RESUMO
Theileria sp occurs in cattle in Australia where Boophilus microplus is not present. Two species of ixodid ticks namely Haemaphysalis longicornis and H. bancrofti have been implicated as natural vectors. Experimental transmission was obtained with these two species but attempts to transmit the infection with B. microplus, Ixodes holocyclus and Amblyomma triguttatum were not successful. Although calves born in the enzootic area may become infected before one-month-old most show evidence of infection by 5 months of age. Calves born in the winter also become infected earlier than those born at other times of the year.
Assuntos
Apicomplexa/isolamento & purificação , Vetores Aracnídeos/parasitologia , Theileriose/epidemiologia , Carrapatos/parasitologia , Fatores Etários , Animais , Austrália , Sangue/parasitologia , Bovinos , Estações do Ano , Especificidade da Espécie , Theileriose/transmissãoRESUMO
When given to sheep as a single oral dose at 0.1 mg/kg, the B(1a) component of the avermectins caused a reduction of >95% in the numbers of Haemonchus contortus, Ostertagia circumcincta (including inhibited L(4) larvae), Trichostrongylus axei, Trichostrongylus colubriformis, Cooperia oncophora, and Oesophagostomum columbianum. When given to cattle as a single oral dose at 0.1 mg/kg, avermectin B(1a) was >95% effective in reducing the numbers of Haemonchus placei, Ostertagia ostertagi (including inhibited L(4) larvae), T. axei, T. colubriformis, C. oncophora, Cooperia punctata, Oesophagostomum radiatum, and Dictyocaulus viviparus. Avermectin B(1a) was similarly effective, with the exception of a detectable loss in activity against adult C. oncophora, when administered to cattle as a parenteral injection. Some of these ruminant parasites were fully susceptible to dosages of avermectin B(1a) at 0.025 mg/kg, e.g., D. viviparus, O. radiatum, O. ostertagi, and H. contortus. Avermectin B(1a) removed 83 to 100% of Ancylostoma caninum from dogs given a single oral dose of 0.003 to 0.005 mg/kg. The poultry nematodes Capillaria obsignata and immature Ascaridia galli were effectively removed by avermectin B(1a) at 0.05 and 0.1 mg/kg, respectively, but 0.1 mg/kg was not effective for Heterakis gallinarum. Thus, the avermectins would appear to have unprecedented potency and spectrum of biological activity.
Assuntos
Anti-Helmínticos/uso terapêutico , Infecções por Nematoides/tratamento farmacológico , Administração Oral , Animais , Anti-Helmínticos/administração & dosagem , Bovinos , Galinhas , Infecções por Nematoides/parasitologia , Ovinos , Especificidade da EspécieRESUMO
The synthesis and fasciolicidal activity of 4-amino-6-(trichloroethenyl)-1,3-benzenedisulfonamide are reported. A single dose of 15 mg/kg was effective in removing over 90% of immature Fasciola hepatica from sheep (6 weeks after infection) and calves (8 weeks after infection). A 2.5 mg/kg dose removed over 90% of mature (16 weeks old) liver fluke from sheep. Single oral doses up to 400 mg/kg were tolerated by sheep without gross toxic symptoms.
