PCR detection of acute Ehrlichia canis infection in dogs

• Published in: Journal of veterinary diagnostic investigation Vol. 8; no. 4; p. 441
• Main Authors: McBride, J.W. (University of California, Davis, CA.), Corstvet, R.E, Gaunt, S.D, Chinsangaram, J, Akita, G.Y, Osburn, B.I
• Format: Journal Article
• Language: English
• Published: United States 01.10.1996
• Subjects: ACCURACY; ACUTE COURSE; ANALYTICAL METHODS; Animals; Base Sequence; CHIEN; DIAGNOSIS; DIAGNOSTIC; DIAGNOSTICO; DNA Primers; Dog Diseases; DOGS; Ehrlichia - genetics; Ehrlichia - isolation & purification; EHRLICHIA CANIS; Ehrlichiosis - diagnosis; Ehrlichiosis - veterinary; EXPERIMENTACION IN VIVO; EXPERIMENTAL INFECTION; EXPERIMENTATION IN VIVO; FASE AGUDA; Genes, Bacterial; IN VIVO EXPERIMENTATION; INFECCION; INFECCION EXPERIMENTAL; INFECTION; INFECTION EXPERIMENTALE; Luminescent Measurements; Male; Molecular Sequence Data; PCR; PERRO; POLYMERASE CHAIN REACTION; Polymerase Chain Reaction - methods; PROCESSUS AIGU; RAPID METHODS; RNA, Ribosomal, 16S - genetics; Sensitivity and Specificity; TECHNIQUE ANALYTIQUE; TECNICAS ANALITICAS
• ISSN: 1040-6387; 1943-4936
• DOI: 10.1177/104063879600800406

A polymerase chain reaction (PCR)-based detection assay that specifically detected Ehrlichia canis in dogs with acute infections was developed. A region of the 16S ribosomal RNA gene of E. canis was targeted for PCR amplification and chemiluminescent hybridization (CH) with a complementary internal 287-base pair (bp) oligonucleotide probe. The CH improved the PCR assay sensitivity 1,000-fold as compared with visualization on ethidium bromide-stained agarose gels. The PCR assay with CH (PCR/CH) detected as little as 30 fg of E. canis genomic DNA, the equivalent of approximately 150 E. canis organisms. The 495-bp product defined by the specific primers was not detected when genomic DNA from E. platys, E. chaffeensis, E. risticii, and E. equi were used in the PCR/CH assay. The PCR/CH assay was tested with unfractionated blood samples collected from 9 dogs experimentally infected with E. canis. The PCR/CH assay had greater detection sensitivity than did cell culture isolation (CCI) from infected blood. PCR/CH detected E. canis 7 days prior to CCI in 4 of 6 experimentally infected dogs. The results obtained with the PCR/CH assay otherwise consistently matched the results obtained by CCI. This PCR/CH assay is a rapid, sensitive, and specific method for E. canis detection with sensitivity comparable to or exceeding that of CCI. A diagnosis of E. canis using this PCR/CH assay can be made in 2 days as compared with 1-4 weeks for CCI. The PCR/CH assay appears to be an acceptable alternative or complement to current diagnostic techniques.