Abstract
Subcutaneous inoculation of dogs with Ehrlichia canis was investigated as a more appropriate model of canine ehrlichiosis, which is naturally transmitted by arthropod vectors. A dose-dependent response occurred following subcutaneous inoculation of seven groups of dogs with log concentrations of E. canis-infected canine-origin cells. Ehrlichial infection in dogs was defined as concurrence of an increased titer of anti-E. canis immunoglobulin G (IgG) antibody in serum, a decreased platelet concentration, and isolation of E. canis by blood culture. In dogs administered the two lowest doses, no changes were detected. In seven of nine dogs administered three intermediate doses, the only change detected was a transient and mild increase in the anti-E. canis IgG antibody titer in serum. Only two of nine dogs inoculated with the intermediate doses developed an ehrlichial infection. Five of six dogs administered the two highest dose of E. canis developed an ehrlichial infection. These dogs had the highest IgG antibody titers in serum and the earliest isolation of E. canis from blood. In dogs that developed an ehrlichial infection, thrombocytopenia occurred by 28 days after inoculation, while increased IgG antibody titers in serum and blood cultures positive for E. canis occurred as early as 14 days postinoculation. Thrombocytopenia and seroconversion occurred later in the course of infection than previously reported for ehrlichial infections induced by intravenous inoculation. The route of administration and E. canis inoculum size can influence the course of ehrlichial infection and should be regarded as important variables in experimentally induced canine ehrlichiosis.
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Selected References
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- Buhles W. C., Jr, Huxsoll D. L., Ristic M. Tropical canine pancytopenia: Clinical, hematologic, and serologic response of dogs to Ehrlichia canis infection, tetracycline therapy, and challenge inoculation. J Infect Dis. 1974 Oct;130(4):357–367. doi: 10.1093/infdis/130.4.357. [DOI] [PubMed] [Google Scholar]
- Codner E. C., Maslin W. R. Investigation of renal protein loss in dogs with acute experimentally induced Ehrlichia canis infection. Am J Vet Res. 1992 Mar;53(3):294–299. [PubMed] [Google Scholar]
- Groves M. G., Dennis G. L., Amyx H. L., Huxsoll D. L. Transmission of Ehrlichia canis to dogs by ticks (Rhipicephalus sanguineus). Am J Vet Res. 1975 Jul;36(7):937–940. [PubMed] [Google Scholar]
- Iqbal Z., Chaichanasiriwithaya W., Rikihisa Y. Comparison of PCR with other tests for early diagnosis of canine ehrlichiosis. J Clin Microbiol. 1994 Jul;32(7):1658–1662. doi: 10.1128/jcm.32.7.1658-1662.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Iqbal Z., Rikihisa Y. Reisolation of Ehrlichia canis from blood and tissues of dogs after doxycycline treatment. J Clin Microbiol. 1994 Jul;32(7):1644–1649. doi: 10.1128/jcm.32.7.1644-1649.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kuehn N. F., Gaunt S. D. Clinical and hematologic findings in canine ehrlichiosis. J Am Vet Med Assoc. 1985 Feb 15;186(4):355–358. [PubMed] [Google Scholar]
- Lovering S. L., Pierce K. R., Adams L. G. Serum complement and blood platelet adhesiveness in acute canine ehrlichiosis. Am J Vet Res. 1980 Aug;41(8):1266–1271. [PubMed] [Google Scholar]
- Pierce K. R., Marrs G. E., Hightower D. Acute canine ehrlichiosis: platelet survival and factor 3 assay. Am J Vet Res. 1977 Nov;38(11):1821–1825. [PubMed] [Google Scholar]
- Reardon M. J., Pierce K. R. Acute experimental canine ehrlichiosis. I. Sequential reaction of the hemic and lymphoreticular systems. Vet Pathol. 1981 Jan;18(1):48–61. doi: 10.1177/030098588101800106. [DOI] [PubMed] [Google Scholar]
- Weisiger R. M., Ristic M., Huxsoll D. L. Kinetics of antibody response to Ehrlichia canis assayed by the indirect fluorescent antibody method. Am J Vet Res. 1975 May;36(5):689–694. [PubMed] [Google Scholar]