High-throughput real-time RT-PCR assay to detect the exotic Newcastle Disease Virus during the California 2002-2003 outbreak

Beate Crossley, Sharon K. Hietala, Liu Mei Shih, Lou Lee, Evan W. Skowronski, Alex Ardans

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


During the 2002-2003 Exotic Newcastle Disease (END) outbreak in Southern California, a high-throughput real-time reverse transcriptase-polymerase chain reaction (RRT-PCR) system was developed to respond to the large diagnostic and surveillance sample workload. A 96-well RNA extraction method, using magnetic bead technology, combined with a 96-well RRT-PCR assay, allowed 1 technician to process and test more than 400 samples per day. A 3-technician team could complete testing on approximately 1,900 samples per day. The diagnostic sensitivity of the high-throughput RRT-PCR assay was 0.9967 (95% CI 0.9937-0.9997) based on 926 virus isolation confirmed positive samples. Diagnostic specificity using an initial 434 virus isolation confirmed negative samples was 100%. A diagnostic specificity of 0.9999 (95% CI 0.9999, >0.9999) was subsequently calculated on the basis of 2 false-positive results among 65,343 surveillance samples collected after the final END-positive case was confirmed in May 2003. Assay performance over 500 replicates, including reproducibility of the combined extraction and RRT-PCR amplification steps yielded a standard deviation of 0.70 RRT-PCR cycle thresholds (Ct) and a standard deviation of 0.59 Ct for the RRT-PCR steps alone. The high-throughput RRT-PCR developed for END contributed significantly to the 2002-2003 END control effort, reducing the predicted timeline for eradication from 3 years to just 11 months, primarily because of the large number of samples that could be rapidly tested. The 96-well approach described for high-throughput END RRT-PCR could be adapted to other rapid, high-volume testing needs, as required for potential foreign animal disease responses or intensive surveillance efforts.

Original languageEnglish (US)
Pages (from-to)124-132
Number of pages9
JournalJournal of Veterinary Diagnostic Investigation
Issue number2
StatePublished - Mar 2005


  • California
  • END
  • Exotic newcastle disease
  • High-throughput real-time pcr

ASJC Scopus subject areas

  • Microbiology
  • veterinary(all)


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