Comparison of two clinic-based immunoassays with the immunofluorescence antibody test for the field diagnosis of canine monocytic ehrlichiosis.
The aim of this study was to compare a clinic-based enzyme-linked immunosorbent assay (immunocomb-Eliza, Biogal, Israel) and a field-based dot-blot enzyme-linked immunoassay (DBELIA) with the indirect immunofluoresence antibody test (IFAT) used for the field diagnostics of canine monocytic ehrlichiosis (CME). The total test samples was 60; out of them 52 serum samples came from naturally exposed police German shepherd dogs and 8 from adult mongrels infected with viable Ehrlichia canis propagated in a dog macrophage laboratory cell line (DH82). The DBELIA test was positive in 86.7% (56/60) and negative in 13.3% (8/60), while the immunocomb-Eliza was positive in 91.7% (55/60) and negative in 8.3% (5/60). IFAT revealed 90.0% (54/60) of DBELIA samples as positive while 10.0% (6/50) as negative, with an agreement of 83.3% (50/60). IFAT revealed 96.7% (58/60) of immunocomb-Eliza samples as positive and 3.3% (2/60) as negative, with an agreement of 91.7% (55/60). There was an overall agreement of 86.7% (52/60) among the three assays. Five (62.5%) of the 8 disagreement were of low IFAT, titre range < 1:240 attributable to false initial IFAT results from non-specific antibody binding, cross-reactivity or antigenic variations. A positive correlation was observed in the results of the 3 assays with correlation coefficients (r2) of 0.8214 at P < 0.0001 and 0.8984 at P < 0.001 for IFAT-DBELIA and IFAT-immunocomb-Eliza, respectively. No statistically significant differences were observed in their results. The chi-square values were 0.9021, P-0.3142 and 0.04322, P-0.7624 for DBELIA and immunocomb-Eliza, respectively. Sensitivities and specificities were 92.6%, 83% and 96.0%, 87.0% for DBELIA and immunocomb-Eliza, respectively. When based on IFAT titre range of over 1:240. Both assays were sensitive and specific for the field diagnosis of CME but the immunocomb-Eliza is more sensitive and specific than the DBELIA, but the latter saves time, requires no special equipment and personnel and has a preservable shelf-life (>1 year) for its dot-antigen package.
Okewole
E A
EA
Department of Veterinary Medicine, University of Ibadan, Ibadan, Nigeria. doctorokewole@yahoo.com
Adejinmi
J O
JO
D000818:Animals; D004283:Dog Diseases / Q000175:diagnosis* / Q000382:microbiology; D004285:Dogs; D041061:Ehrlichia canis / Q000302:isolation & purification*; D016873:Ehrlichiosis / Q000175:diagnosis / Q000662:veterinary*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D008297:Male; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity
D011933:Reagent Kits, Diagnostic