A review of the off-label use of selamectin (Stronghold/Revolution) in dogs and cats

Continuous Flow Inter- and Intramolecular Macrolactonization under High Dilution Conditions

An efficient continuous flow process for the macrolactonization of seco acids and diacids using diols in the presence of Mukaiyama reagent (N-methyl-2-chloropyridinium iodide) has been developed for medium to large sized macrocyclic lactones. In comparison with other methods, the continuous flow process provided good to high yield in a short reaction time. By using this methodology, a wide range of macrocyclic lactones (11 compounds), dilactones (15 compounds), and tetralactone derivatives (2 compounds) with various ring sizes (12-26 atoms in the core) were synthesized in just 35 min of residence time. Advantageously, macrolactonization under the flow process is very elegant to handle the high dilution of reactants with a defined perfluoroalkoxy alkanes (PFA) tube reactor volume (7 mL).

Case Report: Notoedric Mange and Aelurostrongylidosis in Two Domestic Cats From Rural Environment in Romania

This article describes two cases of notoedric mange concurrent with aelurostrongylidosis in two domestic-owned cats from a rural environment in Romania. Two European shorthair cats originating from the same litter were referred to our clinic, at 2 months apart, with a history of skin lesions, pruritus, weight loss, and respiratory signs. Cats lived mainly outdoor together with the queen and a third littermate. The latter two expressed the same clinical signs and had died before the presentation of the first cat. None of the four cats was vaccinated, dewormed, or treated for external parasites. Coat brushing, skin scrapings, skin cytology, earwax direct microscopic examination, and coproparasitological techniques (flotation and Baermann methods) were used as laboratory procedures. A blood sample was also collected for hematology, blood biochemistry, and feline immunodeficiency virus/feline leukemia virus (FIV/FeLV) test. Notoedres cati mites in high numbers were identified by all complementary tests, alongside fleas and Aelurostrongylus abstrusus first-stage larvae. The blood analysis revealed neutrophilia, and the FIV/FeLV fast test was negative. The cats were successfully treated off-label with selamectin spot-on formulation (Stronghold^®, Zoetis) three times at 1- or 4-week intervals. Furthermore, they were treated with amoxicillin trihydrate/clavulanic acid, housed indoor, and fed with a commercial diet. Before presentation to the clinic, the female cat was unsuccessfully treated with a combination of fipronil, S-methoprene, eprinomectin, and praziquantel. During this period, the female cat remained outdoor and fed with home wastes. The cats become negative for A. abstrusus L1 larvae after 2–4 months of treatment. The owners developed pruritic skin lesions 1 month after introducing the first cat in the house. In conclusion, notoedric mange and aelurostrongylidosis can be treated successfully with selamectin as a spot-on formulation and the treatment must be continued until no parasite will be detected through specific techniques. The success of treatment depends on improving the quality of animal life (nutrition and hygiene) and treatment of secondary complications.

Streptomyces derivatives as an insecticide: Current perspectives, challenges and future research needs for mosquito control

The pervasiveness of arboviruses in wreaking havoc on public health has lingered on international health agendas. A scarcity of mosquito-borne disease vaccines and therapies demands prompt attention, as billions of people worldwide are at risk of infections. It is widely known that vector control continues, and in some diseases, remains the only resort in suppressing disease transmissions we presently possess at its disposal. But the use of commercial insecticides is being crippled by the widespread insecticide resistance, which greatly menaces their efficacies, toxicological repercussions such as environmental pollution and human health risk. Rather, an environmentally benign technique of employing Streptomyces isolates from settings such as terrestrial soils, marine sediments, and mangrove soils for Culicidae management has recently received a lot of positive attention. Streptomyces' capacities to produce a wide range of bioactive secondary metabolites that contribute to pharmaceutical, agricultural and veterinarian, Streptomyces-derived bioactive compounds are increasingly being considered for use in vector control. Herein, we compiled all of the available datasets on the effectiveness of Streptomyces-derived compounds against major mosquito vectors of medical importance. Aedes, Anopheles, and Culex are used to assess the toxicity of crude extracts or fractions. This paper reviewed the promising ovicidal, larvicidal, and pupacidal effects of different Streptomyces strains. Notably, no research into the adulticidal effect of Streptomyces-derived compounds has yet been done. Aside from the genetic makeup, the production of secondary metabolites from Streptomyces depends on the growing conditions. And that, to optimise the maximum yield of highly potent bioactive compounds being extracted, solvents' choice is of paramount importance. Thus, both cultivation parameters and the choice of organic solvents for secondary metabolites extraction will be discussed. Furthermore, biases derived from different studies have implied the need for standardizing experimental procedures. While entomological data should be collected consistently across all studies to expedite evidence-based policymaking of bioinsecticides, the quality of data from vector control interventions - particularly the experimental design, execution, analysis, and presentation of results of vector control studies - will be thoroughly reviewed. Lastly, to promote consistency and reliability, these knowledge gaps are identified, along with a discussion of current perspectives on vector control, global bioinsecticide trends, challenges on commercializing bioinsecticides and future research needs.

Safety and efficacy of a new spot-on formulation of selamectin plus sarolaner in the treatment and control of naturally occurring flea infestations in cats presented as veterinary patients in Australia

Background

The safety and efficacy of a new spot-on formulation of selamectin plus sarolaner were evaluated for the treatment and control of natural flea infestations on cats in two non-randomised, multi-centre clinical trials conducted in 8 different locations in Queensland, Australia.

Methods

One hundred and four cats from 65 different households were enrolled across the two studies. Demographic characteristics of cats in the two studies were similar. The new spot-on formulation of selamectin and sarolaner was administered topically once a month for 3 consecutive months at a minimum dosage of 6 mg/kg selamectin (dose range 6–12 mg/kg) plus 1 mg/kg sarolaner (dose range 1–2 mg/kg). Cats were dosed on Days 0 (pre-treatment), 30 and 60 and physical examinations and flea counts were conducted on Days 0, 30, 60 and 90. Efficacy assessments were based on the percentage reduction in live flea counts post-treatment compared to Day 0.

Results

In Study A, at enrolment, primary cats had flea counts ranging from 6 to 107 (arithmetic mean 21.0). The selamectin and sarolaner spot-on formulation resulted in arithmetic mean efficacy of 98.0%, 100% and 100% on Days 30, 60 and 90, respectively. In Study B, at enrolment, primary cats had flea counts ranging from 6 to 22 (arithmetic mean 10.0). The selamectin and sarolaner spot-on formulation resulted in arithmetic mean efficacy of 99.7%, 100% and 100% on Days 30, 60 and 90, respectively.

Conclusions

The new spot-on formulation of selamectin plus sarolaner topically administered at monthly intervals at the minimum dosage of 6.0 mg/kg selamectin and 1.0 mg/kg sarolaner was safe and highly effective against natural infestations of fleas under a range of geographical conditions, representative of both tropical and subtropical regions of Australia.

Treatment of Harvest Mite Infestation in Dogs Using a Permethrin 54.5% and Fipronil 6.1% (Effitix®) Topical Spot-On Formulation

Background—The study aims to assess the efficacy of a permethrin 54.5%-fipronil 6.1%-based spot-on solution in dogs naturally infested with Neotrombicula in an open-label controlled study. Methods—Ten naturally infested dogs received one drop per affected site on day (D) 0, and on D14, the rest of the pipette was applied on the skin between the shoulders. Five dogs served as sentinels. Parasite score (0–3), skin lesions (0–4), and investigator pruritus scale (0–4) were assessed on D0, D1, D14, and D28. Results—No treated dogs developed adverse reactions. Parasite score of sentinel dogs was maintained between 1.8 (D0, D1, and D28) and 2.2 (D14). In treated dogs, D0 parasite score was 2.4. It was significantly reduced from D1 (0.5; p < 0.002) to D28 (0.1; p < 0.002). The lesion score was 2.9 on D0 and D1; it was significantly reduced on D14 (0.6; p < 0.002) and D28 (0.1; p < 0.002). Similarly, investigator pruritus scale (D0, 2.2) scores significantly decreased on D14 (0.4; p < 0.004) and D28 (0.2; p < 0.002). Conclusions—The combination permethrin-fipronil appears to be well-tolerated, rapidly and durably effective in the control of localized canine harvest mite infestation.

Making Sense of Pharmacovigilance and Drug Adverse Event Reporting: Comparative Similarity Association Analysis Using AI Machine Learning Algorithms in Dogs and Cats

Drug-associated adverse events cause approximately 30 billion dollars a year of added health care expense, along with negative health outcomes including patient death. This constitutes a major public health concern. The US Food and Drug Administration (FDA) requires drug labeling to include potential adverse effects for each newly developed drug product. With the advancement in incidence of adverse drug events (ADEs) and potential adverse drug events, published studies have mainly concluded potential ADEs from labeling documents obtained from the FDA's preapproval clinical trials, and very few analyzed their research work based on reported ADEs after widespread use of a drug to animal subjects. The aforesaid procedure of deriving practice based on information from preapproval labeling may misrepresent or deprecate the incidence and prevalence of specific ADEs. In this study, we make the most of the recently disseminated ADE data by the FDA for animal drugs and devices used in animals to address this public and welfare concern. For this purpose, we implemented 5 different methods (Pearson distance, Spearman distance, cosine distance, Yule distance, and Euclidean distance) to determine the most efficient and robust approach to properly discover highly associated ADEs from the reported data and accurately exclude noise-induced reported events, while maintaining a high level of correlation precision. Our comparative analysis of ADEs based on an artificial intelligence (AI) approach for the 5 robust similarity methods revealed high ADE associations for 2 drugs used in dogs and cats. In addition, the described distance methods systematically analyzed and compared ADEs from the drug labeling sections with a specific emphasis on analyzing serious ADEs. Our finding showed that the cosine method significantly outperformed all the other methods by correctly detecting and validating ADEs based on the comparative similarity association analysis compared with ADEs reported by preapproval clinical trials, premarket testing, or postapproval complication experience of FDA-approved animal drugs.

Treatment of Neotrombicula species infestation in cats using a 10% (w/v) fipronil topical spot-on formulation: a pilot study

Objectives

Few data are available concerning therapeutic aspects of feline trombiculiasis. This study evaluated the efficacy of a 10% w/v fipronil-based spot-on solution in 15 cats with natural Neotrombicula species infestation.

Methods

Ten cats received 1 drop per affected site on day (D)0 and D14, with the rest of the 0.5 ml pipette applied on the skin between the shoulders. Five cats served as non-treated controls. Parasite score (0 = absent; 3 = severe, >10 parasites/zone) was assessed on D0, D14 and D28 on all animals. Skin lesions (SCORing Feline Allergic Dermatitis lesion severity scale [SCORFAD]) and investigator pruritus scale (IPS; 0 = cat comfortable, grooming like any normal cat; 4 = cat uncomfortable, pruritic all the time) were assessed on treated cats on the same days. Global assessment of efficacy, tolerance and ease of use (GAS; 1 = very poor; 5 = excellent) was assessed on D28.

Results

All the cats completed the study. Parasite scores of the control cats were maintained throughout the trial (mean ± SD: D0 4 ± 0.7, D14 3.2 ± 1.1 and D28 3.2 ± 0.4). In treated cats, SCORFAD (D0 3.2 ± 5.4, D14 1.1 ± 2.1 [P <0.002] and D28 0.5 ± 1.3 [P <0.002]), parasite (D0 3.9 ± 1.3, D14 1.2 ± 0.8 [P <0.005] and D28 0.4 ± 0.5 [P <0.005]) and IPS (D0 1 ± 1.2, D14 0.5 ± 1.1 [P <0.05] and D28 0.3 ± 0.7 [P <0.05]) scores significantly decreased throughout the trial. On D28, the GAS was 4.2 ± 0.9. There were no adverse effects from treatment.

Conclusions and relevance

The 10% w/v fipronil preparation appeared to be effective, safe and practical in the treatment of localised Neotrombicula species infestation in these cats.

Efficacy of a new spot-on formulation of selamectin plus sarolaner for cats against adult Ctenocephalides felis, flea egg production and adult flea emergence

A new spot-on formulation of selamectin plus sarolaner was evaluated against fleas for adulticidal efficacy, and for the effect on egg production and hatching when applied to flea-infested cats. Ten male and ten female adult domestic shorthair cats were randomly assigned to one of two treatment groups based on pre-treatment flea counts. Cats received topical treatment on Day 0 in a single spot to the dorsal scapular area with either a placebo formulation or with the combination formulation at the minimal dose of 6.0mg selamectin plus 1.0mg sarolaner per kg bodyweight. On Days -1, 5, 12, 19, 26 and 33, cats were infested with approximately 100 (±5) unfed Ctenocephalides felis fleas. At 24h after treatment or 48h after subsequent flea infestation, cats were housed for a 20-h period in a cage to allow collection of flea eggs. At the end of this period, flea eggs were collected from the cages and cats were combed to remove and count live fleas. Emerged viable larvae and emerged adult fleas were counted 3days and 35days, respectively, after egg collection. The new spot-on formulation of selamectin plus sarolaner provided 100% efficacy against adult fleas up to Day 36 following a single application. Fleas on placebo-treated cats produced large numbers of eggs throughout the study, with individual counts ranging from 110 to 1256 eggs. Following treatment, four flea eggs were collected from a single selamectin/sarolaner-treated cat on Day 29, but there were no eggs collected from any other selamectin/sarolaner-treated animal during the study. No larvae or adult fleas developed from these four eggs. From the eggs collected from the placebo-treated cats, the mean percentage of live larvae and adults that emerged ranged from 67.3% to 84.2% and from 50.7% to 81.8%, respectively. A single topical treatment with a new spot-on formulation of selamectin plus sarolaner at the minimum label dose thus controlled fleas on cats and was 100% effective in preventing flea reproduction for over one month after treatment.

The main factors influencing canine demodicosis treatment outcome and determination of optimal therapy

The main idea of this research was to evaluate the efficacy of canine demodicosis conventional treatments using mathematical analyses. All available papers published between 1980 and 2014 were used in this study. One hundred six clinical trials enrolling 3414 cases of generalized demodicosis in dogs are studied. Dogs entered in the analysis were only the ones in which the disease occurred naturally, excluding the studies in which transplantation of Demodex canis mites was done from other animals. In conventional acaricide treatments, sorted according to active substances (moxidectin, amitraz, doramectin, ivermectin, and milbemycin oxime), the way of application (spot-on, dips, orally, or subcutaneous), concentration, and interval of application were used as input parameters in mathematical modeling. Data of interest were the treatment outcome, the number of dogs that went into remission, the number of animals not responding to treatment microscopically, the average duration of therapy, the follow-up period, the number of patients with disease recurrence, the number of adverse effects, and the number of animals with side effects. Dogs lost to follow-up or when the treatment was discontinued, due to various reasons not in connection with the therapy protocol, were not considered. Statistical and mathematical analyses were applied for prediction of the drugs' effectiveness. Developed mathematical models showed satisfactorily r (2), higher than 0.87. Good evidence for recommending the use of milbemycin oxime PO (0.5 mg/kg, daily) and moxidectin spot-on (Advocate®, Bayer) weekly is found. A bit less effective therapies were based on ivermectin PO (0.5 mg/kg, daily), moxidectin PO (0.35 mg/kg, daily), and amitraz dips (0.05 % solution, weekly), respectively. It is important to keep in mind that Advocate® is recommended by the manufacturer for use in milder cases.

Evaluation of the efficacy of selamectin spot-on in cats infested with Aelurostrongylus abstrusus (Strongylida, Filariodidae) in a Central Italy cat shelter

In recent years Aelurostrongylus abstrusus has often been reported in Italy. This lungworm is very common in cat colonies due to its route of transmission. Deciding a therapeutic approach can be difficult in such colonies, because there is no certainty whether oral medicines administered with food, or with what dose, will be taken. In this field study, stool samples were taken from 42 cats and analysed for A. abstrusus L1 larvae with Baermann technique. Ten cats testing positive were treated with a spot-on formulation of selamectin 45 mg. Clinical examinations and laboratory tests, repeated four times in two months, demonstrated the success of the treatment in 9 of the 10 cats. Improvements in respiratory signs and general clinical condition were reported after treatment.

Fleas infesting pets in the era of emerging extra-intestinal nematodes

Modifications in climatic conditions, movements of hosts and goods, changes in animal phenology and human behaviour and increase of wildlife, are presently concurring in the geographic spread of vectors and cardio-respiratory nematodes, e.g. Dirofilaria immitis, Angiostrongylus vasorum, Aelurostrongylus abstrusus and Capillaria aerophila. All these factors may also influence dispersion and clinical significance of fleas, thus posing relevant challenges in those regions where other parasites are emerging at the same time. Ctenocephalides felis, Ctenocephalides canis and Pulex irritans cause discomfort, nuisance, allergic reactions, anaemia, and may transmit several pathogens, some of them are of importance for public health. The present article reviews the importance of fleas in small animal practice and their sanitary relevance for dogs, cats and humans, and discusses current control methods in the present era of emerging extra-intestinal nematodes, towards a possible changing perspective for controlling key parasites affecting companion animals.

Treatment of MDR1 mutant dogs with macrocyclic lactones

P-glycoprotein, encoded by the multidrug resistance gene MDR1, is an ATP-driven drug efflux pump which is highly expressed at the blood-brain barrier of vertebrates. Drug efflux of macrocyclic lactones by P-glycoprotein is highly relevant for the therapeutic safety of macrocyclic lactones, as thereby GABA-gated chloride channels, which are confined to the central nervous system in vertebrates, are protected from high drug concentrations that otherwise would induce neurological toxicity. A 4-bp deletion mutation exists in the MDR1 gene of many dog breeds such as the Collie and the Australian Shepherd, which results in the expression of a non-functional P-glycoprotein and is associated with multiple drug sensitivity. Accordingly, dogs with homozygous MDR1 mutation are in general prone to neurotoxicity by macrocyclic lactones due to their increased brain penetration. Nevertheless, treatment of these dogs with macrocyclic lactones does not inevitably result in neurological symptoms, since, the safety of treatment highly depends on the treatment indication, dosage, route of application, and the individual compound used as outlined in this review. Whereas all available macrocyclic lactones can safely be administered to MDR1 mutant dogs at doses usually used for heartworm prevention, these dogs will experience neurological toxicity following a high dose regimen which is common for mange treatment in dogs. Here, we review and discuss the neurotoxicological potential of different macrocyclic lactones as well as their treatment options in MDR1 mutant dogs.

Haemaphysalis concinna (Acari: Ixodida): persistent efficacy of selamectin in Angora rabbits under laboratory conditions

In the present study, the persistent efficacy of selamectin (SEL) in Angora rabbits infested with Haemaphysalis concinna was observed. SEL (6 mg/kg) was administered to rabbits with a single topical application. Eighteen Angora rabbits were randomly allocated to three groups of six rabbits each. At days 1, 8, 15, 22, and 29 following SEL administration, rabbits were inoculated with larval, nymphal, and adult ticks and were then observed for a period of 7 days. The cumulative reduction rates at days 1, 8, 15, 22, and 29 for dead ticks were 100%, 100%, 100%, 95.0%, and 76.7%, respectively, for larvae; 100%, 100%, 100%, 85.0%, and 65.0%, respectively, for nymphs; and 100%, 95.0%, 85.0%, 60.0%, and 45.0%, respectively, for adults. The cumulative reduction rates for larvae in untreated Angora rabbits (controls) were 3.3%, 1.7%, 3.3%, 5.0%, and 5.0%, respectively. There was no reduction of nymphs and adults in untreated Angora rabbits (controls). The reduction rates for larvae, nymphs, and adults were significantly higher for Angora rabbits inoculated with SEL than the controls (P < 0.001).

Nasal myiasis in a cat caused by larvae of the nasal bot fly, Oestrus ovis

An 8-year-old desexed male Burmese cat, which lived on a sheep-grazing property in central New South Wales, Australia, was presented following the sudden onset of dyspnoea, moist coughing and violent sneezing. The respiratory distress started several hours after the cat had made an outdoor excursion. Anterior rhinoscopy demonstrated small, white objects moving across oedematous and moderately inflamed nasal mucosa. These were retrieved via a series of vigorous nasal flushes and subsequently identified as larvae of the nasal bot fly, Oestrus ovis. The cat was treated with ivermectin followed by selamectin 7 days later. It went on to make a complete recovery over 2-3 weeks.

Preliminary findings on the efficacy of selamectin in the treatment of dogs naturally infected with Dirofilaria repens

Subcutaneous dirofilariosis caused by Dirofilaria repens is common in dogs and it is an emerging helminthozoonosis in Europe, Asia, Africa and also in Hungary. Macrocyclic lactones are used for preventing the infection; however, their activity against the microfilariae and mature stages of this species is questionable. Selamectin is widely used for the prophylaxis of heartworm (D. immitis) infection. The objective of the present study was to test the microfilaricidal efficacy of the topical formulation of selamectin in dogs naturally infected with D. repens . A total of 78 Beagle dogs were examined for the presence of circulating microfilariae by Knott's test. Twenty-three of the microfilaraemic dogs were divided into four groups and included in the trial. The dogs received monthly or biweekly selamectin treatment and were subjected to monthly blood testing for a period of 252 or 336 days. At the end of the study, 65% of the dogs were not microfilaraemic and the rest had low number of microfilariae in their blood. These results indicate that chronic spot-on selamectin treatment may be a useful tool also in the control of canine subcutaneous dirofilariosis.