The effect of water and shampooing on the efficacy of a pyriprole 12.5% topical solution against brown dog tick (Rhipicephalus sanguineus) and cat flea (Ctenocephalides felis) infestations on dogs.

The efficacy of a single treatment with a 12.5% pyriprole spot-on formulation against induced infestations with R. sanguineus ticks and cat fleas (C. felis) as well as its persistence after repeated washing and shampooing was investigated in four separate studies. In a first study on R. sanguineus involving 32 beagle dogs, the efficacy at various time-points during the 30 days that followed treatment assessed 48 h after re-infestation ranged from 100% to 99.3%. No engorged ticks, alive or dead, were found in the treated animals. Shampooing 2 days after treatment and weekly washings did not affect the efficacy. In a second study on R. sanguineus involving 32 beagle dogs, the efficacy at various time-points during the 30 days that followed treatment assessed 48 h after re-infestation ranged from 100% to 96.8%. Single washing 8h after treatment and single shampooing 24 h after treatment had no negative impact on the efficacy of the product. In a third study on C. felis involving 28 beagle dogs, the efficacy at various time-points during the 30 days that followed treatment assessed 48 h after re-infestation was always 100% and weekly washings did not diminish the efficacy. In a last study on C. felis involving 24 beagle dogs, the efficacy at various time-points during the 5 weeks that followed treatment assessed 48 h after re-infestation ranged from 100% to 99.8%, and shampooing 24 h after treatment did not reduce the efficacy. The product was well tolerated by the dogs.

Efficacy of a single application of a 12.5% pyriprole topical solution against laboratory infestations with ticks (Ixodes ricinus, Dermacentor reticulatus, and Rhipicephalus sanguineus) on dogs.

In three separate studies, the efficacy of a single treatment with a 12.5% pyriprole spot-on solution was investigated against induced infestation with Ixodes ricinus, Dermacentor reticulatus and Rhipicephalus sanguineus on dogs (both sexes; Beagles in Studies 1 and 2, mixed-breed in Study 3). For each tick species, one group of 8 dogs left untreated (Studies 1 and 2) or treated with a placebo solution (Study 3) was compared with another group treated once with the spot-on solution at a dose rate of at least 12.5mg/kg. The dogs were infested with 50 unfed adult ticks of the respective species at various time-points before and after treatment and the surviving attached and unattached ticks were recorded 48 h after re-infestation. For each tick species, efficacy was assessed for each time-point and cumulatively for the whole evaluation period. The dogs were submitted to general health observations and clinical assessments during the study. Efficacy against I. ricinus and R. sanguineus was 100% during the whole evaluation period of 30 days. For D. reticulatus cumulative efficacy for the 30 days after treatment was 98.9%. The product was well tolerated by all the animals.

Canine leishmaniosis in Cyprus due to Leishmania infantum MON 1.

During a serological survey in 1996, a total of 601 dogs (group I) distributed all over the government controlled southern area of Cyprus was examined using an enzyme-linked immunosorbent assay (ELISA) for the presence of specific antibodies directed against soluble antigens of promastigote stages of Leishmania infantum. The overall seroprevalence rate in this group was 1.7%. A second group (group II) of dogs was selected from regions where seropositive dogs where determined within the first group. In group II specific anti-Leishmania antibodies could be detected in 30 of 301 dogs investigated (10%). The highest seroprevalence rates were found in the regions of Agios Georgios (26.2%) and Limnatis (12.2%). Ten parasite isolates from ten dogs (six with typical symptoms of canine leishmaniosis and four without symptoms) originating from five locations could be characterised by zymodeme analysis. All ten isolates were identified as L. infantum zymodeme MON 1.

Comparative speed of kill between nitenpyram, fipronil, imidacloprid, selamectin and cythioate against adult Ctenocephalides felis (Bouché) on cats and dogs.

Speed of kill and percentage kill of nitenpyram (CAPSTAR) was compared to fipronil (Frontline) spot-on), imidacloprid (Bayvantage/Advantage), selamectin (Stronghold/Revolution) and cythioate (Cyflee) against adult fleas on cats and dogs 3 and 8h post-treatment. Selamectin was used on dogs only; cythioate was used on cats only. Groups of eight cats and eight dogs (four males and four females each) were experimentally infested with 100 unfed fleas 1 day prior to treatment with the test products. One group of cats and one group of dogs served as control. Fleas were collected from four cats and four dogs in each group (two males and two females) by combing 3h after treatment, the remaining four cats or dogs were combed 8h after treatment. In cats cythioate treatment resulted in a mean efficacy of 62.4 and 97.4% at 3 and 8h post-treatment, respectively. Imidacloprid efficacy at the same times was 26.9 and 82.8%, whereas fipronil efficacy was 24.3 and 62.6% efficacy, respectively. In dogs mean efficacy 3 and 8h after treatment with selamectin was 39.7 and 74.4%; with imidacloprid efficacy was 22.2 and 95.7%, respectively and 35.9 and 46.5%, respectively after treatment with fipronil. Nitenpyram was 100% effective in cats and 99.1% effective in dogs within 3h of treatment and 100% effective in cats and dogs within 8h.

Clinical, serologic, and parasitologic follow-up after long-term allopurinol therapy of dogs naturally infected with Leishmania infantum.

Canine leishmaniasis usually is treated with antimony compounds, but frequent relapses, adverse effects, high costs, and development of resistance to long-term antimonial therapy emphasize the importance of searching for alternative antileishmanial drugs. Allopurinol was used at a dosage of 10 mg/kg/day PO to treat 10 dogs naturally infected with Leishmania infantum for a period of 2-24 months. Nine dogs recovered within 2-6 months of chemotherapy, and no relapses were observed during the treatment of up to 20 months. However, 3 of 4 dogs relapsed after treatment was discontinued. These dogs again recovered clinically when therapy was resumed. Parasite-specific immunoglobulin concentrations (IgG2) were high in all dogs before therapy and remained high even in clinically cured dogs during or after therapy. On the other hand, specific IgG1 reactions, which have been shown to be detectable in symptomatic animals, persisted in 7 dogs for long periods after clinical recovery. Three of these dogs relapsed within 2-4 weeks after interrupting therapy. However, 1 dog with no detectable specific IgG1 reaction at the end of therapy did not relapse in the following 4 months. Parasites could be detected in 8 of 9 dogs after clinical improvement by in vitro cultivation or polymerase chain reaction (PCR) testing of lymph node aspirates. In 4 of these dogs, parasites also were detected in blood samples by PCR. Hence, these clinically cured dogs must be regarded as reservoirs of Leishmania and allopurinol cannot be recommended in endemic areas.

Efficacies of albendazole sulfoxide and albendazole sulfone against In vitro-cultivated Echinococcus multilocularis metacestodes.

The metacestode stage of Echinococcus multilocularis is the causative agent of alveolar echinococcosis (AE), a parasitic disease affecting the liver, with occasional metastasis into other organs. Benzimidazole carbamate derivatives such as mebendazole and albendazole are currently used for chemotherapeutic treatment of AE. Albendazole is poorly resorbed and is metabolically converted to its main metabolite albendazole sulfoxide, which is believed to be the active component, and further to albendazole sulfone. Chemotherapy with albendazole has been shown to have a parasitostatic rather than a parasitocidal effect; it is not effective in all cases, and the recurrence rate is rather high once chemotherapy is stopped. Thus, development of new means of chemotherapy of AE is needed. This could include modifications of benzimidazoles and elucidiation of the respective biological pathways. In this study we performed in vitro drug treatment of E. multilocularis metacestodes with albendazole sulfoxide and albendazole sulfone. High-performance liquid chromatography analysis of vesicle fluids showed that the drugs were taken up rapidly by the parasite. Transmission electron microscopic investigation of parasite tissues and nuclear magnetic resonance spectroscopy of vesicle fluids demonstrated that albendazole sulfoxide and albendazole sulfone had similar effects with respect to parasite ultrastructure and changes in metabolites in vesicle fluids. This study shows that the in vitro cultivation model presented here provides an ideal first-round test system for screening of antiparasite drugs.