Cattle nematodes resistant to macrocyclic lactones: Comparative effects of P-glycoprotein modulation on the efficacy and disposition kinetics of ivermectin and moxidectin

The role of the drug efflux pump, known as P-glycoprotein, in the pharmacokinetic disposition (host) and resistance mechanisms (target parasites) of the macrocyclic lactone (ML) antiparasitic compounds has been demonstrated. To achieve a deeper comprehension on the relationship between their pharmacokinetic and pharmacodynamic behaviors, the aim of the current work was to assess the comparative effect of loperamide, a well-established P-glycoprotein modulator, on the ivermectin and moxidectin disposition kinetics and efficacy against resistant nematodes in cattle. Fifty (50) Aberdeen Angus male calves were divided into five (5) experimental groups. Group A remained as an untreated control. Animals in the other experimental Groups received ivermectin (Group B) and moxidectin (Group C) (200 μg/kg, subcutaneuosly) given alone or co-administered with loperamide (0.4 mg/kg, three times every 24 h) (Groups D and E). Blood samples were collected over 30 days post-treatment and drug plasma concentrations were measured by HPLC with fluorescence detection. Estimation of the anthelmintic efficacy for the different drug treatments was performed by the faecal egg count reduction test (FECRT). Nematode larvae were identified by pooled faecal cultures for each experimental group. Cooperia spp. and Ostertagia spp. were the largely predominant nematode larvae in pre-treatment cultures. A low nematodicidal efficacy (measured by the FECRT) was observed for both ivermectin (23%) and moxidectin (69%) in cattle, which agrees with a high degree of resistance to both molecules. Cooperia spp. was the most abundant nematode species recovered after the different drug treatments. The egg output reduction values increased from 23% to 50% (ivermectin) and from 69% to 87% (moxidectin) following their co-administration with loperamide. Enhanced systemic concentrations and an altered disposition of both ML in cattle, which correlates with a tendency to increased anthelmintic efficacy, were observed in the presence of loperamide. Overall, the in vivo modulation of P-glycoprotein activity modified the kinetic behavior and improved the efficacy of the ML against resistant nematodes in cattle. The work provides further evidence on the high degree of resistance to ML in cattle nematodes and, shows for the first time under field conditions, that modulation of P-glycoprotein may be a valid pharmacological approach to improve the activity and extend the lifespan of these antiparasitic molecules.     

Thelazia callipaeda in Slovakia – From sporadic cases to endemic areas

Spirurid nematode Thelazia callipaeda, transmitted by the fruit fly Phortica variegata, is a causative agent of an ocular parasitic disease called also canine thelaziosis. Dogs, cats, and wild canids are considered the primary definitive hosts for the parasite, but humans may also serve as aberrant definitive hosts. For long decades the geographic range of T. callipaeda was strictly limited to the territory of Asia, but after the year 2000, the parasite began to spread rapidly through Europe. The first autochthonous infections of dogs and foxes in Slovakia were recorded in 2016. In the present study, the results of a whole-area surveillance for canine thelaziosis are reported. Altogether, 142 cases of infection caused by T. callipaeda were diagnosed by veterinarians in dogs between 2016 and the first quarter of 2021, and two cases of feline thelaziosis were recorded. The majority of the dogs showed mild ocular signs manifested by conjunctivitis; 8.5% of them suffered from more serious mucopurulent discharge, and in two dogs corneal ulceration was recorded. The screening revealed increasing trends in the occurrence of canine thelaziosis from both a temporal and spatial point of view and unambiguously confirms the endemic status of T. callipaeda in Slovakia with the prospect of its further expansion.     

Shortened egg reappearance periods of equine cyathostomins following ivermectin or moxidectin treatment: morphological and molecular investigation of efficacy and species composition

Macrocyclic lactones have been the most widely used drugs for equine parasite control during the past four decades. Unlike ivermectin, moxidectin exhibits efficacy against encysted cyathostomin larvae, and is reported to have persistent efficacy with substantially longer egg reappearance periods. However, shortened egg reappearance periods have been reported recently for both macrocyclic lactones, and these findings have raised several questions: (i) are egg reappearance period patterns different after ivermectin or moxidectin treatment? (ii) Are shortened egg reappearance periods associated with certain cyathostomin species or stages? (iii) How does moxidectin’s larvicidal efficacy affect egg reappearance period? To address these questions, 36 horses at pasture, aged 2–5 years old, were randomly allocated to three treatment groups: 1, moxidectin; 2, ivermectin; and 3, untreated control. Strongylid fecal egg counts were measured on a weekly basis, and the egg reappearance period was 5 weeks for both compounds. Strongylid worm counts were determined for all horses: 18 were necropsied at 2 weeks post-treatment (PT), and the remaining 18 at 5 weeks PT. Worms were identified to species morphologically and by internal transcribed spacer-2 (ITS-2) rDNA metabarcoding. Moxidectin and ivermectin were 99.9% and 99.7% efficacious against adults at 2 weeks post treatment, whereas the respective efficacies against luminal L4s were 84.3% and 69.7%. At 5 weeks PT, adulticidal efficacy was 88.3% and 57.6% for moxidectin and ivermectin, respectively, while the efficacy against luminal L4s was 0% for both drugs. Moxidectin reduced early L3 counts by 18.1% and 8.0% at 2 or 5 weeks, while the efficacies against late L3s and mucosal L4s were 60.4% and 21.2% at the same intervals, respectively. The luminal L4s surviving ivermectin treatment were predominantly Cylicocyclus (Cyc.) insigne. The ITS-2 rDNA metabarcoding was in good agreement with morphologic species estimates but suggested differential activity between moxidectin and ivermectin for several species, most notably Cyc. insigne and Cylicocyclus nassatus. This study was a comprehensive investigation of current macrocyclic lactone efficacy patterns and provided important insight into potential mechanisms behind shortened egg reappearance periods.     

Anthelmintic efficacy on UK Thoroughbred stud farms

Anthelmintic drugs have been applied indiscriminately to control horse nematodes for over 40 years. We undertook a comprehensive study to investigate efficacy of the four available broad-spectrum anthelmintic drugs on 16 Thoroughbred stud farms using the faecal egg count reduction test. Efficacy against strongyles was determined by calculating the percentage of reduction in faecal egg count between the group mean at Day 0 and Days 14–17 post-treatment and the 95% lower confidence intervals estimated by non-parametric bootstrapping. Individual strongyle faecal egg count reduction tests (n = 429) were performed in which 179, 131, 89 and 30 horses were administered ivermectin, moxidectin, pyrantel and fenbendazole, respectively. Moxidectin was efficacious in all tests (faecal egg count reduction range: 99.8–100%; 95% lower confidence intervals range: 96.8–100%) and reduced efficacy of ivermectin (faecal egg count reduction range: 85.7–100%; 95% lower confidence intervals range: 65–100%) was observed in one group of yearlings. Reduced pyrantel efficacy was observed in five groups of yearlings (faecal egg count reduction range: 0–73%; 95% lower confidence intervals range: 0–59.5%), but pyrantel was found to be efficacious when administered to mares (faecal egg count reduction range: 98–99.4%; 95% lower confidence intervals range: 91.8–99.3%). Low efficacy of fenbendazole was always observed (faecal egg count reduction range: 0.4–41%; 95% lower confidence intervals not calculable). Two further methods for estimating efficacy were applied and outputs obtained using all methodologies were in agreement. Efficacy against Parascaris equorum was assessed on four farms: fenbendazole had acceptable efficacy (faecal egg count reduction range: 97.5–99.9%; 95% lower confidence intervals range: 96.3–99.1%), but reduced efficacy of ivermectin was observed (faecal egg count reduction range: 25.5–91.2%; 95% lower confidence intervals range: 6.7–82.4%). Strongyle faecal egg count were analysed at approximately 2 week intervals for up to 12 weeks after anthelmintic drug administration to determine the egg reappearance period for moxidectin, ivermectin and pyrantel. The egg reappearance period for all three anthelmintic drugs was shorter than previously observed. Overall, our results indicate that ivermectin and moxidectin administration provided acceptable efficacy at 14 days; however, egg reappearance period results suggest that these products are working less effectively than measured previously. As shortened egg reappearance period is believed to be an early indicator of resistance, this highlights the issue of impending multi-drug resistance in strongyles on stud farms.     

Control of birth in rats by RU 486, an antiprogesterone compound

Rats, isolated at mating (Day 1 of pregnancy), were submitted to either 8 h (8L:16D, Exp. I) or 14 h (14L:10D, Exp. II) of light daily with lights on from 12:00 h to 20:00 h and from 06:00 to 20:00 h respectively. In Exp. I, a single dose of RU 486 (10 mg in 0.2 ml ethanol) was given cutaneously at 08:00 h (Group A1), 12:00 h (Group B1), 19:00 h (Group C1) on Day 21 and at 08:00 h (Group D1) and 12:00 h (Group E1) on Day 22. In Exp. II, the same dose of RU 486 was given at 08:00 h (Group A2), 12:00 h (Group B2) and 19:00 h (Group C2) on Day 21. The solvent was given once at each of the preceding times to the control groups (T1 and T2) in both experiments. Groups T1 and T2 gave birth at two periods, the first on Day 22, the second on Day 23; the proportion of births during each of these periods depended on the light regimen (66.3% in 8L:16D; 50% in 14L:10D on Day 22). The distribution of births in Groups D1 and E1 treated on Day 22 were similar to their controls (T1). Rats treated on Day 21 (Groups A1, A2, B1, B2, C1, C2) gave birth over single periods on Day 22 after an interval correlated with the time of RU 486 administration. The earlier the treatment was given, the higher was the number of dead young and the lower the weight of live young 1 day after birth. These effects of prematurity did not impair further survival rates or weight at weaning.(ABSTRACT TRUNCATED AT 250 WORDS)     

Use of a GnRH agonist to prevent the endogenous LH surge and injection of exogenous LH to induce ovulation in heifers superstimulated with FSH: a new model for superovulation

A new protocol for superovulating cattle which allows for control of the timing of ovulation after superstimulation with FSH was developed. The preovulatory LH surge was blocked with the GnRH agonist deslorelin, and ovulation was induced by injection of LH. In Experiment 1, heifers (3-yr-old) were assigned to a control group (Group 1A, n = 4) or a group with deslorelin implants (Group 1B, n = 5). On Day -7, heifers in Group 1A received a progestagen CIDR-B((R))device, while heifers in Group 1B received a CIDR-B((R))device + deslorelin implants. Both groups were superstimulated with twice daily injections of FSH (Folltropin((R))-V): Day 0, 40 mg (80 mg total dose on Day 0); Day 1, 30 mg; Day 2, 20 mg; Day 3, 10 mg. On Day 2, heifers were given PGF (a.m.) and CIDR-B((R)) devices were removed (p.m.). Three heifers in Group 1A had a LH surge and ovulated, whereas neither of these events occurred in Group 1B (with deslorelin implants) heifers. In Experiment 2, heifers (3-yr-old) were assigned to 1 of 4 equal groups (n = 6). On Day -7, heifers in Group 2A received a norgestomet implant, while heifers in Groups 2B, 2C and 2D received norgestomet + deslorelin implants. Heifers were superstimulated with FSH starting on Day 0 as in Experiment 1. On Day 2, heifers were given PGF (a.m.) and norgestomet implants were removed (p.m.). Heifers in Groups 2B to 2D were given 25 mg LH (Lutropin((R))): Group 2B, Day 4 (a.m.); Group 2C, Day 4 (p.m.); Group 2D, Day 5 (a.m.). Heifers in Group 2A were inseminated at estrus and 12 and 24 h later, while heifers in Groups 2B to 2D were inseminated at the time of respective LH injection and 12 and 24 h later. Injection of LH induced ovulation in heifers in Groups 2B to 2D. Heifers in Group 2C had similar total ova and embryos (15.2 +/- 1.4) as heifers in Group 2A (11.0 +/- 2.8) but greater (P < 0.05) numbers than heifers in Group 2B (7.0 +/- 2.3) and Group 2D (6.3 +/- 2.0). The number of transferable embryos was similar for heifers in Group 2A (5.8 +/- 1.8) and Group 2C (7.3 +/- 2.1) but lower (P < 0.05) for heifers in Group 2B (1.2 +/- 0.8) and Group 2D (1.3 +/- 1.0). The new GnRH agonist-LH protocol does not require observation of estrus, and induces ovulation in superstimulated heifers that would not have an endogenous LH surge.     

Shedding of feline lungworm larvae and their infectivity to snail intermediate hosts after anthelmintic treatment

Aelurostrongylus abstrusus and Troglostrongylus brevior are snail-transmitted helminths causing respiratory diseases in infected cats. The shedding of feline lungworm L1s and their infectivity to the snail intermediate host, after administration of anthelminthic products to cats, are poorly documented. To assess the efficacy of 8.3% fipronil, 10% (S)-methoprene, 0.4% eprinomectin and 8.3% praziquantel (i.e. eprinomectin formulation) and 10% imidacloprid/1% moxidectin (i.e. moxidectin formulation) against these nematodes and to determine the number of days post-treatment until viable L1s are released in the faeces, 384 animals were screened by faecal examination. Of the 54 positive animals (i.e., 14.1%; 7.3% A. abstrusus, 6.2% T. brevior and 0.5% coinfected), 36 were randomly allocated to four groups. Groups A and B were composed of cats positive for T. brevior and treated with the eprinomectin and with the moxidectin formulations, respectively, whereas cats in groups C and D were positive to A. abstrusus and treated with the eprinomectin and the moxidectin formulations, respectively. Prior to and every day after treatment, faecal samples were analysed by the Baermann technique and the number of larvae per gram of faeces determined, and again four weeks after treatment, to assess the efficacy of a single administration of the products. In addition, to evaluate the pre- and post-treatment infectivity of L1s to snail intermediate hosts, one/two snails per cat were infected with 100 L1s collected from the faeces of enrolled animals and then digested 28 days p.i. Based on L1s faecal counts, the efficacy of the eprinomectin and the moxidectin formulations at 28 days was 100% for both A. abstrusus and T. brevior, with a mean number of days of 7.9 ± 1.2 in group A, 7.8 ± 1.9 in B, 6.9 ± 1.6 in C and 8.9 ± 2.0 in D to become negative. Following the artificial digestion, active L3s of T. brevior and A. abstrusus were found in 160 (87.4%) experimentally infected snails. The results of this study demonstrate that a single administration of the two formulations is effective in the treatment of A. abstrusus and T. brevior infections and that during the post-treatment period live L1s are shed for up to 8.9 ± 2.0 days. L1s of both lungworm species released in the faeces after drug administration are still able to reach the infective larval stage in the infected snails. Hence, preventative measures after the treatment of infected animals should include keeping cats indoors and disposal of their faeces for approximately 10 days to avoid environmental contamination and infection of gastropod intermediate hosts.     

The Welfare Consequences and Efficacy of Training Pet Dogs with Remote Electronic Training Collars in Comparison to Reward Based Training

This study investigated the welfare consequences of training dogs in the field with manually operated electronic devices (e-collars). Following a preliminary study on 9 dogs, 63 pet dogs referred for recall related problems were assigned to one of three Groups: Treatment Group A were trained by industry approved trainers using e-collars; Control Group B trained by the same trainers but without use of e-collars; and Group C trained by members of the Association of Pet Dog Trainers, UK again without e-collar stimulation (n = 21 for each Group). Dogs received two 15 minute training sessions per day for 4–5 days. Training sessions were recorded on video for behavioural analysis. Saliva and urine were collected to assay for cortisol over the training period. During preliminary studies there were negative changes in dogs'' behaviour on application of electric stimuli, and elevated cortisol post-stimulation. These dogs had generally experienced high intensity stimuli without pre-warning cues during training. In contrast, in the subsequent larger, controlled study, trainers used lower settings with a pre-warning function and behavioural responses were less marked. Nevertheless, Group A dogs spent significantly more time tense, yawned more often and engaged in less environmental interaction than Group C dogs. There was no difference in urinary corticosteroids between Groups. Salivary cortisol in Group A dogs was not significantly different from that in Group B or Group C, though Group C dogs showed higher measures than Group B throughout sampling. Following training 92% of owners reported improvements in their dog''s referred behaviour, and there was no significant difference in reported efficacy across Groups. Owners of dogs trained using e-collars were less confident of applying the training approach demonstrated. These findings suggest that there is no consistent benefit to be gained from e-collar training but greater welfare concerns compared with positive reward based training.     

Efficacy of moxidectin for the prevention of adult heartworm (Dirofilaria immitis) infection in dogs

The authors report the efficacy of orally administered moxidectin for the prevention of canine heartworm infection in two endemic areas in northern Italy. Two trials were conducted on a total of 257 dogs, including 137 treated with moxidectin (minimum dose of 3 mcg/kg body weight), 85 with ivermectin (minimum dose 6.6 mcg/kg b.w.) and 35 untreated controls. Results of testing for microfilariae and circulating adult female antigens were negative for all treated dogs at the end of both trials. No adverse reactions to moxidectin were observed. In the study areas, prevalence values for Dirofilaria immitis infection calculated on the basis of the untreated controls and testing dogs which had no preventive treatment in the previous transmission season ranged 23-65%. This study confirms the efficacy and safety of moxidectin in the prevention of adult heartworm infection in dogs.     

ABC transporters influence sensitivity of Brugia malayi to moxidectin and have potential roles in drug resistance

Some ABC transporters play a significant role in human health and illness because they confer multidrug resistance (MDR) through their overexpression. Compounds that inhibit the drug efflux mechanism can improve efficacy or reverse resistance. Of the eight described ABC transporter subfamilies, those proteins conferring MDR in humans are in subfamilies A, B, C, and G. In nematodes, transporters in subfamilies B and C are suggested to confer resistance to ivermectin. The Brugia malayi ABC transporter superfamily was examined to assess their potential to influence sensitivity to moxidectin. There was an increase in expression of ABC transporters in subfamilies A, B, C, and G following treatment. Co-administration of moxidectin with inhibitors of ABC transporter function did not enhance sensitivity to moxidectin in males; however, sensitivity was significantly enhanced in females and microfilariae. The work suggests that ABC transporters influence sensitivity to moxidectin and have a potential role in drug resistance.     

Essential role of magnesium ion in water for colonization of Helicobacter pylori in 2-week-old miniature pigs

This study was designed to determine whether magnesium ion in water would influence the colonization of Helicobacter pylori in 2-week-old miniature pigs. Groups A (2 pigs) and B (1 pig) were both fed a milk diet dissolved in drinking water, Group C (2 pigs) was fed a milk diet dissolved in deionized distilled water (DDW), and Group D (1 pig) was fed a milk diet dissolved in DDW supplemented with MgCl2. Groups B, C, and D were all challenged with H. pylori, and Group A was not. Necropsy was performed on the pigs on postinfection Day 5, and biopsy specimens were taken from 16 sites of the stomach. H. pylori were recovered from 11 of 16 sites in Group B, 1 of 32 sites in Group C, and 13 of 16 sites in Group D. On the other hand, the degree of lymphocyte infiltration increased in the order of Group A < Group B < Group C < Group D. These observations suggest that magnesium ion in drinking water is essential for the colonization of H. pylori in the pig stomach. Possible mechanisms for the lymphocyte infiltration are discussed.     

Serum CRP Protein as a Differential Marker in Cancer

The objective of this study was to measure the serum concentrations of C-reactive protein (CRP) in cancer patients and compare with those of immune disease patients and healthy individuals for discriminatory analysis. For this purpose, automatic systems for special protein analysis (Type: Drcon Diognostica Tarbox) was used to measure serum CRP concentrations in 276 cancer patients (Group A), 110 immune disease patients (Group B), 161 phlogistic patients (Group C), and 125 age-matched healthy individuals (Group D). Our data show that serum CRP concentrations in Group A were significantly higher than those in Groups B and D, whereas CRP concentrations in Group B were higher than those in Group D. The differences of serum CRP concentrations between Groups A and B as well as between Groups B and D were significant (P?<?0.01). We, therefore, concluded that the measurement of serum CRP concentrations was a fast and accurate method to distinguish between cancer and immune disease patients.     

Genital lesions in male red fronted gazelles (Gazella rufifrons) experimentally infected with Trypanosoma brucei and the effect of melarsamine hydrochloride (Cymelarsan®) and diminazene aceturate (Berenil®) in its treatment

Thirty red fronted gazelles (Gazella rufifrons) were used to assess the genital lesions associated with trypanosomosis and the efficacy of melarsamine hydrochloride (Cymelarsan^®) and diminazene aceturate (Berenil^®) in the treatment of the condition. The animals were divided into 6 equal groups (A-F). Animals in groups A-E were infected with Trypanosoma brucei, and later treated on day 8 post infection (p.i.) with either melarsamine hydrochloride (Cymelarsan^®) at 0.3 mg/kg (Group A) and 0.6 mg/kg (Group B) or diminazene aceturate (Berenil^®) at 3.5 mg/kg (Group C) and 7.0 mg/kg (Group D). Animals in group E remained untreated while group F served as healthy controls. Parasitaemia was established by day 8 p.i. in all infected groups and eliminated by day 16 following treatment on day 8 p.i. with melarsamine hydrochloride (Cymelarsan^®) (Groups A and B) or diminazene aceturate (Berenil^®) (Group D). On the other hand, diminazene aceturate treatment (Berenil^®) on day 8 p.i. at 3.5 mg/kg (Group C) caused a temporary disappearance of parasites from the circulation by day 16 p.i. but there was a relapse parasitaemia on day 44 with a peak count of 500 ± 2.79 × 10³ parasites/μL of blood by day 52 p.i. In the infected/untreated group (E), parasitaemia fluctuated but attained the same peak as Group C by day 52 p.i. Increase in body temperatures (40.5 ± 3.16 - 42.8 ± 3.25 °C) occurred during the first wave of parasitaemia but declined to pre-infection values from day 28 p.i. in Groups A, B and D. In Groups C and E, there was a second wave of parasitaemia (P < 0.05) with peak counts of 42.4 ± 0.81 × 10³/μL and 41.8 ± 0.80 × 10³/μL respectively by day 52 p.i. A significant (P < 0.05) decline in packed cell volume was also noted by day 52 p.i. The major clinical signs observed in Groups C and E were pyrexia, inappetance, emaciation, anaemia, dullness, starry hair coat, pallor of buccal and ocular mucous membranes. Similarly, in Groups C and E, the testicles appeared oedematous and painful to touch with degenerative changes, morphological sperm abnormalities and oligospermia with 2.0% and 0% sperm reserves respectively. Sperm reserve was 100% in Groups A, B and D. It is therefore, concluded that trypanosomosis can cause serious infertility in male red fronted gazelles and that early treatments with melarsamine hydrochloride (Cymelarsan^®) at 0.3 and 0.6 mg/kg body weight or diminazene aceturate (Berenil^®) at 7.0 mg/kg body weight may prevent such effects.     

Follicular growth, ovulation and embryo recovery in dairy cows given FSH at the beginning or middle of the estrous cycle

Variability in the superovulation response is an important problem for the embryo transfer industry. The objective of this study was to determine whether FSH treatment at the beginning of the cycle would improve the ovulation rate and embryo yield in dairy cows. Twenty-eight postpartum cyclic dairy cows were allocated at random to 4 treatment groups (A, B, C and D). Group A cows (n = 10) received FSH (35 mg) at a decreasing dose, starting on Day 9 (Day 0 = day of estrus) for 5 days followed by PGF(2alpha) (35 mg) on Day 12. Cows assigned to Groups B, C and D (n = 6 cows each, respectively) were given 35 mg FSH at a decreasing dose from Days 2 to 6 followed by PGF(2alpha) on Day 7. Group C and D cows received PRID inserts from Day 3 to Day 7. Cows in Group D additionally received 1000 IU hCG 60 hours after PGF(2alpha) treatment. Ovaries were scanned daily using a real time ultrasound scanner from the beginning of FSH treatment until embryo recovery, to monitor follicular development, ovulation and the number of unovulated follicles. Embryos were recovered from the uterus by a nonsurgical flushing technique 7 days after breeding. There were no differences (P>0.01) in the number of follicles > 10 mm at 48 hours after PGF(2alpha) treatment among the 4 groups. The mean numbers of follicles were 10.6 +/- 1.2, 9.3 +/- 1.3, 12.2 +/- 1.3 and 15.0 +/- 2.9 for Groups A, B, C and D, respectively. A significantly (P<0.001) higher number of ovulations was observed and a larger number of embryos was recovered in Group A than in the other groups. The results of this study indicate that superovulation with FSH at the beginning of the cycle causes sufficient follicular development but results in very low ovulation and embryo recovery rates.     

Persistent efficacy of long-acting moxidectin for control of trichostrongylid infections of sheep

The objective was to evaluate long-acting moxidectin (Cydectin^® 2% LA for sheep) against trichostrongylids in sheep. We performed a blocked, parallel, controlled clinical trial. We included 45 ewe-lambs, allocated into treated (n = 30, 1.0 mg moxidectin per kg bw, subcutaneously at base of ear on D 0) or controls (n = 15). Animals had been naturally infected (pre-treatment geometric mean epg counts: 233 and 249, respectively) and throughout the study grazed at the same pasture. Fortnightly, we collected faecal samples and performed established parasitological techniques (epg counts, coprocultures). We used analysis of covariance for post-treatment results, using pre-treatment counts as covariate, treatment as fixed effect, block as random effect. Geometric mean epg counts in treated animals were 0 up to D 112, 1 on D 126, 4 on D 140 and 13 on D 161. Respective figures for controls were 369–820 up to D 140 and 168 on D 161 (p < 0.05). Persistent efficacy (>90%) was 140 d for Teladorsagia, 119 d for Haemonchus and 115 d for Trichostrongylus. This is the first reported clinical trial of efficacy of long-acting moxidectin in sheep in Europe. Cydectin 2% LA was found to be effective against trichostrongylids of sheep. The particularly long persistent efficacy can provide new possibilities in formulating anthelmintic programs for sheep.     

Capillaria plica (syn. Pearsonema plica) infection in a dog with chronic pollakiuria: Challenges in the diagnosis and treatment

Capillaria plica (syn. Pearsonema plica) is a nematode parasite of the urinary tract of canids, felids and mustelids, which can cause cystitis, pollakiuria, dysuria and hematuria. An eight-month-old female crossbred dog from Switzerland presented a six-month history of frequent urination. During the first clinical examination, C. plica eggs were detected in the urine sediment. Three series of treatments with fenbendazole (50 mg/kg body weight [BW]/day, orally) for 10 days each, three single day treatments with moxidectin–imidacloprid (spot-on) and one single administration of ivermectin (0.2 mg/kg BW subcutaneously) were performed within an eight-month period. None of those treatments succeeded in eliminating the C. plica infection or in resolving the clinical signs. An endoscopic examination of the urine bladder still revealed numerous adult viable C. plica worms attached to the bladder mucosa. A two-day treatment with levamisole (7.5 mg/kg BW/day intramuscularly) was subsequently performed. An endoscopic control of the urine bladder two days after this treatment and a urine analysis after two weeks confirmed the elimination of the parasites. The clinical signs disappeared within one month. Levamisole was shown to be effective against C. plica infection in a dog, whereas previous treatments with fenbendazole, moxidectin and ivermectin had failed.     

A Randomized,Single-Ascending-Dose,Ivermectin-Controlled,Double-Blind Study of Moxidectin in Onchocerca volvulus Infection

Background

Control of onchocerciasis as a public health problem in Africa relies on annual mass ivermectin distribution. New tools are needed to achieve elimination of infection. This study determined in a small number of Onchocerca volvulus infected individuals whether moxidectin, a veterinary anthelminthic, is safe enough to administer it in a future large study to further characterize moxidectin''s safety and efficacy. Effects on the parasite were also assessed.

Methodology/Principal Findings

Men and women from a forest area in South-eastern Ghana without ivermectin mass distribution received a single oral dose of 2 mg (N = 44), 4 mg (N = 45) or 8 mg (N = 38) moxidectin or 150 µg/kg ivermectin (N = 45) with 18 months follow up. All ivermectin and 97%–100% of moxidectin treated participants had Mazzotti reactions. Statistically significantly higher percentages of participants treated with 8 mg moxidectin than participants treated with ivermectin experienced pruritus (87% vs. 56%), rash (63% vs. 42%), increased pulse rate (61% vs. 36%) and decreased mean arterial pressure upon 2 minutes standing still after ≥5 minutes supine relative to pre-treatment (61% vs. 27%). These reactions resolved without treatment. In the 8 mg moxidectin and ivermectin arms, the mean±SD number of microfilariae/mg skin were 22.9±21.1 and 21.2±16.4 pre-treatment and 0.0±0.0 and 1.1±4.2 at nadir reached 1 and 3 months after treatment, respectively. At 6 months, values were 0.0±0.0 and 1.6±4.5, at 12 months 0.4±0.9 and 3.4±4.4 and at 18 months 1.8±3.3 and 4.0±4.8, respectively, in the 8 mg moxidectin and ivermectin arm. The reduction from pre-treatment values was significantly higher after 8 mg moxidectin than after ivermectin treatment throughout follow up (p<0.01).

Conclusions/Significance

The 8 mg dose of moxidectin was safe enough to initiate the large study. Provided its results confirm those from this study, availability of moxidectin to control programmes could help them achieve onchocerciasis elimination objectives.

Trial Registration

ClinicalTrails.gov NCT00300768     

Effect of propofol on mitochondrial ATP content and ATPase activity in hippocampus of rats with cerebral ischemia-reperfusion injury

ObjectiveStudy on the influence of the cerebral Ischemia-reperfusion Injury (IRI) on mitochondrial adenosine triphosphate (ATP) content and ATPase activity in hippocampus of rats, as well as the protective effect of propofol on IRI in rats.MethodsA total of 40 male SD rats were randomly divided into 5 groups: sham operation group (Group A), ischemia reperfusion control group (Group B) and ischemic reperfusion with propofol pretreatment group (C group). Group C was further divided into three sub groups according to the different doses of propofol: Group C1 (50 mg/kg), Group C2 (100 mg/kg) and Group C3 (150 mg/kg). The rats from Groups B and C were applied for the IRI model preparation by blockage of the blood flow in arteria carotis communis. For the Groups A, arteria carotis communis were separated without blockage of the blood flow. Before preparation of IRI model for rats in Group C, different doses of propofol were intraperitoneally injected into the rats. For rats in Groups A and B, only saline solution with same volume was intraperitoneally injected at the same time. The ultra-structures of mitochondria in hippocampus of rats were observed under transmission electron microscope, and the mitochondrial degeneration rate was counted. The contents of ATP were determined by HPLC and the ATPase activity was characterized by ATPase activity assay kit.Results(1) Mitochondria in the hippocampus from Groups B and C showed different degrees of ultrastructural damage and more significant mitochondrial degeneration than those from Group A. The degree of damage and the rate of degeneration were in the order of B > C1 > C2 > C3 and the difference was statistically significant (P < 0.01). (2) The contents of ATP and the ATPase activity in hippocampus from Groups B and C were significantly lower than those of Group A, while these indices from Group C were significantly higher than those in the B group, and the sequence was C3 > C2 > C1, indicating that the ATP content and ATPase activity were significantly correlated with the dose of propofol, and the difference was statistically significant (P < 0.05).ConclusionIn summary, the contents of ATP and ATPase activity in hippocampus of rats can be decreased by cerebral IRI. The structure and function of the impaired mitochondria in IRI rats could be significantly improved by propofol, and the improvement effect is related to the dose of propofol.     

Effectiveness of prostaglandin F2alpha in the initial treatment of bovine ovarian cysts

This study was conducted to evaluate the use of prostaglandin F2alpha (PGF2alpha) in the initial treatment of ovarian cysts in dairy cattle. Two hundred and sixty three cows diagnosed cystic on palpation per rectum were randomly assigned to one of three treatment groups (A, B or C). Cows in Groups A and B were treated with 25 mg i.m.of PGF2alpha at the time of diagnosis (Day 0), while cows in Group C received 100 mug of GnRH. Seven days following initial treatment (Day 7), cows from Group A that were not observed in estrus were treated with GnRH. Cows from Groups B and C were not treated. On Day 14, all cows that had not been inseminated received PGF2alpha. A blood sample was obtained from all cows on Days 0, 7 and 14 and was analyzed for progesterone (P4) using radioimmunoassay. Incidences of estrus were recorded and cows that were more than 60 d in milk at the time of diagnosis were bred when observed in estrus. The incidence of follicular cysts on Day 0 (as defined as P4 <0.5 ng/ml) was similar between groups and constituted about 40% of all cysts. There were significantly more cows pregnant to insemination within 7 d of initial treatment in Group B than in Groups A and C (P<0.05). After Day 14, the pregnancy rate was not statistically different between Group B and C, but Groups B and C had a statistically higher pregnancy rate than Group A from Day 21 to Day 35. At the end of the study, there was no statistical difference for the pregnancy rate between groups. We concluded that treatment of ovarian cysts diagnosed by per rectum examination with prostaglandin (at time of diagnosis and 14 d later for cows that were not inseminated) was as effective as initial treatment with GnRH followed by prostaglandins 14 d later for cows that were not inseminated previously. Cows that were initially treated with prostaglandins also tended to become pregnant sooner.     

Dosage response evaluation of luprostiol administered to pregnant sows

Two trials were completed to investigate the effects of luprostiol in swine. The first trial was to evaluate parturition induced by various dosages of luprostiol compared with those of lutalyse or vehicle. Sows were assigned by random allotment to one of the following treatments on Day 112 of gestation: Group A, control (0 mg luprostiol); Group B (1.88 mg luprostiol); Group C (3.75 mg luprostiol); Group D (7.5 mg luprostiol); Group E (15 mg luprostiol); Group F (10 mg lutalyse). All prostaglandin-treated groups farrowed earlier than the controls (P<0.05), with Groups D (26.3 h), E (31.0 h) and F (25.8 h) having the shortest treatment-to-first-pig intervals, and Groups A (76.0 h), B (54.4 h) and C (40.0 h) having the longest intervals. Luprostiol-treated sows had the shortest farrowing time (P<0.05; range = 3.2 to 3.9 h). Significant differences were found for the time (min) between births: Group A (32.1), Group B (28.4), Group F (35.5) took longer than Group C (20.2), Group D (21.0) and Group E (21.6). In a second trial, 20 crossbred pregnant sows received either vehicle or luprostiol (7.5 mg) on Day 112 of gestation. Progesterone concentrations declined rapidly (P<0.05) in luprotiol treated females but were unchanged in control females during the 24-h collection period. The results of these trials show 7.5 mg luprostiol to be the most effective dose for inducing farrowing.