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Background: Adult, nymph, and larval Rhipicephalus sanguineus sensu lato infest dogs and thrive in premises including homes and kennels. Ticks emerge from hiding to seek and attach to dogs, engorge, then leave their hosts to hide then molt or oviposit. This study evaluated the effect of either external or systemic canine treatment on R. sanguineus s.l. populations in premises., Methods: Thirty-two dogs in eight kennels were divided into three groups; one group (eight dogs in two kennels) served as untreated controls; one group (12 dogs in three kennels) received oral fluralaner (25-56 mg/kg); and one group (12 dogs in three kennels) received topical flumethrin/imidacloprid impregnated collars. Treatments were administered once on day 0. Prior to treatment, R. sanguineus s.l. infestations were established in kennels holding dogs, by placing ticks every 2 weeks from day -84 through day -14. Kennel surfaces (walls and floors) were smooth except for uniform "hideouts" to permit precise off-host tick counting., Results: Control dog kennel mean tick counts (all life stages) increased from 737 ticks/kennel at day -7 to 2213 at day 63 when all control kennel dogs were acaricide-treated as a humane endpoint. Kennels housing dogs subsequently treated with systemic fluralaner had a mean of 637 counted ticks/kennel on study day -7 (7 days before treatment). One fluralaner treatment eliminated all premises ticks (100% reduction) by day 70, and these kennels remained tick-free through study completion (day 84). Kennels housing dogs subsequently treated with an external imidacloprid/flumethrin collar had a mean of 614 counted ticks/kennel at study day -7. Collar treatment reduced counts by 90% on day 63, with kennel tick counts climbing after this and ending the study with a 75% reduction. Systemic fluralaner treatment was significantly (P = 0.003) more effective at reducing engorged adult female tick counts than external imidacloprid/flumethrin treatment., Conclusions: Fluralaner treatment eliminated off-host R. sanguineus life stages in infested kennels by day 70 following treatment and was significantly more effective than imidacloprid/flumethrin collar treatment in reducing the premises population of engorged female ticks. Imidacloprid/flumethrin treatment did not eliminate premises tick populations, with populations increasing before the study end., (© 2023. © Merck & Co., Inc., Rahway, NJ, USA and its affiliates 2023.)

On Linosa Island, Italy, Dirofilaria immitis infection has been hyperendemic in dogs and seroprevalent among islanders. In 2020, we implemented a heartworm disease elimination program on Linosa Island. Of 54 dogs tested for D. immitis antigen and microfilariae, 28 had positive results and received treatment with oral doxycycline twice daily for 4 weeks plus topical imidacloprid/moxidectin monthly for 12 months. The 26 dogs with negative results received monthly topical imidacloprid/moxidectin as preventive. During month 1, the number of microfilaremic dogs was reduced by 76.5%. From month 2 on, all animals were microfilariae negative, and during months 3 to 9, the number of antigen-positive dogs decreased progressively. Treatment of positive dogs coupled with chemoprophylaxis for noninfected dogs was effective, protecting them from new infections. The elimination program reduced the risk for human infection, representing a One Health paradigm. Monitoring and chemoprophylaxis are advocated to maintain the status of heartworm disease-free area.

Phytoremediation is an effective remediation process for heavy metal contamination. The primary zone of phytoremediation is the rhizosphere where the plants uptake the heavy metals from the soil matrix. The bioavailability of the contaminants in the rhizosphere is affected by the physical, chemical, and biological conditions of the rhizosphere. In the study area of the Apalachicola National Forest, the concentrations of As, Pb and Cr in the bulk soil (n = 20) were 515.81, 220.77, and 2.02 mg/kg soil, respectively. Using a sequential extraction method, the bioavailability of heavy metals in the bulk soil (S-NR) and rhizosphere soil (S-R) was characterized. The results showed that the bioavailability of the three heavy metals had the order of Cr > Pb > As for S-NR and Pb > As > Cr for S-R. The bioavailability of these metals was affected by the nature of the heavy metals and the soil physicochemical properties. Native plant Eriocaulon decangulare could uptake a large number of heavy metals from the natural soil, demonstrating great phytoremediation potential for metal contamination. Energy Dispersive Spectroscopy (EDS) mapping successfully located the dominant accumulation of heavy metals in aerial parts of E. decangulare. E. decangulare was also found to be highly selective and Pb and As were both extensively accumulated in the shoots and roots. Cr was significantly immobilized in the rhizosphere soil, and also accumulated in the root of E. decangulare. This study not only correlated the phytoremediation potential with heavy metal bioavailability and soil physicochemical properties, but also demonstrated the important role of the nature of heavy metals played during the phytoremediation., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2022. Published by Elsevier B.V.)

Background: The local distribution of helminths in dogs and cats and the evaluation of risk of contamination represent an important challenge for veterinarians due to their effects on animal health and their potential zoonotic risk. The overall goal of this study was to estimate the prevalence of the digestive and respiratory helminths infecting client-owned dogs and cats in France., Methods: Faecal samples were collected from 414 pet dogs and 425 pet cats at 20 study sites during 2017-2018 and analysed by coproscopy. The samples included specimens collected from animals of both genders and various breeds and ages from a variety of living environments, and with different lifestyles and feeding regimes. Associations between parasitic infection and qualitative factors were explored., Results: Overall, 125 (14.9%) samples (15.2% in dogs and 14.6% in cats) were positive for at least one of the species of helminths identified. Infection rates were highest for Toxocara canis and Toxocara cati (8.5% and 11.3%, respectively), while Toxascaris leonina was found only in one cat (0.2%). The apparent prevalence of Ancylostoma caninum and Uncinaria stenocephala in dogs was 1.7% and 4.3%, respectively. No hookworms were found in cats. Whipworms (Trichuris vulpis) were identified in 2.7% of the dogs. Tapeworms (Dipylidium caninum and Taeniidae) were rarely found (< 1% in dogs and < 3% in cats). The prevalence of Angiostrongylus vasorum Crenosoma vulpis, and Strongyloides stercoralis in dogs, Aelurostrongylus abstrusus in cats and Eucoleus spp. / Capillaria spp. in both dogs and cats was < 1%. Significantly higher fecal parasite emission rates were identified in young individuals, in animals with outdoor access, in animals living in the countryside and in intact animals (especially in cats). In addition, cats not fed exclusively with commercial diets and living with other animals (dogs and/or cats) were at higher risk for parasites. For dogs, hunting/herding and walking off-leash were found to be additional risk factors. Furthermore, pets with no reported history of deworming or dewormed > 1 year before the study were positive for parasites significantly more often than pets dewormed < 1 year before study participation., Conclusions: The overall prevalence of helminths (some of which are zoonotic), the risk factors and the reportedly low deworming frequencies identified in this study (20.5% animals having never been dewormed and only 26.4% dewormed ≥ 3 times/year) illustrate the need for improving pet owners' adherence to anthelmintic guidelines in France., (© 2022. The Author(s).)

Background: Intestinal parasite contamination from infected dogs can place other dogs and humans at risk. A study was initiated to estimate the prevalence of canine intestinal parasitism by collecting fecal samples in cities across Western Europe., Methods: Fresh fecal samples were collected from 2469 dogs visiting 164 parks in 33 cities across 12 countries. Each owner responded to a questionnaire focusing on their dog's signalment and recent anthelmintic treatment history. The collected samples were examined for hookworms, whipworms, ascarids and Giardia using a coproantigen diagnostic immunoassay and microscopy following centrifugal flotation., Results: Nematodes or Giardia were detected in at least one sample from 100% of cities and in 93.3% of parks. Nematodes were detected in 57% of parks. Overall, 22.8% of dogs tested positive for an intestinal parasite, with Giardia being the most commonly identified parasites (17.3% of dogs, 83.5% of parks). For nematode infection, 7.6% of all dogs tested positive, with 9.9% of dogs aged < 1 year infected, 7.7% of those aged 1-3 years, 7.3% of those aged 4-6 years and 6.6% of those aged ≥ 7 years. Among the nematodes detected, ascarids were the most prevalent (3.6% of dogs, parks, 28.7% of parks), being most common in dogs aged < 1 year but also present in older dogs, including those aged ≥ 7 years. Hookworms and whipworms were detected in 3.2% and 2.3% of dogs of all ages, respectively, and in 37.2% and 17.7% of parks, respectively. A larger proportion of fecal samples tested positive with the coproantigen immunoassay than with centrifugal flotation. Positive test results for Giardia were sevenfold higher when both diagnostic tests were used than when centrifugal flotation alone was used, and there were 60% more positive test results for nematodes when both tests were used than when flotation alone was used. Overall, 77.2% of owners reported previous anthelmintic treatment, among whom at least 62.7% failed to follow recommended treatment frequency. Dogs receiving anthelmintic within the previous month had a lower percentage of nematode infection than those in which > 1 month had passed since the previous dose., Conclusions: The prevalence estimates of intestinal parasite infections in dogs reported here highlight the need for owner education concerning guidelines for regular testing and treatment, even in older dogs. Failure to adhere to guidelines can result in ongoing transmission of these infections, including those with zoonotic potential. Combining coproantigen immunoassay with centrifugal flotation for diagnostic testing and regular anthelmintic treatment are important measures for ensuring optimal intestinal parasite control., (© 2022. The Author(s).)

Canine angiostrongylosis by Angiostrongylus vasorum is increasingly reported in both enzootic and previously free areas. The complex pathogenesis of the disease makes the clinical workup challenging. Infected dogs show highly variable clinical pictures, characterized by subclinical to life-threatening general, cardio-respiratory, neurological and/or gastrointestinal signs. The present study reports the high variability of clinical pictures from 36 dogs across central and southern Italy that were naturally infected by A. vasorum . Of them, 23 (63.9%) presented at least one clinical sign, while 13 (36.1%) were subclinically infected and apparently healthy. Overall, 19 dogs (52.8%) showed cardiorespiratory signs, 14 (38.9%) had non-specific abnormalities, 2 (5.6%) presented coagulation disorders and 1 (2.8%) had a severe neurological condition. Importantly, four dogs presenting with clinical signs had neither cough nor dyspnea. These results underline that angiostrongylosis should be included in the differential diagnosis, even when dogs display only non-specific clinical signs. The proportion of apparently healthy dogs highlights the relevance of routine copromicroscopic and/or antigenic tests in enzootic areas to avoid the sudden onset of potentially life-threatening signs.

These guidelines are intended to provide an in-depth review of current knowledge and assist the planning and implementation of studies for evaluating the efficacy of parasiticides in reducing transmission of vector-borne pathogens (VBPs) to dogs and cats. At present, the prevention of VBP transmission in companion animals is generally achieved through the administration of products that can repel or rapidly kill arthropods, thus preventing or interrupting feeding before transmission occurs. The present guidelines complement existing guidelines, which focus on efficacy assessment of parasiticides for the treatment, prevention and control of flea and tick infestations, but also give guidance for studies focused on other vectors (i.e. mosquitoes and phlebotomine sand flies). The efficacy of parasiticides in reducing VBP transmission can be evaluated through laboratory or field studies. As such, the present guidelines provide recommendations for these studies, representing a tool for researchers, pharmaceutical companies and authorities involved in the research, development and registration of products with claims for reducing VBP transmission in dogs and cats, respecting the overall principles of the 3Rs (replacement, reduction and refinement). Gaps in our current understanding of VBP transmission times are herein highlighted and the need for further basic research on related topics is briefly discussed., (Copyright © 2021. Published by Elsevier B.V.)

Background: Animal rescue and animal welfare organizations are relocating thousands of dogs per year following natural disasters and in attempts to provide greater adoption opportunities. Many dogs are sourced from the southeastern USA, which historically has a high prevalence rate for many parasites and parasitic diseases. The Colorado Department of Agriculture Pet Animal Care Facilities Act (PACFA) requires animal shelters and animal welfare organizations to report annually a variety of statistics including the numbers of dogs imported into Colorado from out of state. The Companion Animal Parasite Council (CAPC) provides data nationally, down to the state and county level, on a variety of common parasitic and vector borne diseases. These data make it possible to track changes in parasite prevalence over several years., Methods: Test results for canine roundworm, hookworm and whipworm were collected from the CAPC maps for 2013-2017. Dog importation data for 2014-2017 was collected from PACFA reports. For evaluation of the statistical significance of prevalence changes when comparing 2013 to 2017, 2 × 2 contingency tables were constructed with both positive and negative test results for each year and the data assessed using Chi-square tests to determine if the 2017 prevalence was significantly different than the 2013 prevalence for roundworm, hookworm and whipworm., Results: Significant increases in intestinal nematode prevalence occurred in Colorado from 2013 to 2017. The prevalence of canine roundworm rose 35.60%, the prevalence of canine hookworm rose 137.33% and the prevalence of canine whipworm rose 63.68%. From 2014 to 2017, over 114,000 dogs were transported into Colorado from out-of-state, by more than 130 animal shelters and rescue organizations. Three of the larger organizations reported that the majority of their dogs were obtained from New Mexico, Texas and Oklahoma. Texas and Oklahoma have historically much higher parasite prevalence than Colorado., Conclusions: Veterinarians in areas with historically low parasite prevalence where dogs from high parasite prevalence areas are arriving for adoption may need to reevaluate their recommendations regarding fecal examination and deworming frequencies as historic levels of intestinal parasite infection may no longer be accurate assessments of future infection risks.

Background: Dogs and cats in the UK are exposed to many internal parasites which can pose risks to the health of both the pet and their owners. By understanding these endemic parasites and the risks they pose, we can assess the lifestyle of pets and recommend the correct deworming frequency. Studies identifying risk factors were discussed in the European Scientific Counsel Companion Animal Parasites (ESCCAP) guidelines. To this date, there has been very little information on how pet owners in the UK deworm their pets and if the protocols they follow align with ESCCAP recommendations. The objective of this study was to look at the current deworming protocols of UK cat and dog owners in conjunction with their lifestyle and risk., Methods: An online survey was conducted in the UK targeting pet owners who own at least one dog and/or cat and were responsible for product purchase, the pet's health care and veterinary visits. These survey results were analysed against the ESCCAP guidelines and each pet placed into a risk category. By comparing the current deworming frequency with that recommended for their risk category, the compliance of UK pet owners with ESCCAP recommendations was evaluated., Results: A total of 500 dog owners and 500 cat owners completed surveys. Overall, the study found none of the pets fell into risk group A, with all pets meeting the risk level for at least deworming four times a year (risk group B and above). The majority of animals fell into the highest risk category D with 97% of dogs and 68% of cats. The average deworming per year in the UK was 3.1 for dogs and 3.1 cats, below the minimum recommended by ESCCAP., Conclusions: For both felines and canines, the dosing frequencies are lower than recommended to both reduce zoonotic risk for reducing Toxocara spp. egg-shedding and improve pet health. This research highlights the need for improved education around dog and cat patient risk assessments and greater adherence to recommended deworming aligned with the ESCCAP guidelines.

Background: Pets may be carriers of infectious agents including parasites. As part of a larger-scale study covering the whole of Europe, this study examines deworming measures reported by Spanish pet owners and identifies risk factors., Methods: An online questionnaire was administered to cat and dog owners in Spain. The replies provided were used to obtain information about the pets' living conditions and to accordingly classify each pet into one of the four ESCCAP infection risk categories (A, B, C or D) for which different deworming frequencies are recommended. Questions were also asked about pet care and owners' attitude toward their pets. The Kruskal-Wallis test was used to correlate risk groups with deworming frequencies., Results: Completed questionnaires were returned by 500 cat owners and 501 dog owners. According to responses, 96.21% of dogs were assigned to risk category D (maximum risk), and only 1.2%, 2.2% and 0.4% to A, B and C, respectively. Almost all cats were assigned to the minimum risk category A (indoor cats, 62%) or maximum risk category D (outdoor cats, 32.8%); only 3.4% and 1.8% of cats were classified as risk B and C respectively. More dogs were allocated to the higher risk group compared to cats, which were more frequently kept indoors. Cats were reportedly dewormed less frequently than dogs (2.56 and 3.13 times per year respectively), consistent with their different infestation risk. Thus, pets in the lower risk group A were either adequately dewormed or treated more often than necessary. Only a small proportion of cats were not dewormed at all (n = 14). Alarmingly, almost all pets in risk groups B, C or D (representing 95% of dogs and 39% of cats) were dewormed less often than recommended., Conclusions: More effective health education is required for the management of zoonotic endoparasite diseases under the umbrella of One Health targeted at owners, veterinarians, general practitioners, and health authorities. To align deworming frequency with infection risk, pet owners should be provided with clear, compelling instructions.

Background: Endoparasites in dogs and cats are a concern related to pet health and zoonotic risks. Several determinants may affect the endoparasite transmission and infection of dogs and cats such as pet's lifestyle or regional parasite distribution. Although different zoonotic endoparasites, such as Toxocara spp. and Echinococcus spp., have been identified in France, little information exists about the deworming behaviors of owners or the frequency of occurrence of risk factors associated with endoparasite infection or transmission. Deworming guidelines, such as those created by the European Scientific Counsel Companion Animal Parasites (ESCCAP), recommend a deworming frequency according to the risk of infection of every pet and the potential risk for zoonotic transmission. The objectives of this study were to explore how lifestyles of dogs and cats from France were related to a particular risk of endoparasites and assess whether deworming frequencies complied with ESCCAP recommendations., Methods: French data were extracted from a database created during a recent European pet owner survey regarding endoparasitic infection risk. Dogs and cats were grouped into risk categories based upon the ESCCAP guidelines. The compliance between the actual and recommended deworming frequencies were explored among the regions surveyed., Results: The majority of dogs and cats were older than 6 months, had outdoor access, had contact with children or elderly people, and lived in rural and town areas. Most of the dogs were in contact with other dogs, snails or prey (83%), and ate slugs, snails, grass or dug in the garden (68%). Likewise, most of the cats hunted outside (57%) and caught prey animals (52%). Consequently, most of the dogs (89%) and cats (53%) were considered to be in the highest-risk category (D). However, independent of the region, the average deworming compliance for dogs was poor (6%). While deworming compliance for cats in category A (low-risk) was excellent (94%), for cats in category D it was poor (6%)., Conclusions: Deworming compliance is needed to enhance pet health and reduce zoonotic risks. Future studies are warranted to thoroughly investigate the compliance and effectiveness of deworming protocols, and the risk factors associated with endoparasites in France.

Background: The three most commonly diagnosed gastrointestinal parasites of pet dogs within the USA are the whipworm, the hookworm, and the roundworm. The collection of large data sets from various sources throughout the industry have produced a number of publications on parasite prevalence in recent years. In this study, we look at data captured by the Companion Animal Parasite Council from 2012-2018, which includes 4.3-7.2 million annual fecal exams, to evaluate not only changes in prevalence, but also possible seasonal fluctuations of the three most common canine gastrointestinal parasites., Methods: Annual and monthly data were collected from the CAPC parasite prevalence maps for canine roundworms, hookworms and whipworm. The map data were provided to CAPC by two large national reference laboratories. The data were evaluated for changes in prevalence on a monthly basis throughout each year as well as changes in prevalence from year to year from 2012-2018. Additionally, positive test results and total tests performed for each of the three parasites from 2012-2018 during individual months were totaled without using the year as a variable in order to evaluate the results for seasonality (i.e. all tests and positive results occurring in January, regardless of year, were totaled and analyzed)., Results: Evaluation of gastrointestinal nematode prevalence data from over 39 million fecal samples examined over a 7-year period revealed a subtle, yet significant, increasing prevalence for roundworms, an increasing prevalence for hookworms, and a slightly decreasing prevalence for whipworms. Seasonality was demonstrated for roundworms, hookworms, and to our knowledge, for the first time canine whipworms. Highest seasonal prevalence for roundworms, hookworms, and whipworms occurred during December-January, July-August, and January-February, respectively., Conclusions: Evaluation of monthly gastrointestinal parasite prevalence data from over 39 million fecal samples collected over a 7-year period revealed a slightly increasing prevalence for roundworms, an increasing prevalence for hookworms, and a slightly decreasing prevalence for whipworms. In addition to the annual changes in prevalence, seasonal prevalence was shown for the first time for whipworms. Prevalence of both whipworm and roundworm peaked in the winter, while prevalence of hookworm peaked in the late summer and early autumn.

Background: Animal welfare organizations, in order to increase dog adoptions and reduce euthanasia of homeless dogs, are transporting large numbers of dogs from state-to-state. Only approximately 1/3 of animal welfare organizations reportedly test for heartworm infection, treat, or provide heartworm prevention prior to transporting dogs. The reported prevalence of heartworms in dogs in animal shelters or rescued following natural disasters ranges between 14.6-48.8%. This analysis was conducted to evaluate the correlation between dog importation and heartworm prevalence in dogs in Colorado., Methods: Data were obtained from the Companion Animal Parasite Council (CAPC) interactive heartworm prevalence maps and the Colorado Department of Agriculture Pet Animal Care Facilities Program (PACFA) in order to analyze the relationship between dog importation and the changes in prevalence of heartworm (Dirofilaria immitis) in Colorado from 2013 to 2017., Results: The prevalence of heartworms in Colorado dogs has increased 67.5% between 2013-2017. From 2014 to 2017, more than 114,000 dogs were imported into Colorado by over 130 animal shelters and rescue organizations, which could represent approximately 9.5% of the total estimated 2017 Colorado dog population of nearly 1.2 million dogs. Three large Colorado-based organizations responded to requests for details regarding the originating states from which they received dogs. The majority of these dogs were apparently shipped to Colorado from states with higher heartworm prevalence. New Mexico represented the source of the greatest number of relocated dogs, accounting for just over 30%. Nearly half (49%) of the dogs relocated by these three organizations came from either Texas or Oklahoma., Conclusions: Animal welfare organizations and veterinarians should increase the testing and prevention of heartworm infections in dogs both prior to, and following, transportation from areas with high heartworm prevalence. Repeated testing is recommended due to the 6-month pre-patent-period associated with D. immitis. Veterinarians and pet owners should increase vigilance with heartworm testing and prevention, even in areas with historically low heartworm prevalence. Movement of dogs from highly endemic areas may increase the risks of local transmission.

Background: Zoonotic endoparasites pose risks to pets and people. The European Scientific Counsel Companion Animal Parasites (ESCCAP) created risk groupings for dogs (A-D) and for cats (A-B), with the highest risk pets (Group D dogs and Group B cats) receiving the most frequent testing and/or deworming recommendations. Little information exists on current deworming behaviours across Europe, alignment to accepted guidelines and the percentage of dogs and cats falling into ESCCAP groups. The study objectives were to evaluate the reported infection-risk behaviours of dogs and cats and assesses whether deworming frequency reported by pet owners complied with recommended deworming frequencies., Methods: A total of 5001 pet owners from five different countries (France, Germany, Spain, Sweden and the UK) were surveyed regarding endoparasite infection risk and the frequency of deworming of dogs and cats. For the purposes of this study, ESCCAP risk groups for cats (A-B) were converted into four risk groups (A-D) using the additional risk factors outlined in the ESCCAP guidelines. This allowed direct comparison between cats and dogs as well as grouped higher risk cats into the appropriate deworming frequency., Results: The three most common risk factors identified for dogs were contact with: other dogs, snails or prey; children or the elderly; going off lead outside their own garden. 85-98% of all dogs had risks putting them into Group D, the highest risk group. The three most common risk factors identified for cats were: hunting; catching prey; contact with children or the elderly. Using these revised groups, 33-68% of cats were in Group D. Despite the majority of dogs and cats falling into a risk category where ESCCAP recommends monthly deworming, dogs and cats averaged 2.3 and 2.2 dewormings per year, respectively. This frequency was less than the four times a year dosing frequency demonstrated to be required to reduce zoonotic Toxocara spp. ova shedding., Conclusions: Overall, 93% of dogs and 54% of cats fell into Group D, the highest risk group. Deworming frequencies were considerably less than recommended by ESCCAP or required to both reduce zoonotic risk and improve pet health. Improved treatment compliance is needed.

Background: The ixodid tick Amblyomma cajennense (sensu lato) complex, widespread throughout South and Central America, is also present in Mexico, Texas and Florida. As a vector of Rickettsia rickettsii, and potentially of other pathogens, infestations with A. cajennense present a substantial health risk to humans, dogs and other mammals. Oral administration of lotilaner flavored chewable tablets (Credelio TM , Elanco) to dogs was previously shown to rapidly provide killing activity of infesting ticks. This study investigated lotilaner's efficacy against A. cajennense (s.l.)., Methods: Twenty purpose-bred Beagles (10 male and 10 female) were ranked by Day -5 burdens of nymphal A. cajennense (s.l.) and randomized to either treatment with lotilaner or to a sham-treated control group. On Day 0, dogs were fed within approximately 30 min prior to oral lotilaner administration at as close as possible to 20 mg/kg, the minimum dose rate. For efficacy assessments, tick counts were completed 48 h post-treatment or 48 h after experimental challenge infestations with 200 nymphal A. cajennense (s.l.) on Days -7, -2, 7, 14, 21 and 28., Results: Tick infestations in the control group dogs ranged from a low of 43 to 95, with the average infestation remaining above 25% at each assessment, thereby meeting the requirement for efficacy comparison with the treated group. Lotilaner efficacy was 100% within 48 h post-treatment, and at nine days post-treatment. Efficacy was greater than 99% at all subsequent assessments through Day 30. No treatment-related adverse events were observed., Conclusion: The results demonstrate that lotilaner, administered orally to dogs at a minimum dose of 20 mg/kg is well tolerated, provides rapid reduction of existing A. cajennense (s.l.) tick infestations, and provides sustained residual protection for at least 30 days against subsequent infestation by A. cajennense (s.l.).

Background: From three days following host attachment, the Australian paralysis tick, Ixodes holocyclus, secretes a neurotoxin that annually causes paralysis in approximately 10,000 domestic pets. Lotilaner, a novel isoxazoline formulated in a chewable flavoured tablet (Credelio TM ), produces rapid onset of acaricidal activity in dogs, with an efficacy duration of at least one month. Two studies were performed to determine the efficacy of lotilaner against I. holocyclus infestations over 3 months., Methods: Both studies included 16 dogs, ranked according to I. holocyclus counts on Day -5 (from infestations on Day -8) and blocked into pairs. One dog in each pair was randomized to be a sham-treated control, the other to receive lotilaner at a minimum dose rate of 20 mg/kg on Day 0. Dogs were dosed in a fed state. Infestations were performed in both studies on Days -8 (to determine the tick carrying capacity of each dog) -1, 28, 56, 70, 77 and 84, and additionally in Study 1 on Day 91, in Study 2 on Days 14 and 42. In Study 1, ticks were counted and assessed as alive or dead at 24, 48 and 72 h post-initial infestation and post-subsequent re-infestations. In study 2, ticks were counted at 24, 48 and 72 h post-dosing or post-re-infestation. Efficacy was determined by the percent reduction in live attached tick counts in the lotilaner group compared to control., Results: Within 48 h post-treatment in Study 1 and within 72 h post-treatment in Study 2 all lotilaner-group dogs were free of live ticks. By 72 h post-infestation, efficacy in Study 1 remained at 100% through Day 87, except on Day 31 when a single tick was found on one dog, and through Day 59 in Study 2. Efficacy exceeded 95% through the final assessment in each study (Days 94 and 87 in Studies 1 and 2, respectively)., Conclusion: These results demonstrate that lotilaner quickly kills existing I. holocyclus infestations. By providing 95.3-100.0% protection through at least 87 days post-treatment, lotilaner can be a valuable tool in reducing the risk of tick paralysis in dogs.

Background: Throughout Japan, Korea and China, Haemaphysalis longicornis ticks are vectors of Babesia gibsoni, which causes severe and progressive anemia in dogs. This study evaluated the efficacy of a single administration of lotilaner flavored chewable tablets (Credelio TM ) against experimental canine H. longicornis infestations., Methods: Twenty-two healthy Beagles were ranked in descending order of counts of H. longicornis completed 48 h after challenge on Day -7. The 16 dogs with the highest live tick counts were blocked into pairs and within pairs randomized to either lotilaner-treatment at a minimum dose rate of 20 mg/kg or sham-treated controls. Treatment was administered within 30 ± 5 min following feeding on Day 0. Infestations with 50 unfed adult H. longicornis were completed on Days -2, 7, 14, 21, 28 and 35. Elizabethan collars were placed for 48 (± 2) h after each infestation and a T-shirt was placed on each dog to facilitate attachment. Ticks were counted in situ 12 and 24 h post-treatment and counted and removed after an additional 24 h (48 h after treatment) and 48 h after each post-treatment infestation. Dogs were sedated for tick challenges and counts. Live attached ticks on each dog were counted for efficacy assessments. Lotilaner was considered effective if the average tick attachment rate in the control group was at least 20%, if there was a statistically significant difference (P < 0.05) in mean tick counts between treated and control groups, and if the lotilaner-treated group had a calculated efficacy of at least 90%., Results: Average control group retention of the H. longicornis challenge exceeded 20% at each assessment. Lotilaner started killing H. longicornis ticks quickly, achieving 57.4% efficacy within 12 h. At 48 h post-treatment, and following each subsequent infestation, between-group differences in mean H. longicornis counts were significant (P < 0.0001). From 48 h post-treatment, through the final assessment on Day 37, lotilaner efficacy remained greater than 95%, including on Day 37 when efficacy was 98.4%., Conclusion: Lotilaner, administered to dogs orally at a minimum dose rate of 20 mg/kg is well tolerated, provides rapid reduction of existing H. longicornis tick infestations, and provides sustained residual protection for at least 35 days.

Background: Lotilaner, approved for dogs as a chewable tablet formulation, has separately been developed for oral use in cats (Credelio TM chewable tablets for cats), to meet the need for an easy to use, safe and rapidly effective parasiticide. It is a valid cat- and owner-friendly alternative to topical products. This manuscript describes three pivotal laboratory studies assessing the efficacy and speed of kill of lotilaner in cats against Ixodes ricinus ticks following a single oral administration, at a dose rate close to 6 mg/kg., Methods: In Studies 1 and 2, efficacy and safety were evaluated 48 h after treatment and post-treatment weekly infestations in 16 cats, against untreated controls, for 35 days. In Study 3, efficacy and safety were assessed in 8 lotilaner-treated cats until Day 35, before and after 24 h incubation of the female live ticks removed from the animals 12, 18 and 24 h after dosing and subsequent weekly infestations., Results: Efficacy was > 99% on days 23 and 37, and 100% on all other timepoints in Study 1. In Study 2 it was > 98% on Days 9 and 37, and 100% on all other days. In Study 3, on Day 0, lotilaner was > 90% efficacious, pre- and post-incubation at all time-points. On Day 7, at 12 hours after infestation, efficacy was 100%, pre- and post-incubation. On Day 14, there was a 66.5% reduction in geometric mean live tick counts in treated cats compared to controls, increasing, after incubation, to 94.4%. Afterwards, efficacy decreased below 90% while tick counts in the treated groups remained significantly lower compared to controls. At 18 hours, lotilaner was ≥ 90% efficacious through Day 37, increasing to 100% at 24 hours, on all study days, with the exception of Day 28 (98.9 and 99.1% pre- and post-incubation, respectively). There were no treatment-related adverse events., Conclusions: At the minimum dose rate of 6 mg/kg, lotilaner was efficacious against I. ricinus ticks. In addition, lotilaner was effective against this tick within 12 hours of treatment, reaching 100% efficacy within 24 hours. Lotilaner sustained a rapid kill of newly infesting I. ricinus through 35 days. By quickly killing ticks that infest cats, lotilaner has the potential to contribute to the reduction of tick-borne pathogens transmission.

Background: A recent American Heartworm Society (AHS) survey on the incidence of adult heartworm infections in dogs in the United States of America showed a 21.7% increase in the average cases per veterinary clinic from 2013 to 2016. The analysis reported here was performed to see if heartworm testing results available via the Companion Animal Parasite Council (CAPC) aligned with the AHS survey and whether changes in heartworm preventive dispensing accounts for the increased incidence. The resistance of Dirofilaria immitis to macrocyclic lactones (MLs) has been previously reported., Methods: An analysis of 7-9 million heartworm antigen tests reported annually to the Companion Animal Parasite Council (CAPC) from 2013 to 2016 was conducted and compared to the 2016 AHS survey. A state-by-state analysis across the southeastern USA was also performed. National heartworm preventive dispensing data were obtained from Vetstreet LLC and analyzed. All oral, topical and injectable heartworm preventives were included in this analysis, with injectable moxidectin counting as six doses., Results: Positive antigen tests increased by 15.28% from 2013 to 2016, similar to the 21.7% increase reported by the AHS survey. Incidence in the southeastern USA increased by17.9% while the rest of USA incidence increased by 11.4%. State-by-state analysis across the southeastern USA revealed an increased positive test frequency greater than 10% in 9 of 12 states evaluated. During this time, the overall proportion of dogs receiving heartworm prophylaxis remained relatively unchanged. Approximately 2/3 of the dogs in the USA received no heartworm prevention each year., Conclusion: These CAPC data show the rate of positive heartworm tests increasing significantly (P <  0.0001) in the USA from 2013 to 2016, with a higher rate of increase in the southeastern USA than nationally. Only 1/3 of dogs in the USA were dispensed one or more doses of heartworm prevention annually by veterinarians, averaging 8.6 monthly doses/year. Veterinarians and pet owners should work together to follow CAPC and AHS guidelines to protect dogs from infection with D. immitis. Lack of preventive use and the emergence of heartworm resistance to MLs could both be impacting the increased rate of positive heartworm tests in dogs.

Intestinal helminths are common in dogs in the United States, particularly non-treated dogs in animal shelters, but surveys by fecal flotation may underestimate their prevalence. To determine the prevalence of intestinal helminths and evaluate the ability of fecal flotation and detection of nematode antigen to identify those infections, contents of the entire gastrointestinal tract of 97 adult (>1year) dogs previously identified for humane euthanasia at two animal control shelters in northeastern Oklahoma, USA, were screened. All helminths recovered were washed in saline and fixed prior to enumeration and identification to genus and species. Fecal samples from each dog were examined by passive sodium nitrate (SG 1.33) and centrifugal sugar solution (SG 1.25) flotation. Fecal antigen detection assays were used to confirm the presence of nematode antigen in frozen fecal samples from 92 dogs. Necropsy examination revealed Ancylostoma caninum in 45/97 (46.4%), Toxocara canis in 11/97 (11.3%), Trichuris vulpis in 38/97 (39.2%), Dipylidium caninum in 48/97 (49.5%), and Taenia sp. in 7/97 (7.2%) dogs. Passive fecal flotation identified 38/45 (84.4%) A. caninum, 6/11 (54.5%) T. canis, 26/38 (68.4%) T. vulpis, 2/48 (4.2%) D. caninum, and 1/7 (14.3%) Taenia sp. infections, while centrifugal flotation combined with antigen detection assays identified A. caninum in 97.7% (43/44), T. canis in 77.8% (7/9), and T. vulpis in 83.3% (30/36) of infected dogs based on necropsy recovery of nematodes. Taken together, these data indicate that detection of nematode antigen is a useful adjunct to microscopic examination of fecal samples for parasite eggs, and that this approach can improve diagnostic sensitivity for intestinal nematode infections in dogs., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: The "susceptibility gap" in a dog diagnosed with adult heartworms has been defined as the period of time in which some Dirofilaria immitis stages are not susceptible to treatment with either macrocyclic lactones or melarsomine dihydrochloride. This was previously defined within the American Heartworm Society guidelines as a period of about 3 months "as per product labels." It can be postulated, however, that a susceptibility gap does not exist with the combination of continued macrocyclic lactone therapy coupled with a three-dose melarsomine dihydrochloride protocol where the first intramuscular treatment is near the time of first diagnosis., Discussion: Melarsomine dihydrochloride was originally also investigated as a "preventive" as well as a treatment for adult heartworm infection where it would be given to dogs by intramuscular injection every 4 months; therefore, there was early interest in its ability to kill younger worms. A single intramuscular injection of 2.5 mg melarsomine dihydrochloride/kg has an efficacy of 82.1% against 4-month-old worms. When it was given to dogs with older heartworms, 7 and 12 months of age, a single injection was only 55.6% and 51.7% effective, respectively. Thiacetarsamide has been shown to be 99.7% effective against 2-month-old heartworms and other work has shown that melarsomine dihydrochloride is 100% efficacious against these younger forms. With the development and US Food and Drug Administration (FDA) approval of spinosad + milbemycin oxime (Trifexis®, Elanco), milbemycin oxime + praziquantel (Interceptor® Plus, Novartis, now Elanco), and milbemycin oxime + lufenuron + praziquantel (Sentinel® Spectrum®, Novartis, now Virbac), it was shown that repeated treatments of dogs with milbemycin oxime also has efficacy against 3-month-old heartworms. Thus, no improvement in efficacy is expected with a delay in initiating therapy with both melarsomine dihydrochloride and macrocyclic lactones, even with the presence of younger heartworms. Starting treatment at diagnosis appears to be acceptable for maximal heartworm clearance based on published data. Delaying treatment has the disadvantage of allowing disease progression and continued heartworm growth., Conclusions: The collective data that has been reviewed indicates that continued macrocyclic lactone administration with two additional injections of melarsomine dihydrochloride a month later will protect dogs against all heartworm stages, including those heartworms 2 months of age or younger at diagnosis, when both treatments are started upon diagnosis.

Background: Oral administration of lotilaner flavoured chewable tablets (Credelio™, Elanco) to dogs has been shown to provide a rapid onset of killing activity of infesting ticks, with sustained efficacy for at least 35 days. A study was undertaken in Europe to confirm lotilaner's safety and anti-tick efficacy in client-owned dogs., Methods: In this assessor-blinded study, dogs were enrolled at 19 clinics in Germany, Hungary and Portugal. Qualifying households with no more than three dogs were randomized in an approximate 2:1 ratio to a lotilaner or fipronil/(S)-methoprene (FSM) (Frontline® Combo Spot-on, Merial) treatment group. One household dog with at least three live attached ticks was the primary dog. Treatments were dispensed Days 0, 28 (± 2) and 56 (± 2) for owner administration to all household dogs. Tick counts were performed on primary dogs Days 7 (± 1), and ±2 days on Days 14, 21, 28, 42, 56, 70 and 84; supplementary dogs were assessed for safety ± 2 days on Days 28, 56 and 84. Efficacy was assessed by comparing mean Day 0 live attached tick counts with subsequent counts., Results: The most frequently retrieved ticks were Ixodes ricinus, Dermacentor reticulatus and Rhipicephalus sanguineus (sensu lato), with Ixodes hexagonus also present. In the lotilaner group (n = 127) geometric mean tick count reductions were at least 98% from the first post-treatment visit (Day 7) through Day 56, when efficacy was 100%. For FSM (n = 68), efficacy remained at least 96% through Day 84, but at no point were all dogs free of live attached ticks. Mean counts in lotilaner-treated dogs were significantly lower than FSM-treated dogs on Days 7, 42, 70 and 84 (P < 0.05). Percent efficacy over all post-enrolment visits was 99.3 and 98.3% for lotilaner and FSM groups, respectively (t (190)  = 2.23, P = 0.0268). Owners successfully administered all treatments, and both products were well-tolerated., Conclusion: Under European field conditions, lotilaner flavoured chewable tablets administered monthly, were > 98% effective in eliminating live ticks from the first post-treatment assessment (Day 7) through Day 56 and maintained 100% of dogs tick-free on Days 70 and 84. Lotilaner was safe, providing superior tick control to FSM administered according to the same schedule.

Background: Lotilaner (Credelio™, Elanco), a novel isoxazoline, is a systemic insecticide and acaricide that is rapidly absorbed following oral administration to dogs and has a half-life of 30 days. As part of a development program, studies were undertaken to investigate lotilaner's initial and sustained efficacy and speed of kill against fleas., Methods: Four studies were conducted to evaluate the onset of lotilaner's speed of flea knockdown at the time of treatment, and to determine the sustained speed of flea kill (SOK) up to 35 days post-treatment. Each study assessed one or two specific time points (4, 6, 8 and 12 h) post-treatment and following weekly re-infestations. In each study, dogs were randomised to a lotilaner or an untreated group based on pre-administration flea counts, and before treatment were infested with adult Ctenocephalides felis. Dogs randomised to a lotilaner group received a single treatment on Day 0, at the minimum recommended dose rate of 20 mg/kg, 30 (± 5) minutes after being fed. Efficacy was calculated using geometric, and arithmetic mean flea counts in treated versus untreated groups., Results: On Day 0, lotilaner efficacy was 89.9% at 4 h, 99.2% at 6 h, 99.9% at 8 h, and 100% at 12 h post-treatment. At each weekly assessment, lotilaner efficacy at 4 h remained at > 97%, at 8 h remained at > 99%, and at 12 h remained at 100% through Day 35. Across all studies, there were no treatment-related adverse events., Conclusion: Lotilaner's rapid flea knockdown immediately following treatment and sustained SOK through 35 days post-treatment offers a new solution for helping to eliminate the health risks that accompany flea infestations on dogs. The consistency of the rapid, sustained flea SOK demonstrated in these studies generates confidence that monthly use of lotilaner in dogs can be valuable in disrupting the flea life cycle in a contaminated environment, and that newly acquired fleas will die quickly, thereby reducing the discomfort of flea bites. The sustained lotilaner SOK also provides confidence that there will be no "end-of-dose" resurgence in flea burdens with the potential accompanying consequence of flares in flea-bite hypersensitivity.

Background: There is a continuing need for novel approaches to tick control in dogs. One such approach lies in the ability of lotilaner (Credelio™), an isoxazoline with a rapid onset of action, to provide sustained efficacy against ticks. Two studies were undertaken to confirm lotilaner's efficacy, at the minimum dose rate of 20 mg/kg, against the three most common tick species in Europe., Methods: In each of two studies, 16 Beagle dogs, at least 6 months old, were ranked and blocked by tick counts from infestations placed approximately 1 week before treatment. Within blocks, dogs were randomized to receive either lotilaner flavoured chewable tablets at as close as possible to, but not less than the minimum dose rate of 20 mg/kg, or to be sham-treated controls. Study 1 assessed lotilaner efficacy against concurrent infestations with 50 (± 6) Rhipicephalus sanguineus and 70 (± 6) Ixodes ricinus; Study 2 infestations were with 50 (± 2) Dermacentor reticulatus. Infestations were performed on Day -2 with counts on Day 2, 48 (± 2) hours post-treatment. Post-treatment infestations were performed on Days 7, 14, 21, 28 and 35, and ticks were counted 48 (±2) hours post-infestations. Efficacy was determined by the percent reduction in mean live tick counts., Results: Control group infestations for each tick species were adequate for assessing lotilaner efficacy at all assessment times. On Day 2 no live ticks were found on any lotilaner-treated dog. For subsequent counts, in Study 1 lotilaner was 100% effective in eliminating live I. ricinus and R. sanguineus on all but two occasions for each tick; on each of those occasions efficacy was sustained at greater than 98.0%. In Study 2, except for a single unattached live tick found on Day 16, efficacy against D. reticulatus was 100% at every post-treatment assessment., Conclusion: The high and sustained efficacy against the three common species of ticks in Europe, R. sanguineus, I. ricinus and D. reticulatus, demonstrates that lotilaner can be a valuable tool in the treatment of canine tick infestations. Lotilaner flavoured chewable tablets were well tolerated and effectiveness was sustained through at least 35 days.

Background: Preclinical studies have shown that the novel isoxazoline, lotilaner (Credelio™, Elanco) administered orally to dogs, produces rapid flea and tick knockdown and sustained speed of kill for at least a month post-treatment with a wide safety margin. A field study was undertaken to validate pre-clinical results., Methods: Dogs were enrolled at 10 veterinary clinics across the United States. Qualifying households containing up to three dogs and one primary dog with at least 10 fleas were randomized 2:1 to receive lotilaner (Credelio™, Elanco) at the recommended minimum dose of 20 mg/kg, or afoxolaner (Nexgard®, Merial), administered per label, to give a minimum dose of 2.5 mg/kg. Treatments were dispensed on Days 0, 30 and 60 for administration by owners; all household dogs received the same treatment as the primary dog. Post-enrollment flea and tick counts were made on primary dogs on Days 30, 60 and 90, and all dogs were assessed for tablet palatability and safety., Results: For efficacy assessments, data were used from 111 lotilaner-treated dogs and 50 afoxolaner-treated dogs; for safety, 197 and 86 dogs, respectively. Percent reductions from baseline in geometric mean flea counts for the lotilaner group were 99.3, 99.9 and 100% on Days 30, 60 and 90, respectively, and for afoxolaner 98.3, 99.8 and 99.8% (P < 0.001, both groups, all days). On Day 90, 100% of lotilaner-treated dogs and 93% of afoxolaner-treated dogs were flea-free. Too few ticks were present to allow assessment. There were no differences in palatability between products (P = 0.2132), with, respectively, 94% and 96% of lotilaner and afoxolaner treatments accepted when offered by hand, in an empty food bowl or with food. Both treatments were well tolerated, alleviating clinical signs of flea allergy dermatitis (FAD) in dogs affected at enrollment., Conclusion: A single owner-administered lotilaner treatment was greater than 99% effective in reducing mean flea counts within 30 days. Three consecutive monthly lotilaner treatments resulted in a 100% reduction in flea infestations, and a substantial reduction in signs of FAD. Lotilaner flavored tablets were readily accepted under field conditions. The absence of treatment-related adverse events confirms the safety of lotilaner in dogs.

Background: Dogs worldwide are at risk of Babesia spp. infections. Preventive efficacy of lotilaner tablets (Credelio™, Elanco) against Babesia canis was evaluated in two studies., Methods: Sixteen dogs in Study 1 and 12 dogs in Study 2, all seronegative and polymerase chain reaction (PCR) negative for B. canis, were randomized to a sham-treated control group or a lotilaner (20-43 mg/kg) treatment group, administered on Day 0 (Study 1: n = 8/group; Study 2: n = 6/group). Dogs were each infested with 50 Dermacentor reticulatus, a percentage of which (Study 1: 8.0-30.0%; Study 2: 12.2%) were infected with B. canis, in Study 1 on Days 2, 7, 14, 21 and 28, and in Study 2 on Day 28. Ticks were removed and counted on Day 30 in Study 1, and Day 34 in Study 2. Blood was collected for Babesia detection via smear, PCR and immunofluorescence assay (IFA) in Study 1 on Day 2, then approximately weekly through Day 56, and in Study 2 at weekly intervals between Days 28 to 49, and on Days 63 and 91. Additional samples were collected from dogs with body temperature > 39.4 °C (measured three times weekly, from Days 7 to 56 in Study 1 and from Days 35 to 56 in Study 2) and positive for B. canis on blood smear. Dogs with confirmed infections were rescue-treated, removed from the study and, in Study 1, replaced., Results: Across both studies B. canis infection of ticks ranged between 8.0-30.0%. In Study 1, all control dogs were positive for B. canis on blood smear and PCR on Day 10 and IFA on Day 21; on Day 21 seven of eight replacement control dogs were B. canis-positive; no replacement dogs were B. canis-positive following tick removal on Day 30. In Study 2, all control dogs were B. canis-positive on Day 56. All lotilaner-treated dogs remained B. canis-negative at all assessments in both studies., Conclusion: Lotilaner efficacy was 100% in preventing establishment of B. canis infection, despite post-treatment challenge with infected ticks on Days 2, 7, 14, 21 and 28.

Background: With the geographical expansion of tick species and increased recognition of pathogens they transmit, there is a requirement for safe and rapidly effective control measures for dogs. Lotilaner, a novel isoxazoline, is rapidly absorbed following administration of a flavored chewable tablet formulation (Credelio™), providing at least 98% efficacy for at least 1 month following assessments at 48 h post-treatment, and following subsequent challenges. A study was conducted to determine the speed with which lotilaner kills ticks., Methods: From 38 dogs, the 32 with the highest Ixodes ricinus counts from a Day -4 infestation were randomized among four groups: two groups were untreated controls, two received lotilaner tablets at a minimum dose rate of 20 mg/kg. Infestations with I. ricinus were performed on Days -2, 7, 14, 21, 28 and 35. Counts were completed 4 and 8 h post-treatment (Day 0), and 8 and 12 h following subsequent infestations. All live ticks were incubated for 24 h following removal from study dogs., Results: At 4 h post-treatment, there was a 69.8% reduction in geometric mean live tick counts in treated dogs compared to controls. After incubation, the reduction increased to 97.2%. At 8 h after treatment, pre- and post-incubation reductions were 99.2 and 100%, respectively. Following post-treatment challenges, post-incubation efficacy through Day 28 at 8 and 12 h was at least 94.3 and 98.0%, respectively, and was 85.7 and 94.2% at 8 and 12 h after the Day 35 challenge. Mean live tick counts in the lotilaner groups were significantly lower than in the control groups at all assessments through Day 35 at 8 (t (7)  ≥ 9, P < 0.0001, Days 0 to 28; t (7)  = 3.54, P ≤ 0.0095, Day 35) and 12 h post-treatment and after subsequent infestations (t (7)  ≥ 10, P < 0.0001, all days). There were no treatment-related adverse events., Conclusion: Lotilaner at a minimum dose rate of 20 mg/kg began to kill ticks on dogs within 4 h of treatment and efficacy was 100% within 8 h. Lotilaner sustained a rapid kill of newly infesting I. ricinus through 35 days. By quickly killing ticks that infest dogs, lotilaner has potential to help limit the transmission of tick-borne pathogens.

Background: Effective control of tick infestations on dogs is important to reduce the risk of transmission of bacterial, viral, and protozoal pathogens. Laboratory studies were initiated to determine the efficacy of lotilaner against common ticks infesting dogs in the United States., Methods: Eight studies investigated the efficacy of lotilaner against ticks. In two studies dogs were infested with both Dermacentor variabilis and Rhipicephalus sanguineus: one additional study was completed for each of these species. Two studies assessed infestations with Amblyomma americanum and two with Ixodes scapularis. In all studies, dogs were ranked and blocked by counts from pre-treatment infestations and randomly allocated, at least eight per group, to be treated orally with lotilaner (minimum dose rate 20 mg/kg), or to be untreated controls. Treatments were administered on Day 0, within 30 min after dogs were fed. In all studies, infestations were performed with 50 adult ticks on Days -2, 7, 14, 21 and 28, and also on Day 35 for R. sanguineus, D. variabilis and I. scapularis. Tick counts were completed 48 h after treatment or after each subsequent challenge. An adequate infestation was defined as at least 25% of the infestation dose recovered from each of at least six control animals at each evaluation. Efficacy calculations for the primary objective were based on geometric means., Results: In all studies, lotilaner was 100% effective against existing infestations. For post-treatment assessments, on only two occasions did efficacy fall below 99%: in one D. variabilis study efficacy was 98.0% on Day 35 and in one I. scapularis study efficacy on Day 16 was 98.4%. Only mild and transient adverse events were observed, and none were considered to be related to treatment., Conclusion: Lotilaner was completely effective against existing infestations with four common species of ticks, D. variabilis, R. sanguineus, A. americanum and I. scapularis, that affect dogs in North America, with at least 4 weeks efficacy of 98.0% or more against subsequent challenge infestations. These results show that lotilaner is a highly effective isoxazoline that offers sustained efficacy against ticks through and beyond the one-month end-of-dose treatment interval.

Background: Lotilaner is a novel isoxazoline developed for oral administration to dogs. In laboratory studies, lotilaner was shown to be safe and to produce a rapid flea and tick knockdown, with a sustained speed of kill for at least a month post-treatment. A study was undertaken to demonstrate the efficacy, safety and palatability of three monthly doses of lotilaner flavoured chewable tablets (Credelio™, Elanco) in controlling fleas under field conditions in Europe., Methods: Dogs were enrolled at 17 veterinary clinics across Germany, Hungary and Portugal. Qualifying households having no more than three dogs and one primary dog with at least five fleas was randomised 2:1 to a lotilaner (minimum dose rate 20 mg/kg) or a topical fipronil group (administered per label). There were 128 and 64 households allocated to the lotilaner and fipronil groups, respectively. Treatments were dispensed to owners on Days 0, 28 and 56; supplementary household dogs received the same treatment as the primary dog. Post-enrollment flea counts and flea allergy dermatitis (FAD) assessments were made on primary dogs on Days 14, 28, 56 and 84. Efficacy calculations were based on geometric mean percent reductions of live flea counts versus pre-treatment counts on Day 0. The safety and palatability of lotilaner tablets were also assessed., Results: Lotilaner efficacy was 99.1, 99.5, 99.9 and 99.8% on Days 14, 28, 56 and 84, respectively. Corresponding reductions for fipronil were 93.4, 91.2, 94.4 and 97.0%. Lotilaner was superior to fipronil at all post-Day 0 assessments (t (186)  ≥ 3.43, P ≤ 0.0007). At every post-treatment assessment, at least 90% of lotilaner-treated dogs were flea-free (98.4% on Day 84); fewer than 90% of fipronil group dogs were flea-free on the same time points. Lotilaner flavoured chewable tablets were palatable, and both products were well tolerated. Lotilaner alleviated or eliminated clinical signs of FAD, including pruritus., Conclusions: Under field conditions in Europe, lotilaner flavoured chewable tablets were greater than 99% effective in eliminating fleas from dogs at the first post-treatment assessment (Day 14). Efficacy was maintained through Day 84, with corresponding improvements in FAD. Lotilaner tablets were palatable and safe and provided superior flea control to fipronil.

Background: Lotilaner (Credelio™) is the newest member of the novel isoxazoline chemical class to be developed to treat canine ectoparasitism. Administered orally, lotilaner is rapidly absorbed with peak blood levels occurring within 2 h post-treatment. A study was undertaken to determine the earliest onset of lotilaner's efficacy against existing flea infestations., Methods: From 72 Beagles, 64 qualifying dogs were ranked in descending order of flea counts from a Day -8 infestation and placed into eight blocks. Within blocks, eight dogs were randomly allocated among eight groups: Groups 1 to 4 were treated orally with lotilaner, at as close as possible to the minimum dose rate of 20 mg/kg within 30 (± 5) minutes after feeding; Groups 5 to 8 were untreated controls. All dogs were infested with 100 ± 5 fleas on Day -2, and whole-body flea counts were completed at 30 min and one, two and 8 h after treatment. Efficacy calculations were based on arithmetic and geometric means if an adequate infestation (at least six of eight untreated dogs with a flea retention of ≥ 50%) was demonstrated in the equivalent control group., Results: Adequate infestations were established in all control groups. At 30 min and 1 h post-treatment, relative to the matching untreated control group, there were no significant reductions in mean flea counts in lotilaner-treated dogs, although moribund fleas were evident at 1 h post-treatment. At 2 h after treatment, compared with the equivalent control group, the geometric mean flea count reduction in the lotilaner group was 64.0% (t (7)  = 2.86, P = 0.0242). At 8 h after treatment, lotilaner efficacy was 99.6%. There were no treatment-related adverse events., Conclusion: This study demonstrates that lotilaner flavored chewable tablets are well tolerated and begin to kill fleas within 2 h of treatment, achieving 99.6% efficacy within 8 h. Lotilaner can therefore be used to quickly alleviate the flea irritation that arises from existing infestations.

Macrocyclic lactone (ML) endectocides are used as chemoprophylaxis for heartworm infection (Dirofilaria immitis) in dogs and cats. Claims of loss of efficacy (LOE) of ML heartworm preventives have become common in some locations in the USA. We directly tested whether resistance to MLs exists in LOE isolates of D. immitis and identified genetic markers that are correlated with, and therefore can predict ML resistance. ML controlled studies showed that LOE strains of D. immitis established infections in dogs despite chemoprophylaxis with oral ivermectin or injectable moxidectin. A whole genome approach was used to search for loci associated with the resistance phenotype. Many loci showed highly significant differences between pools of susceptible and LOE D. immitis. Based on 186 potential marker loci, Sequenom(®) SNP frequency analyses were conducted on 663 individual parasites (adult worms and microfilariae) which were phenotypically characterized as susceptible (SUS), confirmed ML treatment survivors/resistant (RES), or suspected resistant/loss of efficacy (LOE) parasites. There was a subset of SNP loci which appears to be promising markers for predicting ML resistance, including SNPs in some genes that have been associated with ML resistance in other parasites. These data provide unequivocal proof of ML resistance in D. immitis and identify genetic markers that could be used to monitor for ML resistance in heartworms., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Background: Dogs with chronic inflammation, including those with heartworm being managed with macrocyclic lactones and doxycycline (slow kill, SK), may develop immune complexes that block detection of Dirofilaria immitis antigen on commercial tests., Methods: To determine if SK could result in development of false-negative antigen tests, we collected serum samples from dogs that had been diagnosed with heartworm by antigen detection, with or without confirmation by detection of D. immitis microfilariae, placed on monthly macrocyclic lactones and doxycycline, and that later tested negative on an antigen test, and then tested them for antigen of D. immitis before and after treatment to disrupt immune complexes., Results: Serum samples from a total of 15 dogs managed with SK were negative for antigen prior to heating on commercial assay (DiroCHEK, Zoetis) by colorimetric detection and spectrophotometry, but after heat treatment, 8/15 (53.3%) samples converted to positive. Review of the medical records of each dog indicated that, after the heartworm diagnosis, only 7/15 (46.7%) dogs appeared to receive preventive monthly as prescribed, including 3 dogs that had detectable antigen after heating the sample and 4 dogs that did not have detectable antigen after heating. Whole blood was available from 9 dogs; microfilariae of D. immitis were detected in 1 sample., Conclusions: These data suggest that immune complex formation in dogs infected with heartworm and managed with SK can induce false negative antigen test results, misleading veterinarians and owners about the efficacy of this approach. Moreover, compliance with preventive administration appears poor, even after a heartworm diagnosis. The presence of persistent microfilaremia in at least one dog has implications for resistance selection.

Background: Dirofilaria repens is the causative agent of subcutaneous dirofilariosis of dogs, other animals and humans. This nematode is transmitted by mosquitoes of Aedes, Anopheles and Culex genera. In dogs, the parasite may cause subclinical infection or cutaneous signs. Recently, D. repens has emerged and spread in different geographical areas, with an increase of cases in dogs and humans. Chemoprevention in dogs in endemic areas is the most reliable approach for controlling this infection. This paper describes a randomized, blocked and multicentric clinical field study investigating the efficacy of an oral, chewable formulation containing milbemycin oxime/praziquantel (Milbemax®, Novartis Animal Health) in the chemoprevention of subcutaneous dirofilariosis in dogs., Methods: This study was conducted in endemic areas of Italy. A total of 249 dogs, at two sites, negative for D. repens, were allocated into two groups (i.e. Treated -T1 vs Untreated-T2) with a ratio of 1:1, and subjected to clinical visits and blood sampling once monthly until the end of the study. All blood samples were microscopically and genetically examined. Animals belonging to T1 group received a minimum target dose of 0.5 mg/kg bodyweight of milbemycin oxime and 5 mg/kg of praziquantel in commercial tablets (Milbemax®) according body weight once every 4 weeks. Animals of group T2 were not treated with Milbemax® but received, when necessary, specific parasiticide treatments. The study duration was 336 ± 2 days for each dog., Results: A total of 219 dogs completed the study (i.e. 111 in T1 and 108 in T2), while 30 dogs (i.e. 13 in T1, 17 in T2) were withdrawn for a variety of reasons unrelated to administration of Milbemax®. The percentages of animals not showing microfilariae of D. repens were 100% (111 animals) in T1 and 94.7% (108 animals out of 114) in group T2. Milbemax® was shown to be safe in treated dogs., Conclusions: The results of this study confirm that the monthly use of Milbemax® in dogs is effective and safe for the prevention of subcutaneous dirofilariosis in endemic areas.

Background: This survey examines the experience and opinion of veterinarians with canine heartworm (HW; Dirofilaria immitis) infection in non-endemic and endemic areas of Europe., Methods: A questionnaire was distributed by e-mail to veterinary practitioners within non-endemic countries including UK, Germany, and Netherlands,non-endemic regions of France, Spain, Italy and endemic regions of France, Spain and Italy. The main questions were about the HW cases seen in the last 12 months, if the number of cases had changed over the last 5 years and practitioner awareness of the ESCAAP Guidelines on HW. Additional questions examined practitioner perception regarding the risk of HW for pets travelling in endemic areas and the use of preventatives including veterinary perception of pet owner compliance., Results: Overall 584 responses, 389 from non-endemic countries and regions and 195 from endemic regions were obtained. Most of the cases were seen in endemic regions, although in Germany 20% of veterinarians reported cases of HW infection. Overall, 10% of practitioners in non-endemic areasand 12% in endemic areas, respectively, reported an increasing number of cases. The practitioner awareness of ESCCAP guidelines is low. Veterinarians responded that preventative drugs were prescribed to most client dogs in endemic areas and most practitioners rated owner compliance as good or excellent in following the veterinarian's guidance for HW prevention. Overall 63% of veterinarians responded that owners are more or less aware of the HW risk traveling with their dogs in endemic areas. Forty four percent of responders in non-endemic regions considered it somewhat likely to very likely that HW infection will become endemic in their regions., Conclusions: In both non-endemic and endemic countries at least 1 responding practitioner admitted seeing a case of canine HW infection and has shown awareness regarding infection. Ten percent of practitioners stated that the number of cases is increasing. Although the number of owners traveling with their dogs was low, the perception of surveyed veterinarians was that owners were quite aware of the HW risk for their dogs. Several veterinary practitioners believe that HW infection could become endemic in their non-endemic area within the next 10 years.

Intestinal nematodes affecting dogs, i.e. roundworms, hookworms and whipworms, have a relevant health-risk impact for animals and, for most of them, for human beings. Both dogs and humans are typically infected by ingesting infective stages, (i.e. larvated eggs or larvae) present in the environment. The existence of a high rate of soil and grass contamination with infective parasitic elements has been demonstrated worldwide in leisure, recreational, public and urban areas, i.e. parks, green areas, bicycle paths, city squares, playgrounds, sandpits, beaches. This review discusses the epidemiological and sanitary importance of faecal pollution with canine intestinal parasites in urban environments and the integrated approaches useful to minimize the risk of infection in different settings.

Veterinarians in Ontario and Quebec, Canada, typically prescribe monthly heartworm prophylactic and anthelmintic medications for use during the warm months of the year. In many patients, the use of dewormers is discontinued during the winter because of the perception that intestinal parasite infections and shedding of nematode eggs are unlikely when the weather is cold and the ground is frozen or covered with snow. This study examined fecal samples obtained from 96 shelter dogs and cats during the winter in Ontario and Quebec. Intestinal parasites were identified in 34% of submitted samples. These findings support the recommendation that veterinarians should advise pet owners to continue administration of broad-spectrum parasiticides to companion animals during the winter months.