2017 ACVIM Forum Research Abstract Program

While specific DNA can be extracted from blood dried on filter paper, the sensitivity will be decreased compared to whole blood. If this technique is used, the commercial kit is likely to be more sensitive than an overnight PBS wash. E. ewingii is the most prevalent tick-transmitted Ehrlichia spp. identified in dogs from the Southern US. Fever, lameness, neutrophilic polyarthritis and neurologic abnormalities are considered common clinical findings in dogs naturally-infected with E. ewingii; however, nonclinical dogs can be PCR+. To further assess the clinicopathologic features in E. ewingii PCR+ cases, we analyzed the medical records of 30 naturally-infected dogs. To be included in this study, dogs had clinical data, archived whole blood available from North Carolina State University-College of Veterinary Medicine, and were E. ewingii PCR (+) and PCR (-) for other vectorborne pathogens including Ehrlichia spp. (E. canis, E. chaffeensis, and Panola Mountain Ehrlichia), Anaplasma spp., Babesia spp., Bartonella spp., Hemotropic Mycoplasma spp., and Rickettsia spp. Based upon diagnostic and/or retrospective research testing, all 30 dogs satisfied the inclusion criteria. Frequently reported physical exam findings included joint pain and effusions 10/30 (33.3%); heart murmur 8/30 (26.75); organomegaly 7/30 (23.3%); vomiting 6/30 (20%) and fever 5/30 (16.7%). Of the 30 E. ewingii PCR+ dogs, 28, 26 and 20 had corresponding CBCs, biochemistry panels and urinalyses, respectively. Hematological and biochemical abnormalities included increased abnormal lymphocytes 18/28 (64.3%); neutrophilia 15/28 (53.6%), of which 9/15 (60%) were characterized by a left shift; anemia 14/28 (50%), of which 8/14 (57%) were characterized as regenerative; monocytosis 13/28 (46.4%); lymphopenia 12/28 (42.9%); thrombocytopenia 11/28 (39.3%); elevated ALP 13/26 (50%) and ALT 10/26 (38.5%), of which only two dogs were receiving corticosteroids; hypoalbuminemia 9/26 (34.6%); and elevated creatinine 6/26 (23.1%). Urinalyses abnormalities included albuminuria 11/20 (55%); proteinuria with inactive sediment 6/20 (30%); and bilirubinuria 6/20 (30%). Of the 7 dogs with urine/protein/creatinine ratios, 6 (85.7%) were greater than 1.5 (range: 1.74 -11.7). Canine vector-borne disease IFA serology results were available for 28/30 (93.3%) dogs (no sera submitted for 2 dogs), of which 13/28 (46.4%) were E. canis IFA seroreactive (titers ≤ 1:256) and 5/28 (17.8%) were R. rickettsii (spotted fever group rickettsia) IFA seroreactive (titers ≤ 1:256). All dogs were Babesia spp., and Bartonella spp. seronegative. Using the SNAP Ò 4Dx Ò Plus test kit, 23/29 (79.3%) serum or blood samples were Ehrlichia (+), 1/29 (3.4%) was Lyme (+) and all dogs were Anaplasma antibody (-) and Dirofilaria immitis antigen (-). The most frequent medical record diagnoses included renal disease 6/30 (20%); IMHA 5/30 (16.7%); neurologic disease 4/30 (13.3%); polyarthritis 3/30 (10%); hepatic disease 3/30 (10%); cancer 3/30 (10%); and other or undiagnosed 3/30 (30%) illnesses. Ehrlichiosis was the sole diagnosis for only 1/30 (0.033%) dogs and was listed concurrently with other diagnoses for 8 (26.6%) dogs. We hypothesize that infection with E. ewingii may contribute to co-morbidities or function as a precipitating factor in a spectrum of clinical syndromes in dogs. This hypothesis will be tested using inferential statistics and a large diagnostic data set from IDEXX Laboratories, Inc. The cause of proliferative