Efficacy of fluralaner (Bravecto™ chewable tablets) for the treatment of naturally acquired Linognathus setosus infestations on dogs.

BACKGROUND: The clinical efficacy of fluralaner chewable tablets (Bravecto™, MSD Animal Health) against naturally acquired Linognathus setosus infestations on dogs was evaluated compared with permethrin (Exspot®, MSD Animal Health) treatment. METHODS: Privately-owned dogs naturally infested with L. setosus from 21 different households were randomly allocated to two treatment groups. Fourteen dogs were treated once orally with fluralaner and ten dogs were treated once topically with permethrin, at the recommended label dose. Live L. setosus on all dogs were counted before treatment and 1, 7, 28 (both groups) and 84 (fluralaner group) days post-treatment according to a coat parting technique at pre-specified locations and lice species were confirmed microscopically. At the same time points, a veterinary dermatology severity score and an owner's perceived pruritus score were recorded. RESULTS: Percentage reduction in geometric mean L. setosus counts, comparing post- with pre-treatment counts within each group, were 85.7% (day 1), 96.8% (day 7) and 100% (days 28 and 84) for the fluralaner (two-sided two-sample t-test, P ≤ 0.0088 for days 1-84) and 67.5% (day 1), 90.3% (day 7) 99.1% (day 28) for the permethrin group (two-sided two-sample t-test, P ≤ 0.0014 for days 7-28). No lice were seen on fluralaner-treated dogs 28 and 84 days post-treatment. In contrast, two permethrin-treated dogs were re-treated at 7 and 28 days after initial treatment because of observed lice. Owner's perceived pruritus scores were reduced compared to pre-treatment levels by 23.8% (day 1), 31.1% (day 7), 70.4% (day 28) and 99.5% (day 84) after fluralaner treatment and 21.3% (day 1), 45.8% (day 7), and 78.1% (day 28) after permethrin treatment. Dermatological signs were improved compared to pre-treatment levels in both treatment groups. CONCLUSIONS: Single oral fluralaner treatment eliminated natural L. setosus infestation on dogs within 28 days and led to complete dermatological recovery that was maintained until the study end on day 84. Single topical permethrin treatment reduced the number of L. setosus by 99.1% at day 28 although two animals required unscheduled re-treatment.

Proteomic Analyses Reveal the Mechanism of Dunaliella salina Ds-26-16 Gene Enhancing Salt Tolerance in Escherichia coli.

We previously screened the novel gene Ds-26-16 from a 4 M salt-stressed Dunaliella salina cDNA library and discovered that this gene conferred salt tolerance to broad-spectrum organisms, including E. coli (Escherichia coli), Haematococcus pluvialis and tobacco. To determine the mechanism of this gene conferring salt tolerance, we studied the proteome of E. coli overexpressing the full-length cDNA of Ds-26-16 using the iTRAQ (isobaric tags for relative and absolute quantification) approach. A total of 1,610 proteins were identified, which comprised 39.4% of the whole proteome. Of the 559 differential proteins, 259 were up-regulated and 300 were down-regulated. GO (gene ontology) and KEGG (Kyoto encyclopedia of genes and genomes) enrichment analyses identified 202 major proteins, including those involved in amino acid and organic acid metabolism, energy metabolism, carbon metabolism, ROS (reactive oxygen species) scavenging, membrane proteins and ABC (ATP binding cassette) transporters, and peptidoglycan synthesis, as well as 5 up-regulated transcription factors. Our iTRAQ data suggest that Ds-26-16 up-regulates the transcription factors in E. coli to enhance salt resistance through osmotic balance, energy metabolism, and oxidative stress protection. Changes in the proteome were also observed in E. coli overexpressing the ORF (open reading frame) of Ds-26-16. Furthermore, pH, nitric oxide and glycerol content analyses indicated that Ds-26-16 overexpression increases nitric oxide content but has no effect on glycerol content, thus confirming that enhanced nitric oxide synthesis via lower intercellular pH was one of the mechanisms by which Ds-26-16 confers salt tolerance to E. coli.

Ivermectin treatment of free-ranging endangered Australian sea lion (Neophoca cinerea) pups: effect on hookworm and lice infection status, haematological parameters, growth, and survival.

A placebo-controlled study was used to investigate the effectiveness of ivermectin to treat hookworm (Uncinaria sanguinis) and lice (Antarctophthirus microchir) infections in free-ranging Australian sea lion (Neophoca cinerea) pups and to test the hypotheses that these parasitic infections cause anaemia, systemic inflammatory responses, and reduced growth, and contribute towards decreased pup survival. Ivermectin was identified as an effective and safe anthelmintic in this species. Pups administered ivermectin had significantly higher erythrocyte counts and significantly lower eosinophil counts compared to controls at 1-2 months post-treatment, confirming that U. sanguinis and/or A. microchir are causatively associated with disease and demonstrating the positive effect of ivermectin treatment on clinical health parameters. Higher growth rates were not seen in ivermectin-treated pups and, unexpectedly, relatively older pups treated with ivermectin demonstrated significantly reduced growth rates when compared to matched saline-control pups. Differences in survival were not identified between treatment groups; however, this was attributed to the unexpectedly low mortality rate of recruited pups, likely due to the unintended recruitment bias towards pups >1-2 months of age for which mortality due to hookworm infection is less likely. This finding highlights the logistical and practical challenges associated with treating pups of this species shortly after birth at a remote colony. This study informs the assessment of the use of anthelmintics as a tool for the conservation management of free-ranging wildlife and outlines essential steps to further the development of strategies to ensure the effective conservation of the Australian sea lion and its parasitic fauna.

Field efficacy of eprinomectin against the sucking louse Haematopinus asini on naturally infested donkeys.

A trial was conducted to assess the efficacy of eprinomectin (EPR) against the sucking louse Haematopinus asini on naturally infested donkeys. Parasitological investigations were performed on fifteen animals. On day 0, donkeys received EPR pour-on at the manufacturer's recommended cattle dose. Louse counts were performed on days -1, 7, 14, 21, 28, 35, 42, 49 and 56 at seven predilection sites on the skin of each donkey. EPR was completely effective (100%) from day 7, until the end of the study. Clinically no adverse reactions were observed in any of donkeys treated. EPR was considered to be 100% effective against H. asini. This is the first trial to evaluate the efficacy of EPR against a natural louse infestation in donkeys.

Efficacy of spray formulations containing binary mixtures of clove and eucalyptus oils against susceptible and pyrethroid/ malathion-resistant head lice (Anoplura: Pediculidae).

The control efficacy of clove, Eugenia caryophyllata, and eucalyptus, Eucalyptus globulus, essential oils and 15 formulations containing these essential oils alone (8, 12, and 15% sprays) and their binary mixtures (7:3, 5:5, and 3:7 by weight) against adult females of insecticide-susceptible KR-HL and dual malathion- and permethrin-resistant BR-HL strains of head louse, Pediculus humanus capitis (De Geer), was examined by using contact plus fumigant and human hair wig (placed over the head of mannequin) mortality bioassays. In contact plus fumigant mortality bioassay, essential oils from eucalyptus (0.225 mg/cm2) and clove (1.149 mg/cm2) were less effective than either d-phenothrin (0.0029 mg/cm2) or pyrethrum (0.0025 mg/cm2) based on 6-h median lethal concentration values. However, the efficacies of eucalyptus and clove oils were almost identical against females fromn both strains, despite high levels of resistance of the BR-HL females to d-phenothrin (resistance ratio, 667) and pyrethrum (resistance ratio, 754). In human hair wig mortality bioassay, eucalyptus oil spray treatment gave better control efficacy than either spray treatment with clove oil alone or their binary mixtures. Thus, eucalyptus applied as 8% sprays (15 or 20 ml) appears to provide effective protection against pediculosis even to insecticide-resistant head louse populations. Once the safety issues resolved, covering the treated hair and scalp with bath shower cap or hat would ensure the fumigant action of the essential oil.

Therapeutic and persistent efficacy of spinosad applied as a pour-on or a topical spray against natural infestations of chewing and sucking lice on cattle.

Studies were conducted in Wisconsin and Illinois, USA, to assess and compare the therapeutic and persistent efficacy of spinosad when applied as either a pour-on or topical spray and compared with cyfluthrin pour-on and coumaphos topical spray for controlling natural infestations of chewing (Bovicola bovis) and sucking (Linognathus vituli, Solenopotes capillatus and Haematopinus eurysternus) lice on cattle. Thirty-five animals at each trial site were blocked according to pre-treatment lice counts and randomly allocated to one of five treatment groups: single treatments of spinosad (25 g/L), diluted with water to 0.04% active ingredient and applied as a whole-body topical spray; spinosad (25 g/L) applied as a neat pour-on at 2 mg/kg body weight; Co-Ral Emulsifiable Livestock Insecticide (5.8% coumaphos), diluted to 0.03% active ingredient and applied as a whole-body topical spray; CyLence Pour-on Insecticide (1% cyfluthrin), applied as a neat pour-on at the manufacturer's recommended use rate for lice; and untreated control. Both spinosad treatments and cyfluthrin provided > or =96% control of B. bovis for up to 7 weeks, whereas the efficacy of coumaphos dropped to <90% after week 5 at one site. Spinosad spray had the best therapeutic and residual control of all treatments against L. vituli, > or =98% for at least 5 weeks at both sites, compared with 3 weeks for coumaphos at one site. Spinosad and coumaphos sprays provided 100% control of S. capillatus for at least 8 weeks compared with > or =97% control for spinosad and cyfluthrin pour-on treatments over the same interval. While H. eurysternus burden was low and limited to one study site, all four treatments provided 100% control for at least 6 weeks. These studies showed that topically applied spinosad provided a high degree of therapeutic and residual control against both sucking and chewing lice.

Persistent efficacy of doramectin topical solution against induced infestations of Bovicola bovis and Solenopotes capillatus.

A study was conducted in two locations, Wyoming and Wisconsin, USA, to evaluate the persistent efficacy of doramectin topical solution at a dose rate of 500 microg/kg body weight against artificially induced infestations of Bovicola bovis and Solenopotes capillatus on cattle. At each location, lice-free beef calves were individually housed and randomly allocated to treatment. Both B. bovis and S. capillatus were transferred from untreated donor animals to doramectin-treated cattle at the end of 35, 63, 91 or 126 day post-treatment periods. Cattle treated with a saline pour-on served as the control. Based on the geometric means of lice counts 2 weeks following transfer, the persistent efficacy of a single treatment with doramectin topical solution against induced infestations of B. bovis was 100.0, 100.0, 99.5, and 100.0% at post-treatment days of 35, 63, 91, and 126, respectively. Persistent efficacy against induced infestations of S. capillatus, for the same intervals, were 100.0, 94.9, 86.3, and 74.9%.

Systemic activity of nifluridide against sucking lice and the common scabies mite on cattle.

Psoroptes ovis [Hering] mites and sucking lice (Linognathus vituli Linnaeus) were eliminated from light to heavily infested calves with a single subcutaneous injection of nifluridide in five separate experiments. The compound was incorporated in a copolymer vehicle in a sesame oil suspension. In the first two experiments, mites were eliminated within 10 days following a 20 mg kg-1 injection. Eight out of 9 calves were cleared of mites within 7 days post injection of nifluridide at 4, 6 and 9 mg kg-1 in the third experiment. At the end of the 65 day trial, no live mites were isolated from any of the treated animals. In the last two experiments nifluridide eliminated sucking lice populations at all dosage levels. Complete control of the biting lice (Bovicola bovis) was not obtained. No toxic signs were observed in treated calves.

The effect of lice infestation on the growth of Hereford calves.

Two experiments were carried out to examine the effects of cattle lice on the productivity of young calves. In both experiments the main species present was Linognathus vituli. In the first experiment, treatment of grazing heifers and their suckled calves did not improve the overall bodyweight gain of either the heifers or the calves. The calves experienced a rapid build-up in lice populations during autumn and early winter which was associated with mild transient pathogenic effects, but this was followed by an apparent 'self-cure' reaction and compensatory gain during late winter. In the second experiment young calves were placed in feedlots and fed high and low planes of nutrition. Treatment to remove lice did not result in any improvements in growth rate on either plane of nutrition; however it was clear that untreated, undernourished calves had heavier lice infestation.