Treatment of Taenia hydatigena infections in dogs with-bunamidine hydroxynaphthoate incorporated in food

Abstract

Extract

Theoretically, the life-cycle of the sheep metacestodes with their strobilate phase in dogs permits combinations of at least three methods of control. These are the prevention of dogs gaining access to larval cestodes, the chemical elimination of the strobilate and or the larval stage in the appropiate hosts, and the immunization of either the definitive or intermediate hosts or both. The first approach using arecoline hydrobromide primarilv as a diagnostic agent has reduced the prevalence of Echinococcus granulosus (Gemmell, 1968 Gemmell, M. A. 1968. The Styx field-trial. A study on the application of control measures against hydatid disease caused by Echinococcus granulosus. Bull. Wld Hlth Org., 39: 73–100.  [Google Scholar]). However, it did not markedly reduce the prevalence rate of Taenia hydatigena and may have been indirectly associated with an increase in that of Taenia ovis.     

Efficacy of praziquantel against ovine cysticercosis caused by Taenia hydatigena

Praziquantel was evaluated for its larvicidal activity against naturally or experimentally induced Taenia hydatigena infections in sheep. The major criterion used for assessing efficacy was an estimate of the dose rate required to free 90 per cent of the sheep from infection (ED90) together with a 95 per cent confidence interval. With both light and heavy infections of three-month-old T hydatigena in lambs up to 12 months old, many larvae were killed. The ED90 and 95 per cent confidence limits for six-month-old and aged organisms was estimated to be 13.1 (5.5 to 31.4) mg/kg and 6.1 (2.4 to 15.5) mg/kg, respectively. Equivalent data for the ED50 were 3.4 (1.4 to 8.3) mg/kg and 1.3 (0.3 to 5.4) mg/kg, respectively. It was established that one of the factors involved in the efficacy of praziquantel was associated with the age of the larvae at the time of treatment, the drug being markedly more effective against older than younger organisms.     

Effectiveness of a non-surgical alternative to the Mules operation in sheep

Objective To measure changes to the perineal bare area, local tissue reaction and healing responses of young sheep, following intradermal administration of cetrimide and polyvinylpyrrolidone (PVP), with and without ethanol, to the breech and tail. Method A needle‐less injector was used to deposit formulations containing 40 g/L cetrimide and 30 g/L PVP (group 2) or 20 g/L cetrimide, 30 g/L PVP and 15 g/L ethanol (group 3), within the dermis of the tail and the region surrounding the perineal bare breech area of groups (N = 8) of Merino weaner sheep. The dimensions of the perineal bare area (length, width and diagonal distances left and right) and tail width were recorded before and at intervals after treatment for 60 days. Observations of swelling and bruising and scab formation at the treatment sites were recorded for up to 35 days after treatment. Rectal temperatures were monitored for up to 35 days after treatment and bodyweight for up to 60 days after treatment. An untreated control group (group 1) was included. Results Comparison of day ‐3 and day 35 measurement data showed that both treated groups had significantly (P < 0.05) wider breech bare areas compared to the untreated controls and that group 2 sheep had significantly (P < 0.05) longer breech bare areas compared to group 3 sheep or to the untreated controls, which were not significantly different. At this time scabs were still firmly in place on many treated sheep. At day 35 there was no increase in tail bare area caused by either treatment. By day 60 there was no significant difference between the treated and control groups in either the breech or tail regions indicating that the changes present at day 35, were not permanent. Mean weight gain in the groups throughout the 60‐day interval was unaffected by treatment. Intradermal treatment was associated with a significant elevation in body temperature. This effect lasted for 3 days and was associated with signs of discomfort and depressed appearance in at least some of the treated sheep. Bruising was mild to severe in all treated sheep within two days of treatment but was not evident in any sheep by day 21. Mild to moderate swelling was also associated with treatment but was not uniform across sheep in the groups. The tail of one sheep was severely swollen for several days. Swelling remained obvious in most treated sheep until day 14 but was not present at day 21. Conclusion Under the conditions of this study intradermal injection of cetrimide had no permanent effect on bare area measurements on the breech or the amount of wool‐bearing skin on the tail. It also caused signs of discomfort and pain that raise welfare concerns.     

Efficacy of a drug combination of praziquantel, pyrantel embonate, and febantel against helminth infections in dogs.

Tablets containing praziquantel, pyrantel embonate, and febantel were tested for efficacy against helminths in dogs. A single treatment with this drug combination gave 100% reductions in Toxocara canis and Taenia hydatigena in experimentally induced infections in dogs. In dogs with naturally acquired infections, treatment gave > 97 to 98% reductions in fecal egg counts attributable to Toxascaris leonina, T canis, and Uncinaria stenocephala. Efficacy against Trichuris vulpis was > 92%.     

Coenurosis in New Zealand

Extract

Sir,—During the survey on the cestode problems of food animals and dogs in New Zealand, Multiceps multi-cops (Leske, 1780) and its metacestode Coenurus cerebralis have been observed in the dog and sheep respectively in mid-Canterbury. An unconfirmed case has also been reported recently in a lamb's brain exported to Australia.     

Ergovaline does not alter the severity of ryegrass staggers induced by lolitrem B

AIM: To investigate a possible interaction between lolitrem B and ergovaline by comparing the incidence and severity of ryegrass staggers in sheep grazing ryegrass (Lolium perenne) containing lolitrem B or ryegrass containing both lolitrem B and ergovaline.

METHODS: Ninety lambs, aged approximately 6 months, were grazed on plots of perennial ryegrass infected with either AR98 endophyte (containing lolitrem B), standard endophyte (containing lolitrem B and ergovaline) or no endophyte, for up to 42 days from 2 February 2010. Ten lambs were grazed on three replicate plots per cultivar. Herbage samples were collected for alkaloid analysis and lambs were scored for ryegrass staggers (scores from 0–5) weekly during the study. Any animal which was scored ≥4 was removed from the study.

RESULTS: Concentrations of lolitrem B did not differ between AR98 and standard endophyte-infected pastures during the study period (p=0.26), and ergovaline was present only in standard endophyte pastures. Ryegrass staggers was observed in sheep grazing both the AR98 and standard endophyte plots, with median scores increasing in the third week of the study. Prior to the end of the 42-day grazing period, 22 and 17 animals were removed from the standard endophyte and AR98 plots, respectively, because their staggers scores were ≥4. The cumulative probability of lambs having scores ≥4 did not differ between animals grazing the two pasture types (p=0.41).

CONCLUSIONS AND CLINICAL RELEVANCE: There was no evidence for ergovaline increasing the severity of ryegrass staggers induced by lolitrem B. In situations where the severity of ryegrass staggers appears to be greater than that predicted on the basis of concentrations of lolitrem B, the presence of other tremorgenic alkaloids should be investigated.     

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.