A second-generation, point-of-care immunoassay provided improved detection of Anaplasma and Ehrlichia antibodies in PCR-positive dogs naturally infected with Anaplasma or Ehrlichia species

A validated second-generation SNAP 4Dx Plus (Idexx) incorporates new peptides for improved detection of antibodies against Anaplasma and Ehrlichia tick-borne pathogens in dogs. We compared the first- and second-generation SNAP 4Dx Plus using dogs naturally infected with Anaplasma or Ehrlichia species, or dogs seroreactive by an E. canis indirect fluorescent antibody test (IFAT). The second-generation immunoassay was more sensitive than the first-generation for dogs infected with A. phagocytophilum (51.1% and 29.2%, respectively), A. platys (63.6% and 35.3%, respectively), E. canis (96.2% and 88.3%, respectively), or E. ewingii (73.7% and 70.8%, respectively), and for dogs seroreactive by E. canis IFAT (87.3% and 83.9%, respectively). The second-generation immunoassay detected significantly more Anaplasma- or Ehrlichia-infected dogs that were Anaplasma (p