Prophylactic and therapeutic use of tetracycline during an epizootic of ehrlichiosis among military dogs.

An epizootic of canine ehrlichiosis at the Military Working Dog Center, Pakchong, Thailand, was arrested by prophylactic and therapeutic use of tetracycline and by control of ticks. Oral treatment with tetracycline (66 mg/kg of body weight daily for 14 days) effected remission of signs of disease in 60 of 62 clinically affected dogs and resulted in disappearance of serum antibody in 119 (60%) of 198 seropositive dogs treated during the 2-year study period. Transmission of Ehrlichia canis was interrupted by control of ticks and by daily oral administration of tetracycline at a dosage of 6.6 mg/kg of body weight. When the control program was initiated, 100 (57%) of 174 dogs were seropositive, with one-third of these manifesting clinical signs of ehrlichiosis. The proportion of seropositive reactions progressively decreased to 11% after control was established, and the impact of the disease on health and performance of the dogs was greatly reduced. Eight dogs died before institution of control. Two additional dogs died within the first 2 months after control was established. There was no mortality thereafter.