ABSTRACT
Three cows were repeatedly infected with different strains of Trypanosoma congolense and treated intramuscularly each time with a different dose of diminazene aceturate (Berenil). Biphasic decline was observed of the maximal plasma drug levels, which were attained at 15 min after the first treatment and at 30 min after the second and third treatments. The rate constants for the distribution and terminal phases depended on the period of exposure to parasitaemia of the animal at the time of treatment. Maximal diminazene aceturate residue levels were found in milk 8 h post treatment and declined biexponentially to 4.56 ng ml-1 and 8.76 ng ml-1 at 21 days post treatment after 3.5 mg kg-1 and 7.0 mg kg-1 doses, respectively. In the three cows, higher drug residues were found in the kidney (7.04, 3.92 and 7.99 micrograms g-1) than in liver (3.26, 2.87 and 1.24 micrograms g-1) and heart (1.79, 1.25 and 1.03 micrograms g-1). The results of this study indicate that the level of parasitaemia (degree of anaemia) in the animal at the time of treatment affects the distribution, disposition and elimination of diminazene aceturate in the animal. Furthermore, the residue level in milk after treatment depends on the treatment dose and could easily be bioavailable to the consumer.
Subject(s)
Diminazene/analogs & derivatives , Pregnancy Complications, Parasitic/veterinary , Trypanocidal Agents/pharmacokinetics , Trypanosoma congolense , Trypanosomiasis, Bovine/drug therapy , Animals , Animals, Suckling , Cattle , Diminazene/administration & dosage , Diminazene/blood , Diminazene/pharmacokinetics , Female , Lactation/metabolism , Milk/metabolism , Pregnancy , Pregnancy Complications, Parasitic/drug therapy , Pregnancy Complications, Parasitic/metabolism , Tissue Distribution , Trypanocidal Agents/administration & dosage , Trypanocidal Agents/blood , Trypanosomiasis, African/drug therapy , Trypanosomiasis, African/metabolism , Trypanosomiasis, African/veterinary , Trypanosomiasis, Bovine/metabolismABSTRACT
The effects of bi-weekly flumethrin pour-on treatments at 1 mg kg bodyweight on tsetse fly population and trypanosome infection rates were monitored over a one-year period (2/89-2/90) in 2000 head of cattle on a trial farm, located in the Lamu District in East Kenya, an adjacent control farm and a transsecting road for additional fly monitoring. The tsetse fly population on the trial farm dropped from pretreatment counts of 118 flies/trap/week (Feb. 1989) to 13 in June 1989 and 32 in Jan. 1990. During the same period and months the fly population in the control farm was 90.34 and 87 flies/trap/week. Fly counts on the transsecting road, however, increased from 72.53 to 163 flies/trap/week. The impact of tsetse fly control is clearly reflected in the reduction of trypanosome infection rates on the trial farm, e.g. 37% (pre-treatment infection rate), 10% and 11% in January, June and December 1989 respectively. On the control farm the infection rates remained at distinctly higher levels of 34%, 17% and 24% during the same period. Mean weekly weight gains were 66% higher in the treated herd as compared to the untreated control herd.
