title: Detection of heartworm infection in dogs via PCR amplification and electrospray ionization mass spectrometry of nucleic acid extracts from whole blood samples.
abstract: OBJECTIVE
  To develop and evaluate a rapid and accurate assay involving PCR amplification and electrospray ionization mass spectrometry of nucleic acid extracts from whole blood samples for the detection of Dirofilaria immitis infection in dogs.
  
  
  METHODS
  Whole blood nucleic acid extracts from 29 dogs experimentally infected with D immitis (and in which circulating D immitis antigen was detected) and 10 uninfected dogs.
  
  
  METHODS
  16 of the 29 whole blood samples from infected dogs were examined at the time of collection for circulating microfilaria. Nucleic acids were extracted from all whole blood specimens and underwent PCR amplification with 12 PCR primer pairs designed to detect a wide range of pathogens (including the Wolbachia endosymbiont of D immitis) and electrospray ionization mass spectrometry.
  
  
  RESULTS
  On the basis of assay results, heartworm infection was detected in 13 of 13 antigen-positive dogs of unknown microfilaria status, 11 of 11 antigen-positive dogs with circulating microfilaria, 0 of 3 antigen-positive dogs tested at 3 months after larval infection, 0 of 2 antigen-positive dogs with occult infections, and 0 of 10 uninfected dogs.
  
  
  CONCLUSIONS
  With the assay under investigation, it was possible to identify D immitis infection in dogs with circulating microfilaria via detection of the obligate Wolbachia endosymbiont of D immitis. It was not possible to identify dogs with occult infections, which suggested that circulating microfilaria must be present to detect infection with this assay, although further studies would be required to verify that finding.
authors.affiliation: Ibis Biosciences Incorporated, 2251 Faraday Ave, Ste 150, Carlsbad, CA 92008, USA. christopher.crowder@abbott.com
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Crowder
authors.forename: Heather E
authors.initials: HE
authors.lastname: Matthews
authors.forename: Megan A
authors.initials: MA
authors.lastname: Rounds
authors.forename: Feng
authors.initials: F
authors.lastname: Li
authors.forename: Steven E
authors.initials: SE
authors.lastname: Schutzer
authors.forename: Rangarajan
authors.initials: R
authors.lastname: Sampath
authors.forename: Ranga
authors.initials: R
authors.lastname: Sampath
authors.forename: Steven A
authors.initials: SA
authors.lastname: Hofstadler
authors.forename: David J
authors.initials: DJ
authors.lastname: Ecker
authors.forename: Mark W
authors.initials: MW
authors.lastname: Eshoo
mesh_terms: D000818:Animals; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D004184:Dirofilariasis / Q000175:diagnosis* / Q000235:genetics; D004283:Dog Diseases / Q000175:diagnosis* / Q000235:genetics; D004285:Dogs; D013058:Mass Spectrometry / Q000379:methods / Q000662:veterinary; D008969:Molecular Sequence Data; D009696:Nucleic Acids / Q000097:blood*; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D017422:Sequence Analysis, DNA / Q000662:veterinary
chemical_list: D017931:DNA Primers; D004275:DNA, Ribosomal; D009696:Nucleic Acids