Preventive efficacy of four or six monthly oral doses of 24 µg/kg moxidectin compared to six monthly doses of Heartgard® Plus or Interceptor® Plus against macrocyclic lactone-resistant heartworm (Dirofilaria immitis) strains in dogs.

BACKGROUND: Recent reports indicated that increasing the monthly oral dosage and the number of consecutive monthly doses of moxidectin improved the efficacy against macrocyclic lactone (ML)-resistant Dirofilaria immitis. The two laboratory studies reported here evaluated the efficacy of four or six monthly oral doses of 24 µg/kg moxidectin compared to six monthly doses of either Heartgard® Plus (ivermectin/pyrantel) or Interceptor® Plus (milbemycin oxime/praziquantel) against ML-resistant D. immitis strains. METHODS: Dogs were inoculated 30 days prior to first treatment with 50 third-stage (L3) larvae of a ML-resistant strain of D. immitis, ZoeLA or JYD-34. In each study, dogs (six per group) were randomized to treatment with six monthly doses of placebo, four or six monthly doses of 24 µg/kg moxidectin, or six monthly doses of Heartgard® Plus or Interceptor® Plus at their label dose rates. Efficacy was evaluated by adult heartworm counts approximately nine months after L3 inoculation. RESULTS: All negative-control dogs were infected with adult heartworms (geometric mean, 35.6; range, 24-41) for ZoeLA and (geometric mean, 32.9; range, 30-37) for JYD-34. Efficacies against ZoeLA for moxidectin, Heartgard® Plus and Interceptor® Plus were ≥ 96.1%, 18.7% and 21.2%, respectively. Adult counts for both moxidectin-treated groups were significantly lower than negative control (P < 0.0001), significantly lower than Heartgard® Plus and Interceptor® Plus (P < 0.0001), but not significantly different from each other (P = 0.5876). Counts for Heartgard® Plus and Interceptor® Plus were not significantly different than negative control (P ≥ 0.2471). Efficacies against JYD-34 were ≥ 95.9%, 63.9% and 54.6% for moxidectin, Heartgard® Plus and Interceptor® Plus, respectively. Counts for all groups were significantly lower than negative control (P ≤ 0.0001). Counts for six monthly doses of moxidectin were significantly lower than those for four monthly doses (P = 0.0470), and the counts for both moxidectin-treated groups were significantly lower than Heartgard® Plus and Interceptor® Plus (P ≤ 0.0002). CONCLUSIONS: Moxidectin administered orally at 24 µg/kg to dogs for four or six consecutive months was ≥ 95.9% effective in preventing the development of two ML-resistant heartworm strains and resulted in significantly fewer adult D. immitis than in dogs treated with Heartgard® Plus or Interceptor® Plus when administered for six consecutive months at their approved label dosages in two laboratory efficacy studies.

Efficacy evaluation of anthelmintic products against an infection with the canine hookworm (Ancylostoma caninum) isolate Worthy 4.1F3P in dogs.

Ancylostoma caninum is the most prevalent intestinal nematode of dogs, and has a zoonotic potential. Multiple-drug resistance (MDR) has been confirmed in a number of A. caninum isolates, including isolate Worthy 4.1F3P, against all anthelmintic drug classes approved for hookworm treatment in dogs in the United States (US). The cyclooctadepsipeptide emodepside is not registered to use in dogs in the US, but in a number of other countries/regions. The objective of this study was to evaluate the efficacy of emodepside + praziquantel, as well as three commercial products that are commonly used in the US for treatment of hookworms, against a suspected (subsequently confirmed) MDR A. caninum isolate Worthy 4.1F3P. 40 dogs infected on study day (SD) 0 with 300 third-stage larvae, were randomly allocated to one of five treatment groups with eight dogs each: pyrantel pamoate (Nemex®-2), fenbendazole (Panacur® C), milbemycin oxime (Interceptor®), emodepside + praziquantel tablets and non-treated control. Fecal egg counts (FEC) were performed on SDs 19, 20, 22, 27, 31 and 34. All treatments were administered as per label requirements on SD 24 to dogs in Groups 1 through 4. Two additional treatments were administered on SDs 25 and 26 to dogs in Group 2 as per label requirements. Dogs were necropsied on SD 34 and the digestive tract was removed/processed for worm recovery and enumeration. The geometric mean (GM) worm counts for the control group was 97.4, and for the pyrantel pamoate, fenbendazole, milbemycin oxime, and emodepside + praziquantel groups were 74.8, 72.0, 88.9, and 0.4, respectively. These yielded efficacies of 23.2%, 26.1%, and 8.8%, and 99.6%, respectively. These data support previous findings of the MDR status of Worthy 4.1F3P as treatments with pyrantel pamoate, fenbendazole and milbemycin oxime lacked efficacy. In sharp contrast, Worthy 4.1F3P was highly susceptible to treatment with emodepside + praziquantel.

Praziquantel Resistance in the Zoonotic Cestode Dipylidium caninum.

Dipylidium caninum is a cosmopolitan cestode infecting dogs, cats, and humans. Praziquantel is a highly effective cestocidal drug and resistance in adult cestodes has not been reported. From 2016 to 2018, a population of dogs with cestode infections that could not be eliminated despite multiple treatments with praziquantel or epsiprantel was identified. Cases of D. caninum were clinically resistant to praziquantel and could not be resolved despite increasing the dose, frequency, and duration of treatment. Resistant isolates were identified and characterized by sequencing the 28S, 12S, and voltage-gated calcium channel beta subunit genes. Cases were only resolved following treatment with nitroscanate or a compounded pyrantel/praziquantel/oxantel product. Clinicians should be aware of this alarming development as treatment options for cestodes are limited in both human and veterinary medicine.

Comparative efficacy of a spot-on formulation containing emodepside and praziquantel (Profender ®, Bayer) and praziquantel and pyrantel oral tablets (Drontal ® for Cats) against experimental Ancylostoma ceylanicum infections in cats.

Ancylostoma ceylanicum is a common zoonotic hookworm of dogs and cats throughout Asia and has also been reported to occur within the Australasian region. The aim of this study to was to determine the efficacy of a spot-on formulation containing emodepside and praziquantel (Profender(®), Bayer) and praziquantel and pyrantel oral tablets (Drontal(®) for Cats, Bayer) against experimental A. ceylanicum infections in cats. Twenty-four kittens were each subcutaneously injected with 100 infective third-stage larvae of A. ceylanicum. Kittens were stratified by egg count and randomly allocated equally into control and two treatment groups. The first group were treated with emodepside 2.1%/praziquantel 8.6% (Profender®, Bayer) at the recommended label dose. The second group was treated with 80 mg pyrantel and 20mg praziquantel (Drontal(®) for Cats, Bayer) at the recommended label dose. The kittens in the control group were not treated. Egg counts were performed daily until the end of the study period and compared for the treated and control groups. No eggs were detected in the treated group of kittens within 4 days of treatment and faecal samples from this group remained negative throughout the rest of the study, resulting in a treatment efficacy (egg reduction) of 100% (P<0.0001). The egg counts remained high (993 ± 666 epg) in the untreated control group for the rest of the study period. This study demonstrated that both combination products containing topical emodepside/praziquantel (Profender(®), Bayer) and praziquantel/pyrantel oral tablets (Drontal(®) for Cats, Bayer) given at the recommended dose is highly effective against infection with A. ceylanicum in cats.

Feline intestinal parasites in Finland: prevalence, risk factors and anthelmintic treatment practices.

The aim of this study was to estimate the prevalence of feline intestinal parasites in Finland and to determine the possible risk factors for infection. Altogether 411 feline fecal samples were analyzed with a flotation method to reveal helminth eggs and protozoan oocysts. Of the samples, 402 were also screened for Giardia species antigens with a commercial enzyme-linked immunosorbent assay kit. The cat owners completed a questionnaire. Toxocara cati prevalence was 5.4% and Toxascaris leonina 0.2%. Taenia species eggs were found in 1.5% of the samples and Isospora felis in 0.7%, whilst 3.2% of the samples tested positive for Giardia species antigen. Risk factors for Toxocara/Toxascaris species infection included being a non-pedigree cat, having access to the outdoors, living outside of the cities and receiving home-made food. Pedigree cats were at greater risk of contracting Giardia duodenalis. The majority of the cat owners (62.4%) treated their cat with anthelmintics 2-4 times per year.

Efficacy, safety and palatability of a new broad-spectrum anthelmintic formulation in dogs.

The efficacy, safety and palatability of a new flavoured chewable anthelmintic tablet were investigated in dogs. The efficacy, based on worm counts, of a single recommended therapeutic dose (RTD) of 5 mg pyrantel + 20 mg oxantel + 5 mg praziquantel/kg bodyweight was assessed in experimental infections (EI) and natural infections (NI) with Trichuris vulpis, Echinococcus granulosus and Toxocara canis. For T vulpis, the efficacy of the treatment was 99.3 per cent in EI (comparing groups of six treated and six control dogs) and 100 per cent in NI (nine treated and nine control dogs). For E granulosus, the efficacy was more than 99.9 per cent in EI (11 treated and 11 control dogs). For T canis, the efficacy was 94.3 per cent in EI (10 treated and 10 control dogs) and 100 per cent in NI (12 treated and 13 control dogs). In a field study, Ancylostoma caninum (11 dogs) and T canis (11 dogs) faecal egg counts were reduced by more than 99 per cent, and in eight dogs with Dipylidium caninum proglotides in the faeces the efficacy was 100 per cent. The tablets were readily consumed by 56 of 64 (87.5 per cent) privately owned dogs. Safety was assessed in groups of six dogs treated either once with twice the RTD, once with six times the RTD, with twice the RTD on three consecutive days, or untreated. There were no significant differences in blood parameters between the groups, and no abnormal clinical findings. Two dogs treated with six times the RTD vomited, but no vomiting was observed when administration was repeated two days later.

Efficacy of a combination product containing pyrantel, febantel and praziquantel (Drontal Plus Flavour, Bayer Animal Health) against experimental infection with the hookworm Ancylostoma ceylanicum in dogs.

Ancylostoma ceylanicum is a common hookworm of dogs, cats and humans in Asia. More recently, this hookworm was found to infect dogs in Australia. The objective of this study was to determine the efficacy of a combination product containing pyrantel, febantel and praziquantel (Drontal) Plus Flavour, Bayer) against A. ceylanicum in experimentally infected dogs. Twelve dogs were each subcutaneously injected with 300 infective third-stage larvae of A. ceylanicum. Pups were stratified by egg count and randomly allocated equally into control and treatment groups. The pups in the treatment group were treated orally at 20 days post-infection with a tablet containing pyrantel, febantel and praziquantel (Drontal Plus Flavour, Bayer) with the recommended dose of one tablet per 10 kg bodyweight. The dogs in the control group were not treated. Egg counts were performed daily until the end of the study period and compared for the treated and control groups. No eggs were detected in the treated group of pups within 3 days of treatment, and faecal samples from this group remained negative throughout the rest of the study resulting in a treatment efficacy (egg reduction) of 100% (p = 0.0011). The egg counts for the untreated group remained high for the rest of the study period. This trial demonstrated that a combination tablet containing pyrantel, febantel and praziquantel (Drontal Plus Flavour, Bayer) given at the manufacturer's recommended dose is effective against infection with A. ceylanicum in dogs.

Ascaris lumbricoides: a travel joke?

Intestinal nematodes affect more than a billion people worldwide. They are commonly found in regions with poor fecal sanitation, such as developing countries. Although most of the nematode infections are non-fatal diseases, they contribute to significant morbidities such as loss of work capacity and malnutrition. We are presenting an 80-year-old male who was diagnosed with Ascaris Lumbricoides after a return from recent travel to Greece, with some clinical endoscopic images.

Survey of intestinal parasites in stray dogs in the Madrid area and comparison of the efficacy of three anthelmintics in naturally infected dogs.

Using routine coprological methods, 1161 faecal samples from animal shelters located in Madrid (Spain) were analysed, showing a 28% prevalence for different intestinal parasites: Giardia duodenalis (7%), Cystoisopora spp. (3.8%), Toxocara canis (7.8%), Toxascaris leonina (6.3%), Ancylostomidae (4%), Trichuris vulpis (3.3%), Taenidae (2.9%) and Dipylidium caninum (0.9%). The therapeutic efficacies of mebendazole at a dose of 22 mg/kg once daily for 3 days, fenbendazole at a dose of 50 mg/kg once daily for 3 days and a drug combination of febantel-pyrantel-praziquantel at a dose of 15-5-5 mg/kg once were valuated and compared by collecting faecal samples on days 9 and 16 post-treatment from naturally infected dogs in field-trial conditions. From the infected dogs (321 dogs), 150 animals were selected for the study. Distribution randomly divided the animals into three study groups of ten dogs per parasite and per treatment group: group A, mebendazole; group B, fenbendazole and group C, febantel-pyrantel-praziquantel. The therapeutic efficacy against ascarids and ancylostomids (days 9-16) was very high (75-100%) for the three groups: for T. canis, 100% in group A, 80-100% in group B, 97-100% in group C; for T. leonina, 98-100% in group A, 100% in group B, 92-94% in group C and for ancylostomids, 100% in group A, 99-100% in group B, 90-100% in group C. On the other hand, the highest efficacy against Taenidae infections was in group B (90-100%), followed by groups C (73-91%) and A (70-90%).

Field evaluation of the efficacy and the safety of a combination of oxantel/pyrantel/praziquantel in the treatment of naturally acquired gastrointestinal nematode and/or cestode infestations in dogs in Europe.

In five multicentre field trials, the efficacy and safety of a combination of oxantel/pyrantel/praziquantel (Dolpac), Vetoquinol SA) in the treatment of naturally acquired gastrointestinal nematode and/or cestode infestation in dogs was evaluated in northern and southern Europe. Forty-eight investigators from France, Belgium, Germany, Italy and Spain enrolled 329 dogs to be treated with the tested combination; 235 of these dogs complied with the inclusion criteria of the protocol and had a tested helminth identified on Day 0. A pooled analysis was performed on each of the following helminth species: Toxocara canis, Ancylostoma caninum, Toxascaris leonina, Trichuris vulpis, Uncinaria stenocephala, Taenia spp. and Dipylidium caninum, which were isolated on Day 0. The main efficacy criterion was the egg per gram (epg) percent reduction of the nematodes and the absence of proglottids and or eggs for the cestodes. After treatment, dogs were examined on Day 7, Day 14 and Day 21. The efficacy of the combination against Toxocara canis was 99.1%, 98.8% and 98.9% on Day 7, Day 14 and Day 21, respectively. At the same occasions the efficacy was, respectively, 99.2%, 99.2% and 99.3% against Ancylostoma caninum, 97.3%, 97.2% and 98.4% against Trichuris vulpis, 98.4%, 98.8% and 98.8% against Uncinaria stenocephala, 98.9%, 99.5% and 99.9% against Toxascaris leonina, 97.1%, 100% and 100% against Dipylidium caninum and 100% against Taenia spp.

Comparative efficacy of flubendazole chewable tablets and a tablet combination of febantel, pyrantel embonate and praziquantel against Trichuris vulpis in experimentally infected dogs.

Fourteen of 23 dogs developing patent Trichuris vulpis infections by 120 days p.i. with 5000 embryonated eggs were allocated into three groups. One group was treated with flubendazole 220 mg chewable tablets (Flubenol) at the recommended dose regimen once daily for 3 days. The second group was given the recommended single treatment with a tablet containing 150 mg febantel, 144 mg pyrantel embonate and 50 mg praziquantel in combination (Drontal Plus). The third group remained untreated. All dogs were necropsied for worm counts 10 or 11 days after (first) treatment. No worms were recovered from the flubendazole treated dogs resulting in a significant worm count reduction of 100%. In contrast, 2 of 5 animals treated with the combination of febantel, pyrantel embonate and praziquantel remained infected; the geometric mean worm burden was reduced by 99.4% as compared to the control group but did not differ significantly from those of the controls.

Polyparasitism with Schistosoma mansoni, geohelminths, and intestinal protozoa in rural Côte d'Ivoire.

Single species infections with schistosomes, geohelminths, and intestinal protozoans are common over large parts of sub-Saharan Africa, and it is expected that polyparasitism affects a considerable proportion of the population, hence posing a great toll on public health. However, few investigations have been carried out to quantify the extent of polyparasitism. Here, a detailed assessment is reported for the epidemiology of Schistosoma mansoni, geohelminths, and intestinal protozoan infections, with particular emphasis on polyparasitism among 260 community members in rural Cjte d'Ivoire. Schistosoma mansoni, Entamoeba coli, and hookworm were the predominant species with prevalences of 71.5, 64.6, and 51.9%, respectively. Only 8 individuals displayed no infection, whereas two-thirds of the population harbored 3 or more parasites concurrently. There were a series of significant pairwise parasite co-occurrences, e.g., between S. mansoni and hookworms and between S. mansoni and E. coli. It is concluded that polyparasitism in the population studied here was very common, which is probably the case also in other areas of rural Cjte d'Ivoire and elsewhere in sub-Saharan Africa. These findings call for integrated approaches to effectively control multiple parasitic and protozoan infections.

Efficacy of a combination febantel-praziquantel-pyrantel product, with or without vaccination with a commercial Giardia vaccine, for treatment of dogs with naturally occurring giardiasis.

OBJECTIVE: To determine efficacy of treatment with a combination febantel-praziquantel-pyrantel product, with or without vaccination with a commercial Giardia vaccine, in dogs with naturally occurring giardiasis. DESIGN: Prospective trial. ANIMALS: 16 Beagles naturally infected with Giardia duodenalis. PROCEDURES: During phase 1, 6 dogs were treated with the parasiticide for 3 days (4 were also vaccinated). Four weeks later, all 6 dogs were treated with the parasiticide again for 5 days and were bathed and moved to clean cages after the last treatment (phase 2). Nine dogs were treated with the parasiticide for 3 (n = 4) or 5 (5) days and bathed and moved to clean cages after the last treatment (phase 3). Fecal samples were collected twice weekly for 24 days after treatment and tested for cysts with a quantitative zinc sulfate flotation technique and for Giardia antigen with an immunoassay. RESULTS: Dogs in phase 1 were all shedding cysts again by day 24. In phase 2, only 1 dog shed cysts after treatment, and shedding was transient (day 17). In phase 3, neither cysts nor antigen was detected in fecal samples from 2 of 4 dogs treated for 3 days and 4 of 5 dogs treated for 5 days. In 18 of 57 (31.6%) fecal samples, cysts were seen, but results of the immunoassay were negative. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that when a combination febantel-praziquantel-pyrantel product is used to treat dogs with giardiasis, bathing and changing the environment after treatment may be more important in preventing recurrence than duration of treatment.

Efficacy and safety of selamectin against gastrointestinal nematodes in cats presented as veterinary patients.

A series of randomized, controlled, masked, field (veterinary patient) studies were conducted in the USA and Europe to evaluate the efficacy of selamectin, a novel macrocyclic lactone of the avermectin subclass, in the treatment of naturally acquired gastrointestinal nematode infections in cats. After confirmation of ascarid and/or hookworm infection, 298 cats of various ages and breeds were randomly assigned to treatment with selamectin (n=202) or an existing commercially approved positive-control product (n=96). Unit doses of selamectin (providing a minimum dosage of 6mgkg(-1)) were administered topically to the skin in a single spot at monthly intervals. Quantitative fecal examinations were performed on days 0 (before treatment), 30, and 60. In the selamectin-treated cats, fecal ascarid egg counts were reduced by 99.6 to 100% on day 30, and by 99.9 to 100% on day 60. Fecal hookworm egg counts were reduced by 98.3% on day 30, and by 100% on day 60 in the selamectin-treated cats. The positive-control products achieved reductions in egg counts of 96.5 to 100% (ascarids) and 98.9 to 99.9% (hookworms). These studies have shown that monthly topical administration of selamectin is safe and highly effective in the treatment of naturally acquired ascarid and hookworm infections in cats.

Evaluation of albendazole, pyrantel, bephenium, pyrantel-praziquantel and pyrantel-bephenium for single-dose mass treatment of necatoriasis.

An effective drug for single-dose mass treatment of necatoriasis was sought by testing three drugs and two drug combinations in Ethiopian immigrants to Israel found to have light infections. The drugs tested sequentially in single-doses were pyrantel pamoate (20 mg kg-1, 81 subjects); bephenium hydroxynaphthoate (2.5-5 g, 65 subjects); combined pyrantel and bephenium (25 subjects); combined pyrantel (20 mg kg-1) and praziquantel (40 mg kg-1) (16 subjects); and albendazole (400 mg, 77 subjects). Follow-up under conditions without likelihood of reinfection was by one stool examination. Cure rates with albendazole, pyrantel-bephenium and pyrantel-praziquantel were 84, 80 and 81% respectively; these rates were significantly higher than the 49% found for bephenium and the 51% for pyrantel (P less than 0.05). Egg reductions in those not cured were pyrantel (22%), bephenium (6%), pyrantel-bephenium (34%), pyrantel-praziquantel (3%) and albendazole (6%). Albendazole was the most promising single drug treatment; unexpected was the high effectiveness of pyrantel-praziquantel in combination.

Dosis única antihelmíntica: estudio comparativo con dosis única, entre oxantel/pirantel y albendazol en ascariasis, tricocefalosis y uncinarias / Single antihelminthic dosage: comparative study with single doses between oxantel/pirantel and albendazole in ascariasis, trichocephaliasis and uncinarias

Se presentan los resultados de un estudio comparativo entre el oxantel-pirantel y el albendazol, en un grupo de 60 años parasitados por alguno de los siguientes helmintos transmitidos por el suelo: áscaris, tricocéfalos y uncinarias. Los medicamentos fueron administrados en dosis única: el oxantel-pirantel a razón de 20 miligramos-/kilogramo de peso, y el albendazol en dosis total de 400 milígramos. Se observaron excelentes resultados con ambos medicamentos en el tratamiento de la ascariasis. En la curación parasitológica de la uncinariasis el oxantel-pirantel exhibió superioridad (85.7%) de los casos tratados) sobre el albendazol (66.7% de los casos tratados); y, en lo que respecta a la reducción en el número de huevecillos, ambas drogas demostraron ser de utilidad. En las tricocefalosis de grados, I, II y III la curación obtenida con oxantel-pirantel fué superior. En relación a la disminución de huevecillos en las heces, existió una ligera superioridad por parte del oxantel-pirantel. En el grado IV de tricocefalosis, el efecto terapéutico de ambos medicamentos mostró muy poca utilidad cuando son suministrados en dosis única. Se propone una escala de los grados de parasitosis para ser utilizada en la evaluación de drogas antihelmínticas