Investigations into the efficacy of doramectin on reactivated somatic larvae of Ancylostoma caninum Ercolani 1859 (Ancylostomatidae) in pregnant bitches.

The aim of this investigation was to examine whether reactivated somatic Ancylostoma caninum larvae can be eliminated by the administration of doramectin to pregnant bitches. Four pregnant bitches experimentally infected with 20,000 third-stage larvae of A. caninum were treated subcutaneously with 1 mg doramectin per kg body weight on day 55 of the pregnancy (5-8 days before parturition). Another four experimentally infected pregnant bitches served as controls. The single doramectin treatment completely prevented galactogenic infections in the puppies. Neither intestinal stages nor somatic larvae could be found. The administration of doramectin caused no local or generalized side-effects in the bitches. All 16 puppies of the treated bitches were born healthy and remained so during the whole trial period. Beginning during the third week after birth, all 20 puppies of the untreated bitches developed a severe microcytic, hypochromic anaemia. They had to be killed between 17 and 35 days after birth. Post mortem, they revealed a total of 8649 intestinal stages of A. caninum.