Objective—To determine whether Haemobartonella
canis and Mycoplasma haemofelis (formerly known
as H felis [large form]) can be differentiated by use of
comparative analysis of gene sequences.
Sample Population—Blood samples obtained from
3 dogs infected with H canis and 2 cats infected with
Procedure—The partial 16S rDNA and ribonuclease P
RNA (RNase P) genes were amplified, cloned, and
sequenced in blood samples obtained from H canis-infected
dogs and M haemofelis-infected cats. The
DNA sequences were subjected to comparative
Results—The 16S rDNA sequences of H canis and M
haemofelis were nearly identical (homology of 99.3 to
99.7%). In contrast, RNase P gene sequences had a
lower degree of sequence homology between the 2
organisms (94.3 to 95.5%).
Conclusions and Clinical Relevance—Haemobartonella
canis and M haemofelis are not identical
organisms. Molecular differentiation of H canis and M
haemofelis is more clearly evident by use of comparative
analysis of RNase P gene sequences than by
comparative analysis of 16S rDNA gene sequences.
(Am J Vet Res 2002;63:1385–1388)
Objective—To evaluate the sensitivity and specificity of a commercially available in-clinic ELISA for detection of heartworm infection and tick-borne diseases in dogs.
Sample Population—846 serum, plasma, or blood samples obtained from dogs.
Procedures—Samples were evaluated via the in-clinic ELISA to detect antibodies against Anaplasma phagocytophilum, Ehrlichia canis, and Borrelia burgdorferi and Dirofilaria immitis (heartworm) antigen. True infection or immunologic status of samples was assessed by use of results of necropsy, an antigen assay for D immitis, and immunofluorescence assay or western blot analysis for antibodies against B burgdorferi, E canis, and A phagocytophilum.
Results—Sensitivity and specificity of the in-clinic ELISA for detection of heartworm antigen (99.2% and 100%, respectively), antibodies against B burgdorferi (98.8% and 100%, respectively), and antibodies against E canis (96.2% and 100%, respectively) were similar to results for a similar commercial ELISA. In samples obtained from dogs in the northeast and upper Midwest of the United States, sensitivity and specificity of the in-clinic ELISA for antibodies against Anaplasma spp were 99.1% and 100%, respectively, compared with results for an immunofluorescence assay. Samples from 2 dogs experimentally infected with the NY18 strain of A phagocytophilum were tested by use of the in-clinic ELISA, and antibodies against A phagocytophilum were detected by 8 days after inoculation. Antibodies against Anaplasma platys in experimentally infected dogs cross-reacted with the A phagocytophilum analyte. Coinfections were identified in several of the canine serum samples.
Conclusions and Clinical Relevance—The commercially available in-clinic ELISA could be used by veterinarians to screen dogs for heartworm infection and for exposure to tick-borne pathogens.