POST-THERAPY ANTIBODY-TITERS IN DOGS WITH EHRLICHIOSIS - FOLLOW-UP-STUDY ON 68 PATIENTS TREATED PRIMARILY WITH TETRACYCLINE AND OR DOXYCYCLINE/

The clinical and serological responses to therapy were evaluated for a t least 1 year in 68 dogs with antibody titers positive for Ehrlichia canis. Treatments were of variable periods with primarily tetracycline hydrochloride and/or doxycycline, Sixteen dogs had initial titers of 1:20 and, at the end of the year, were asymptomatic, no longer receivi ng medication, and had negative serology. The average length of treatm ent with tetracycline HCl and/or doxycycline was 85 days (range, 14 to 360 days). Of 39 dogs with initial titers of 1:2,560 or greater, 1 di ed, 25 were asymptomatic, and 13 were lost to follow-up at the end of the study. The average length of treatment was 210 days (range, 21 to 630 days). Twenty-seven dogs were seropositive at greater than or equa l to 1:2,560 when the sera was last tested, Thirteen dogs had initial titers of 1:80 to 1:1,280. Of these 13 dogs, 2 died, 2 were lost to fo llowup, and 9 were asymptomatic and had titers ranging from negative t o greater than or equal to 1:2,560 at the end of the study. The persis tence of antibodies, prolonged subclinical phase, and delayed relapses despite long-term medication, suggest inadequate chemotherapeutic age nts or may be natural features of latency of ehrlichiosis in dogs. Cop yright (C) 1996 by American College of Veterinary Internal Medicine.