A blind test of the serological response of dogs to infection with Taenia ovis.

Fifty six dogs of mixed age and sex were acquired from farms in the Otago/Southland region, and maintained at the Hydatid Research Unit, Taieri, where 43 were each fed two Tueniu ovis cysts. All were bled fortnightly for six or 12 weeks. Coded sera were sent to Wallaceville Animal Research Centre for testing using ELISA, with antigen from T. ovis scoleces. Dog treatments were identified after all tests were complete. A discriminant level was derived from the mean absorbance value plus three standard deviations of 56 sera taken at time zero and 78 sera from serially bled uninfected dogs. None of these 134 sera registered as a false positive using this discriminant level. The data showed no significant deviation from normality, and the expected frequency of the occurrence of false positives is therefore less than 0.14%. Four weeks after infection 63% of dogs proved to be infected were serologically positive, rising to 78% after 6 weeks. When worms were removed by anthelmintic treatment, ELISA absorbance levels decreased. Four weeks after removal 70% of previously infected dogs remained positive, decreasing to 30% after 6 weeks. Six weeks after infection the sensitivity of the test was 78%, and the specificity 63%. However, if dogs with positive ELISA absorbance levels, but which did not purge worms, were regarded as having had worms, the respective figures would be 82% and 100%. The latter figures are similar to our previously published laboratory results. The test is of comparable efficiency to arecoline purgation for surveillance, and has the additional advantage of detecting infection in the majority of those dogs that have been infected for three weeks or more but fail to pass worms on purgation, and a substantial proportion of those infected dogs that were treated by their owners prior to presenting them for purgation in order to avoid detection of infection.

Significance of particle size of mebendazole in the treatment of tapeworm infections.

Taenia hydatigena and Echinococcus granulosus in dogs have been used as a model to evaluate the response of these parasites to increasing doses of mebendazole in different dose forms (powder, micronized powder and tablets of micronized powder). Overall the micronized powder proved to be the most active, the tablets less so and the normal powder least active. Statistical confirmation was obtained that the use of this drug in different dose forms changed the rate of the response, suggesting that in the treatment of human hydatid disease caused by Echinococcus spp and cysticercosis caused by Taenia solium, the dosage form may be a vital factor in the drug's efficacy.

Equine hydatidosis: a new record for New Zealand.

Cysts found in the liver of a horse which had never been out of New Zealand were used to infect two dogs which were slaughtered 35 days after infection. Large numbers of Echinococcus granulosus were recovered. These cestodes were compared with mature dog-sheep cestodes, using light and scanning electron microscopy and identified as the dog-horse strain of E.granulosus.

The effect of route of administration on the efficacy of praziquantel against Echinococcus granulosus infections in dogs.

Dogs infected with Echinococcus granulosus were treated with praziquantel by three routes and at different dosage rates. The results indicated that the dog was of similar efficacy when administered by the oral and intramuscular routes, but less effective by the subcutaneous route.

The effect of nitroscanate tablets of Echinococcus granulosus and Taenia hydatigena infections in dogs.

Tablets of micronised nitroscanate (nominal particle size 2--3 microns) were given to a total of 190 dogs that had been experimentally infected with either Echinococcus granulosus or Taenia hydatigena. The efficiency of the drug in tablet form in freeing dogs from tapeworms, was investigated. The dose rate at which 50 per cent of normally fed dogs can be expected to be freed from E granulosus was found to be 89 mg/kg (95 per cent confidence limits 55 mg/kg to 140 mg/kg). The 90 per cent effective dose rate was not determined within the range 32 mg/kg to 250 mg/kg. The dose rate at which 90 per cent of normally fed dogs can be expected to be freed from T hydatigena was 37 mg/kg (95 per cent confidence limits 23 mg/kg to 60 mg/kg).

The effect of oxfendazole on Echinococcus granulosus and Taenia hydatigena infections in dogs.

Trials with oxfendazole carried out on 120 dogs infected with either Echinococcus granulosus or Taenia hydatigena indicated that a single treatment significantly reduced the proportion of dogs infected with tapeworms. Diarrhoea occurred occasionally when the dose rate exceeded 20 mg/kg.

The effect of mebendazole in food on Echinococcus granulosus and Taenia hydatigena infections in dogs.

A limited, but controlled trial with mebendazole incorporated in a prepared food and with tablets given with this food showed that with the former there was an overall reduction in the expected dog population harbouring Echinococcus granulosus and Taenia hydatigena. Neither treatment was fully effective.

The effect of an antibiotic of the streptothricin family against Echinococcus granulosus and Taenia hydatigena infections in dogs.

The effect of an antibiotic of the streptothricin class on Echinococcus granulosus and Taenia hydatigena infections has been investigated in a trial involving 160 dogs. The drug showed significant activity in freeing dogs from Thydatigena, but the evidence for similar activity against E granulosus was less well marked. Vomiting and diarrhoea were common sequelae of dosing. The preparation tested consisted of four chemical components and the cestocidal value of each was not determined.

The effect of diuredosan on Echinococcus granulosus and Taenia hydatigena infections in dogs.

Diuredosan has been tested against Echinococcus granulosus and Taenia hydatigena infections in dogs. The drug showed significant activity against T hydatigena, but there was no significant dose response curve against E granulosus in this trial. Two treatments at 50 mg/kg or 100 mg/kg, however, reduced the number of dogs infected with hydatid worms. Worms were still present in some dogs after three treatments at 50 mg/kg. Vomiting and diarrhoea were relatively common sequelae at and above 50 mg/kg.

The effect of praziquantel on Echinococcus granulosus, Taenia hydatigena and Taenia ovis infections in dogs.

The effect of praziquantel on Echinococcus granulosus, Taenia hydatigena and T ovis was investigated in a trial involving 360 dogs. The drug was found to be highly toxic to tapeworms. Few dogs remained infected after a single treatment within the range of dose rates tested (0-31 mg/kg to 10-0 mg/kg body weight). No toxicity to dogs was observed.

The lethal effect of some benzimidazoles on Taenia hydatigena in dogs.

The lethal effect of some benzimidazoles on Taenia hydatigena infections in dogs have been compared. Fenbendazole, parbendazole and oxibendazole were more effective than cambendazole and thiabendazole, while coarsely ground mebendazole did not differ significantly from any of them.

The effect of niclosamide on Echinococcus granulosus, Taenia hydatigena and Taenia ovis infections in dogs.

The effect of niclosamide (particle size 1 micron m) and its piperazine salt (particle size 5-10 micron m) on Echinococcus granulosus and Taenia hydatigena has been investigated. The piperazine salt of niclosamide was also tested for activity against Taenia ovis. These trials involved 326 dogs. Irrespective of particle size, the drug was found to be virtually inactive against 28-day-old E granulosus. Some evidence was found indicating that there may be a low degree of activity against 70-day-old worms. The drug was found to be effective at 32 mg/kg and 64 mg/kg against T hydatigena and 50 mg/kg against T ovis. Some evidence was obtained that milk decrease the efficiency of the piperazine salt against T hydatigena at the lower dose rates. Micronisation of the drug did not increase the efficiency against this parasite. Vomiting and diarrhoea were common sequelae.

The effect of micronised nitroscanate on Echinococcus granulosus and Taenia hydatigena infections in dogs.

Trials with micronised nitroscanate carried out on 170 dogs infected with either Echinococcus granulosus or Taenia hydatigena indicated that a single treatment at 62-5 mg/kg and 16 mg/kg respectively significantly reduced the proportion of dogs infected with tapeworms. Some evidence is presented that micronisation may give a fourfold increase in the efficiency of nitroscanate in worm removal without increasing the toxic effects to the dog.

The effect of fospirate on Echinococcus granulosus and Taenia hydatigena infections in dogs.

Trials with fospirate carried out with 170 dogs infected with either Echinococcus granulosus or Taenia hydatigena indicated that a dose rate of 40 mg/kg given on three occasions and 10 mg/kg given on one occasion eliminated each species, respectively. Increasing the dose rat substantially above 40 mg/kg did not reduce the number of treatments required to eliminate all hydatid organisms. Vomiting was observed in some dogs.

The effect of nitroscanate on Echinococcus granulosus and Taenia hydatigena infections in dogs.

Trials with nitroscanate carried out on 186 dogs infected with either Echinococcus granulosus or Taenia hydatigena indicated that a single treatment at a dose rate of 1000 mg/kg or two treatments at 250 mg/kg eliminated the former, but a single treatment at 64 mg/kg was sufficient to eliminate the latter. At this dosing schedule, vomiting and diarrhoea occurred, as well as a transient 'tranquillising' effect on some dogs.

The effect of bithionol sulphoxide on Echinococcus granulosus and Taenia hydatigena infections in dogs.

Trials with bithionol sulphoxide involving 130 dogs, infected with either Echinococcus granulosus or Taenia hydatigena, indicated that a single treatment at a dose rate of 400 mg/kg or two treatments at 50 mg/kg eliminated the former, but a single treatment at 50 mg/kg was sufficient to eliminate the latter. Dose rates 200 mg/kg or more were lethal to some dogs. With two doses of 50 mg/kg, there was only minor discomfort from vomiting or diarrhoea in some dogs.