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Thirty-two pigs were infested experimentally with Sarcoptes scabiei var suis and allocated randomly to a medicated group (injected intramuscularly with 300 micrograms doramectin/kg) or an unmedicated group (injected intramuscularly with 1 ml saline/33 kg). They were observed daily for 15 minutes for signs of pruritus, and the ear lesions were assessed and skin scrapings examined for mites on days 7, 14, 21 and 28 after treatment. In the 16 pigs treated with doramectin the ear lesions resolved completely within 14 days, no mites were recorded on 15 of them on day 7 or on any of them on days 14, 21 and 28; pruritus was greatly reduced from day 7 onwards (range 0 to 0-62 rubbing episodes per pig per day) and papular skin lesions were absent from 15 of the pigs at slaughter on day 28. In comparison, the ear lesions in the 16 unmedicated pigs failed to resolve in 15 of them. Mites were present on 15 of them at different times during the experiment; the numbers of rubbing episodes ranged from 0.88 to 4.65 per pig per day and all the pigs had papular skin lesions at slaughter. In the unmedicated pigs, both the degree of pruritus and the presence and severity of papular skin lesions at slaughter were greater in those with zero or low mite counts than in those with high mite counts.

The efficacy of ivermectin, released intraruminally from a 28-day-delivery device was evaluated in two titration studies against induced infestations of adult Rhipicephalus appendiculatus, R. evertsi and Hyalomma truncatum on cattle. Cattle were given a sufficient number of devices to release ivermectin at approximately 20, 40, 60 or 80 micrograms kg-1 day-1 at a steady-state rate 7-28 days after administration. Tick mortality was recorded, engorged female ticks were weighed and individually incubated, and reproductive data were recorded to determine a reproductive index for the species at various dose levels. Mortality of male and female ticks compared to that of controls was directly related to the daily dose of ivermectin, as was the number of ticks not engorging. Ticks fed on ivermectin-treated cattle had a smaller mass when engorged and laid smaller egg-masses, both absolutely and as a proportion of engorged mass. The index of reproduction of R. appendiculatus was reduced by more than 99.9% at 20 micrograms kg-1 day-1, and the reproductive indices of R. evertsi and H. truncatum were reduced by more than 99.9% at dose rates of 40 micrograms kg-1 day-1 and above. Practical implications of the application of sustained-release ivermectin for the control of multihost ticks and tick-borne diseases are discussed.

The efficacy of triclabendazole (TCBZ) against natural infections with Fasciola gigantica was evaluated in a field study using 102 Indonesian cattle. The animals were divided into two groups; one received TCBZ at 12 mg/kg orally every eight weeks for one year while the other remained untreated. Relative to controls the Fasciola faecal egg count in treated animals was significantly reduced (P less than 0.01) to almost zero at all observations. There were no differences between the groups in blood values and body mass gain. Plasma glutamate dehydrogenase (GLDH) levels in treated animals were reduced to within normal values, whereas those in controls remained above normal throughout. Although plasma gamma glutamyl transferase (GGT) levels remained within the normal range in both groups they were consistently higher in control than in treated animals. However, both GLDH and GGT levels in control animals were considerably lower than those reported by others in experimental low-level chronic fasciolosis, which suggests that only mild liver damage was caused by small numbers of F. gigantica in these animals. In addition to considerations of disease prevalence and economic data from abattoirs, control strategies for fasciolosis in Indonesian cattle require an evaluation of losses due to subclinical disease.

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