene delle Produzioni Animali e Alimentari, Università degli Studi di Perugia, 06126, Perugia, Italy.
Scott
A N J
AN
Beckett
A
A
McKillen
J
J
Smyth
J A
JA
Palya
V
V
Glavits
R
R
Ivanics
E
E
Mankertz
A
A
Franciosini
M P
MP
Todd
D
D
D000818:Animals; D002060:Bursa of Fabricius / Q000821:virology; D018173:Circoviridae Infections / Q000662:veterinary* / Q000821:virology; D004372:Ducks / Q000821:virology*; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary*; D011201:Poultry Diseases / Q000175:diagnosis* / Q000821:virology*; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity