Efficacy and Safety of a Permethrin-Fipronil Spot-On Solution (Effitix®) in Dogs Naturally Infested by Ticks in Europe.

Effitix is a new broad spectrum product based on the combination of fipronil 6.1% and permethrin 54.5% in a solution for spot-on application. It has been shown to be safe and efficacious in dogs in controlling tick, flea, sandfly, and mosquito infestations in laboratory conditions. The aim of this controlled, randomised study was to assess its safety and efficacy against natural tick infestations in field conditions. One hundred eighty-two privately owned dogs were included in France and Germany: 123 dogs were treated on day 0 with the permethrin-fipronil combination (Effitix) and 59 with a permethrin-imidacloprid combination (Advantix®). Tick counts were conducted on days 0 (before treatment), 7, 14, 21, and 28. The percentages of efficacy on days 7, 14, 21, and 28 were, respectively, 91.2%, 97%, 98.3%, and 96.7% with Effitix and were 94.8%, 96.9%, 95.7%, and 94.6% with Advantix. Very few adverse events were reported. Most were not serious and/or not related to the treatment with pruritus being the most common. One administration of Effitix was highly effective and safe to treat and control tick infestations for four weeks in field conditions and had a similar efficacy as the permethrin-imidacloprid combination for all visits.

Efficacy of a single dose of milbemycin oxime/praziquantel combination tablets, Milpro(®), against adult Echinococcus multilocularis in dogs and both adult and immature E. multilocularis in young cats.

Two single-site, laboratory, negatively controlled, masked, randomised dose confirmation studies were performed: one in dogs, the other in cats. After a period of acclimatisation, both the dogs and cats were orally infected with Echinococcus multilocularis protoscoleces. In the dog study, 10 dogs received a single dose of Milpro® tablets at a minimum dose of 0.5 mg/kg milbemycin oxime and 5 mg/kg praziquantel 18 days post-infection and 10 dogs received no treatment. In the cat study, 10 cats received a single dose of Milpro® tablets at a minimum dose of 2 mg/kg milbemycin oxime and 5 mg/kg praziquantel 7 days post-infection, 10 cats received a single dose of the treatment 18 days post-infection and 10 cats remained untreated. In both studies, intestinal worm counts were performed 23 days post-infection at necropsy. No worms were retrieved from any of the 30 treated animals. Nine of 10 control dogs had multiple worms (geometric mean 91, arithmetic mean 304) and all 10 control cats had multiple worms (geometric mean 216, arithmetic mean 481). The difference in worm counts between all three treated groups and their controls was highly significant (ANOVA p values of log transformed data <0.0001). Efficacy of 100 % was demonstrated for the elimination of adult E. multilocularis in dogs and cats as well as for elimination of immature E. multilocularis in cats as evidenced by the effectiveness of treatment 7 days post-infection. The treatments were well accepted and tolerated, and there were no adverse drug reactions observed.

Efficacy of a fixed combination of permethrin 54.5% and fipronil 6.1% (Effitix) in dogs experimentally infested with Ixodes ricinus.

BACKGROUND: Ticks are the most important vectors of disease-causing pathogens in domestic animals and are considered to be second worldwide to mosquitoes as vectors of human diseases. In Europe, Ixodes ricinus, the sheep tick, plays an important role as companion animal parasite but is also the primary vector of medically important diseases such as tick-borne encephalitis and Lyme borreliosis. The present study was designed to evaluate the efficacy under laboratory conditions of a new fixed spot-on combination of fipronil and permethrin (Effitix, Virbac) in treating and preventing tick infestations of Ixodes ricinus in dogs. METHODS: Twelve dogs were included in this randomized, controlled, blinded laboratory study. They were randomly allocated to two groups of six dogs each according to their pre-treatment live attached Ixodes ricinus tick count. On day 0, the dogs from Group 2 were treated with the recommended dose of Effitix, the dogs from Group 1 remained untreated. On days -2, 7, 14, 21, 28 and 35, all dogs were infested with 50 (±4) viable unfed adult Ixodes ricinus (20 ± 2 males, 30 ± 2 females). Ticks were removed and counted at 48 ± 2 hours post product administration or tick infestations. RESULTS: Through the study, the tick attachment rates for the untreated group were greater than 25% demonstrating that adequate levels of infestation were reached on the control dogs. Based on both arithmetic and geometric means (AM and GM), Effitix was deemed to be effective against Ixodes ricinus on days 2, 9, 16, 23, 30 and 37 with a percentage of efficacy of 98%, 100%, 100%, 100%, 93% and 95% respectively (AM). No clinical abnormalities were detected during the study. CONCLUSIONS: The study has shown under laboratory conditions, that Effitix is a safe and an effective combination to treat and protect dogs from Ixodes ricinus up to 37 days after administration. The high immediate efficacy of 98% evaluated at 48 hours post-treatment was particularly interesting, meaning that Effitix has a curative effect against ticks (Ixodes ricinus) and provides a rapid control of existing Ixodes ricinus infestation on a dog at the time of treatment.

Efficacy of fipronil combined with permethrin commercial spot on (Effitix) preventing Culex pipiens from feeding on dogs.

A controlled clinical trial was carried out to assess the adulticidal and anti-feeding effectiveness of a spot-on combining fipronil and permethrin (Effitix, Virbac, Carros, France) in preventing Culex pipiens from feeding on dogs. Twelve dogs with equal sensitivity to mosquitoes were included in the study and divided into two groups of six dogs: an untreated control group and a group treated with Effitix. All dogs were challenged with 80 females C. pipiens for 90 ± 5 min on days -7, 1, 7, 14, 21, and 28 (day 0 being treatment day). The number of engorged, dead, and live mosquitoes was determined after each exposure to treated and untreated dogs. Dead mosquitoes were also counted 24 h after exposure. The anti-feeding effect of the spot-on formulation was 100, 99.5, 97.7, 98.3, and 96.7% on days 1, 7, 14, 21, and 28, respectively. The mortality effect was 66.6, 55.9, 38, 17.2, and 12.3% on days 1, 7, 14, 21, and 28, respectively. At each challenge point, the mortality and anti-feeding effects on mosquitoes were significantly different between the control and treated group (p < 0.05). The results indicate that a combination of permethrin and fipronil could be used as an effective mosquito control strategy in dogs and is therefore recommended for use in a dirofilariasis prevention program.

Prevention of Babesia canis in dogs: efficacy of a fixed combination of permethrin and fipronil (Effitix®) using an experimental transmission blocking model with infected Dermacentor reticulatus ticks.

BACKGROUND: Two experimental studies using a transmission blocking model with Dermacentor reticulatus ticks infected with Babesia canis were performed to test the ability of Effitix® to prevent the transmission of babesiosis in dogs. METHODS: Four groups of seven dogs (experiment 1) and one group of eight dogs (experiment 2) were treated topically with a novel combination of fipronil and permethrin in a spot-on formulation (Effitix®, Virbac) respectively 28, 21, 14 and 7 days (experiment 1) and 2 days (experiment 2) prior to tick infestation. In each study, a control group of seven dogs (experiment 1) and eight dogs (experiment 2) remained untreated. On day 0, all dogs were infested with adult D.reticulatus ticks harboring B. canis. An efficacy failure (successfully infected) was regarded as a dog in the treated groups that was tested serologically positive for B.canis antibodies, using an indirect fluorescent antibody (IFA) assay and tested positive for B.canis by DNA-assay using PCR analysis. RESULTS: B.canis was transmitted by D.reticulatus to all untreated dogs (experiment 1) and six untreated dogs out of eight (experiment 2) as confirmed by IFA and PCR assays. The large majority of treated dogs (92.9% in experiment 1 and 100% in experiment 2) remained sero-negative over the challenge period. CONCLUSIONS: The treatment of dogs with Effitix® applied 2 to 28 days prior to infestation with D. reticulatus harboring B.canis, successfully prevented the transmission of canine babesiosis.

Assay of two 10% (w/v) fipronil spot-on formulations against feline infestations with Ctenocephalides felis.

A new fipronil-based spot-on formulation was evaluated against experimental flea infestations in cats in two studies. In both studies, eight cats served as negative controls (groups 1 and 4); on day 0, eight cats were treated with a 10% w/v fipronil-based spot-on solution (Effipro Spot-on, 0.5ml per cat, groups 2 and 5) and eight cats served as positive controls (Frontline Spot-on, 0.5ml per cat, groups 3 and 6). Each cat was infested on day - 1 with 50 fleas (study 1) and weekly (day 7-day 56) with 100 fleas (study 2). Geometric mean flea counts obtained 48h after the treatment or each re-infestation were reduced by 99.0 and 98.3% in groups 2 and 3, respectively, on day 2, compared to the negative control group. Cats were protected from re-infestations with an efficacy >99% for 58 days in group 5 and for 37 days in group 6.

Comparative efficacy of two fipronil spot-on formulations against experimental tick infestations (Ixodes ricinus) in dogs.

A parallel-group-design, randomized, unicentre and blinded controlled study was undertaken to assess the efficacy of a new fipronil-based spot-on formulation applied once to dogs against experimental Ixodes ricinus infestations. Six dogs served as negative controls (group 1), six dogs served as positive controls (group 2) receiving the original fipronil spot-on (Frontline(R) spot-on Dog, Merial) at a dosage of 0.67 mL for a dog weighing from 2 to 10 kg and 1.34 mL for a dog weighing from 10.1 to 20 kg and six dogs were treated with a 10% w/v fipronil-based spot-on solution (Effipro(R) Spot-on, Virbac SA) at an identical dosage (group 3, 0.67 mL for a dog weighing from 2 to 10 kg and 1.34 mL for a dog weighing from 10.1 to 20 kg). Each dog was sedated and subsequently infested with 50 unfed adult I. ricinus on days -7, -2, 7, 14, 21, 28 and 35. Forty-eight hours after the treatment and 48 h after each challenge (days -5, 2, 9, 16, 23, 30 and 37), the population of the remaining ticks was assessed for each animal. Geometric mean tick counts obtained were reduced by 99% and 94% on day 2 in groups 2 and 3, respectively, compared to the negative control group. Dogs were protected from re-infestations with an efficacy of >90% for 3 weeks in group 2 and for 5 weeks in group 3. Both 10% w/v fipronil-based spot-on solutions, despite different vehicles, were equally able to eradicate tick infestation, to prevent new infestations and were equally well tolerated.

Anthelmintic efficacies of a tablet formula of ivermectin-praziquantel on horses experimentally infected with three Strongylus species.

In this blinded randomized and controlled study, the anthelmintic efficacy of a tablet formula of ivermectin-praziquantel was evaluated in horses experimentally infected with three species of Strongylus larvae. Eighteen previously dewormed horses were inoculated on study day 0 with third-stage larvae of Strongylus vulgaris, Strongylus equinus, and Strongylus edentatus. The horses were randomly allocated to three groups (n = 6): test-drug (tablet formula), positive-control (reference gel), and negative-control (placebo tablet). On day 56, the horses were treated once with the respective drugs. On day 95, the horses were sacrificed, and necropsy examinations were performed to assess the status of the parasite burden (L4 and immature L5) and pathological lesions on selected organs and tissues. By the criteria of worm counts, the test-drug and positive-control showed, respectively, 100% and 97.3% anthelmintic efficacies on S. vulgaris, 100% and 81.4% on S. equinus, and equally 100% on S. edentatus. However, the efficacies on S. equinus and S. edentatus should be taken only as face values considering their respective low worm counts in the placebo group. The S. vulgaris-induced arterial lesions were also reduced in the test-drug and positive-control groups with efficacies of 73.9% and 62.9%, respectively. No adverse reactions were observed with either of the drugs. Our data demonstrate that the Equimax tablet formula was as safe and efficacious as the gel formula anthelmintic on large strongyles in horses.

Tracking individual proteins in living cells using single quantum dot imaging.

Single quantum dot imaging is a powerful approach to probe the complex dynamics of individual biomolecules in living systems. Due to their remarkable photophysical properties and relatively small size, quantum dots can be used as ultrasensitive detection probes. They make possible the study of biological processes, both in the membrane or in the cytoplasm, at a truly molecular scale and with high spatial and temporal resolutions. This chapter presents methods used for tracking single biomolecules coupled to quantum dots in living cells from labeling procedures to the analysis of the quantum dot motion.

Single quantum dot tracking based on perceptual grouping using minimal paths in a spatiotemporal volume.

Semiconductor quantum dots (QDs) are new fluorescent probes with great promise for ultrasensitive biological imaging. When detected at the single-molecule level, QD-tagged molecules can be observed and tracked in the membrane of live cells over unprecedented durations. The motion of these individual molecules, recorded in sequences of fluorescence images, can reveal aspects of the dynamics of cellular processes that remain hidden in conventional ensemble imaging. Due to QD complex optical properties, such as fluorescence intermittency, the quantitative analysis of these sequences is, however, challenging and requires advanced algorithms. We present here a novel approach, which, instead of a frame by frame analysis, is based on perceptual grouping in a spatiotemporal volume. By applying a detection process based on an image fluorescence model, we first obtain an unstructured set of points. Individual molecular trajectories are then considered as minimal paths in a Riemannian metric derived from the fluorescence image stack. These paths are computed with a variant of the fast marching method and few parameters are required. We demonstrate the ability of our algorithm to track intermittent objects both in sequences of synthetic data and in experimental measurements obtained with individual QD-tagged receptors in the membrane of live neurons. While developed for tracking QDs, this method can, however, be used with any fluorescent probes.

Detection of single DNA molecules by multicolor quantum-dot end-labeling.

Observation of DNA-protein interactions by single molecule fluorescence microscopy is usually performed by using fluorescent DNA binding agents. However, such dyes have been shown to induce cleavage of the DNA molecule and perturb its interactions with proteins. A new method for the detection of surface-attached DNA molecules by fluorescence microscopy is introduced in this paper. Biotin- and/or digoxigenin-modified DNA fragments are covalently linked at both extremities of a DNA molecule via sequence-specific hybridization and ligation. After the modified DNA molecules have been stretched on a glass surface, their ends are visualized by multicolor fluorescence microscopy using conjugated quantum dots (QD). We demonstrate that under carefully selected conditions, the position and orientation of individual DNA molecules can be inferred with good efficiency from the QD fluorescence signals alone. This is achieved by selecting QD pairs that have the distance and direction expected for the combed DNA molecules. Direct observation of single DNA molecules in the absence of DNA staining agent opens new possibilities in the fundamental study of DNA-protein interactions. This work also documents new possibilities regarding the use of QD for nucleic acid detection and analysis.