Explore the vast range of titles available.

Background The cat flea ( Ctenocephalides felis), a parasite commonly found on both dogs and cats, is a competent vector for several zoonotic pathogens, including Dipylidium caninum (tapeworms), Bartonella henselae (responsible for cat scratch disease) and Rickettsia felis (responsible for flea-borne spotted fever). Veterinarians recommend that both cats and dogs be routinely treated with medications to prevent flea infestation. Nevertheless, surveys suggest that nearly one third of pet owners do not routinely administer appropriate preventatives. Methods A mathematical model based on weighted averaging over time is developed to predict outdoor flea activity from weather conditions for the contiguous United States. This ‘nowcast’ model can be updated in real time as weather conditions change and serves as an important tool for educating pet owners about the risks of flea-borne disease. We validate our model using Google Trends data for searches for the term ‘fleas.’ This Google Trends data serve as a proxy for true flea activity, as validating the model by collecting fleas over the entire USA is prohibitively costly and time-consuming. Results The average correlation ( r ) between the nowcast outdoor flea activity predictions and the Google Trends data was moderate: 0.65, 0.70, 0.66, 0.71 and 0.63 for 2016, 2017, 2018, 2019 and 2020, respectively. However, there was substantial regional variation in performance, with the average correlation in the East South Atlantic states being 0.81 while the average correlation in the Mountain states was only 0.45. The nowcast predictions displayed strong seasonal and geographic patterns, with predicted activity generally being highest in the summer months. Conclusions The nowcast model is a valuable tool by which to educate pet owners regarding the risk of fleas and flea-borne disease and the need to routinely administer flea preventatives. While it is ideal for domestic cats and dogs to on flea preventatives year-round, many pets remain vulnerable to flea infestation. Alerting pet owners to the local increased risk of flea activity during certain times of the year may motivate them to administer appropriate routine preventives. Graphical Abstract

Ctenocephalides felis is a common ectoparasite of dogs and cats and can transmit a variety of pathogens including Bartonella and Rickettsia species. These bacteria, along with the known endosymbiont Wolbachia, are well-documented members of the C. felis microbiome, but species-level information is limited. Additionally, little is known about the variation in the C. felis microbiome in fleas from different sources and when different sequencing methods are applied to the same samples. This study aimed to characterize the flea microbiome using both short-read (V3/V4) and long-read (full-length) 16S rRNA gene sequencing, determine whether long-read sequencing improves species-level identification especially in known pathogenic genera, and evaluate differences in microbial composition between fleas collected from cats, dogs, and environmental traps. Fleas were collected from cats, dogs, and traps in flea-infested homes in Florida, pooled by source, and sequenced using short- (V3/V4) and long-read (full-length) 16S rRNA gene sequencing. Microbial prevalence and abundance were compared across sequencing approaches. Community composition was evaluated for differences between sources and houses. Candidate members of the flea microbiome were identified based on a combination of prevalence, abundance, and statistical signatures of potential contaminant origin. For Rickettsia and Bartonella, species-level taxonomic assignments were refined using a phylogenetic approach. Wolbachia, Rickettsia, and Bartonella were the most prevalent and abundant taxa. Spiroplasma was identified as a fourth core member of the flea microbiome. Long-read sequencing enabled better, but not perfect, species-level classification of Bartonella and Rickettsia compared to short-read sequencing. Important relationships between specific ASVs and flea sources were identified, for example fleas from cats harbored higher abundances of B. clarridgeiae and B. henselae than fleas from traps.

Background Flea infestations remain a major issue in veterinary medicine. Highly effective flea control for dogs and cats remains the foundation for eliminating infestations from homes and improving skin conditions associated with flea-feeding. Methods Homes with pet cats were screened by flea-history questionnaire. Qualifying homes were subselected into “high” (≥ 5 fleas on ≥ 1 cat, and ≥ 5 fleas collected in environmental flea traps over a 16–24 h period), “low” (< 5 fleas on all cats, < 5 in traps), and “no” homes (no evidence of fleas on cats or traps). All cats and dogs in a household were treated with a lotilaner oral tablet (Credelio ® CAT and Credelio ® , respectively) in weeks 0, 4, and 8. On-animal and trap counts were performed for: “high” at weeks 0, 1, 2, 4, 6, 8, and 11–12; “low” at week 0 and at approximately 2-week intervals through week 11–12; and “no” only at week 0. During each visit, one owner completed a pruritus assessment (PVAS) and a veterinary dermatologist assessed dermatologic lesions using the feline allergic dermatitis (SCORFAD) scale. Results A total of 46 homes met inclusion criteria and completed the study: 19 “high” (35 cats); 17 “low” (27); and 10 “no” (14). By week 1, relative to pretreatment, there was a 99.3% reduction in flea counts on “high” cats, with 31 of 34 cats (91.2%) flea-free. By week 11–12, flea counts across all study cats and traps were zero. Prior to the first treatment, mean PVAS scores were: “high” 6.6; “low” 5.5; and “no” 1.9. By week 1 there was a significant decrease in mean PVAS score of cats from “high” homes to 2.9 ( P  < 0.0001), and mean week 11–12 scores were 0.5 and 0.8 for “high” and “low” homes, respectively. For SCORFAD, by week 11–12, relative to week 0, there was a significant decline in mean scores of cats from both “high” (8.0 to 1.7) ( P  < 0.0001) and “low” homes (3.3 to 0.9) ( P  < 0.0001). Conclusions Lotilaner was 100% efficacious in eliminating flea infestations from animals and their homes. The monthly lotilaner treatments of cats and dogs in flea-infested homes resulted in clinical resolution of pruritus and dermatologic lesions. Graphical abstract

Background Companion animal endoparasites play a substantial role in both veterinary medicine and public health. Updated epidemiological studies are necessary to identify trends in occurrence and distribution of these parasites, and their associated risk factors. This study aimed to assess the occurrence of canine endoparasites  retrospectively, using fecal flotation  test data available through participating academic veterinary parasitology diagnostic laboratories across the United States of America (USA). Methods Canine fecal flotation records from ten veterinary diagnostic laboratories located in nine states in the USA acquired from January 1, 2018, to December 31, 2018, were included. Results A total of 4692 fecal flotation test results were obtained, with a majority comprised of client-owned dogs (3262; 69.52%), followed by research dogs (375; 8.00%), and shelter dogs (122; 2.60%). Samples from 976 (20.80%) dogs were positive for at least one parasite, and co-infections of two or more parasites were found in 3.82% (179/4692) of the samples. The five most commonly detected parasites were: Giardia  sp., (8.33%; 391/4692), Ancylostomatidae (5.63%; 264/4692), Cystoisospora spp. (4.35%; 204/4692), Toxocara canis (2.49%;117/4692), and Trichuris vulpis (2.43%; 114/4692). Various other internal parasites, including gastrointestinal and respiratory nematodes, cestodes, trematodes, and protozoans were detected in less than 1% of samples. Conclusions These data illustrate the importance of parasite prevention, routine fecal screening, and treatment of pet dogs. Additionally, pet owners should be educated about general parasite prevalence, prevention, and anthelmintic treatment regimens to reduce the risks of environmental contamination and zoonotic transmission. Graphical Abstract

The effect of Bartonella henselae on the microbiome of its vector, Ctenocephalides felis (the cat flea) is largely unknown, as the majority of C. felis microbiome studies have utilized wild-caught pooled fleas. We surveyed the microbiome of laboratory-origin C. felis fed on B. henselae-infected cats for 24 h or 9 days to identify changes to microbiome diversity and microbe prevalence compared to unfed fleas, and fleas fed on uninfected cats. Utilizing Next Generation Sequencing (NGS) on the Illumina platform, we documented an increase in microbial diversity in C. felis fed on Bartonella-infected cats for 24 h. These changes returned to baseline (unfed fleas or fleas fed on uninfected cats) after 9 days on the host. Increased diversity in the C. felis microbiome when fed on B. henselae-infected cats may be related to the mammalian, flea, or endosymbiont response. Poor B. henselae acquisition was documented with only one of four infected flea pools having B. henselae detected by NGS. We hypothesize this is due to the use of adult fleas, flea genetic variation, or lack of co-feeding with B. henselae-infected fleas. Future studies are necessary to fully characterize the effect of endosymbionts and C. felis diversity on B. henselae acquisition.

Abstract Background Canine acaricides with rapid onset and sustained activity can reduce pathogen transmission risk and enhance pet owner experience. This randomized, complete block design, investigator-masked study compared the speed of kill of Amblyomma americanum provided by three monthly-use isoxazoline-containing products. Methods Eight randomized beagles per group were treated (day 0), per label, with sarolaner (combined with moxidectin and pyrantel, Simparica Trio™), afoxolaner (NexGard™), or lotilaner (Credelio™), or remained untreated. Infestations with 50 adult A. americanum were conducted on days − 7, − 2, 21, and 28, and tick counts were performed on day − 5 (for blocking), and at 4, 8, 12, 24, 48, and 72 h following treatment and subsequent infestations. Efficacy calculations were based on geometric mean live tick counts. A linear mixed model was used for between-group comparisons. Results On day 0, only lotilaner significantly reduced an A. americanum infestation by 12 h (43.3%; P  = 0.002). Efficacy of lotilaner and afoxolaner at 24 h post-treatment was 95.3% and 97.6%, respectively, both significantly different from sarolaner (74%) ( P  = 0.002, P  < 0.001, respectively). On day 21, at 12 h postinfestation, lotilaner efficacy (59.6%) was significantly different from sarolaner (0.0%) ( P  < 0.001) and afoxolaner (6.3%) ( P  < 0.001). At 24 h, lotilaner efficacy (97.4%) was significantly different ( P  < 0.001) from sarolaner and afoxolaner (13.6% and 14.9%, respectively). On day 28, at 12 h postinfestation, lotilaner efficacy (47.8%) was significantly different from sarolaner (17.1%) ( P  = 0.020) and afoxolaner (9.0%) ( P  = 0.006). At 24 h, lotilaner efficacy (92.3%) was significantly different from sarolaner 4.9% ( P  < 0.001) and afoxolaner (0.0%) ( P  < 0.001). Speed of kill for sarolaner and afoxolaner, but not lotilaner, significantly declined over the study period. Following reinfestation on day 28, neither sarolaner nor afoxolaner reached 90% efficacy by 48 h. By 72 h, sarolaner efficacy was 97.4% and afoxolaner efficacy was 86.3%. Only lotilaner achieved ≥ 90% efficacy by 24 h post-treatment and 24 h postinfestation on days 21 and 28. Time to ≥ 90% efficacy following new infestations consistently occurred 24–48 h earlier for lotilaner compared with sarolaner or afoxolaner. Conclusions Credelio (lotilaner) has a more rapid onset of acaricidal activity against A. americanum than Simparica Trio (sarolaner-moxidectin-pyrantel) and NexGard (afoxolaner). Only lotilaner’s speed of tick kill is sustained throughout the dosing period. Graphical Abstract

Introduction Alpha‐gal syndrome (AGS) is characterized by delayed hypersensitivity to non‐primate mammalian meat in people having specific immunoglobulin E (sIgE) to the oligosaccharide galactose‐alpha‐1,3‐galactose. AGS has been linked to tick bites from Amblyomma americanum (Aa) in the U.S. A small animal model of meat allergy is needed to study the mechanism of alpha‐gal sensitization, the effector phase leading to delayed allergic responses and potential therapeutics to treat AGS. Methods Eight‐ to ten‐weeks old mice with a targeted inactivation of alpha‐1,3‐galactosyltransferase (AGKO) were injected intradermally with 50 μg of Aa tick salivary gland extract (TSGE) on days 0, 7, 21, 28, 42, and 49. Total IgE and alpha‐gal sIgE were quantitated on Day 56 by enzyme‐linked immunosorbent assay. Mice were challenged orally with 400 mg of cooked pork kidney homogenate or pork fat. Reaction severity was assessed by measuring a drop in core body temperature and scoring allergic signs. Results Compared to control animals, mice treated with TSGE had 190‐fold higher total IgE on Day 56 (0.60 ± 0.12 ng/ml vs. 113.2 ± 24.77 ng/ml; p < 0.001). Alpha‐gal sIgE was also produced in AGKO mice following TSGE sensitization (undetected vs. 158.4 ± 72.43 pg/ml). Further, sensitized mice displayed moderate clinical allergic signs along with a drop in core body temperature of ≥2°C as an objective measure of a systemic allergic reaction. Interestingly, female mice had higher total IgE responses to TSGE treatment but male mice had larger declines in mean body temperature. Conclusion TSGE‐sensitized AGKO mice generate sIgE to alpha‐gal and demonstrate characteristic allergic responses to pork fat and pork kidney. In keeping with the AGS responses documented in humans, mice reacted more rapidly to organ meat than to high fat pork challenge. This mouse model establishes the central role of tick bites in the development of AGS and provides a small animal model to mechanistically study mammalian meat allergy. Alpha‐gal syndrome (AGS) is characterized by delayed hypersensitivity to non‐primate mammalian meat in people having specific IgE (sIgE) to the oligosaccharide galactose‐alpha‐1,3‐galactose and has been linked to tick bites from Amblyomma americanum (Aa) in the U.S. We demonstrate that intradermal injection of Aa tick salivary gland extract (TSGE) in alpha‐gal knockout (AGKO) mice induce alpha‐gal sIgE production and mice displayed moderate clinical allergic signs along with a drop in core body temperature as an objective measure of a systemic allergic reaction. Further, this model recapitulates several aspects of red meat allergy seen in the humans and will be used to mechanistically study this novel food allergy and model therapeutic approaches to treat this disease.

Background To manage tick infestations and reduce tick-borne pathogen transmission risk to dogs, compliant administration of a fast-acting ectoparasiticide is necessary. Isoxazoline-containing ectoparasiticide products provide systemic whole-body coverage; however, differences in tick kill have been observed between products and these differences may be more pronounced when controlling common dose-limiting tick species such as Amblyomma americanum . Methods Dogs were ranked by tick carrying capacity, randomly allocated to one of three treatment groups, and administered Bravecto® Chews (minimum 25 mg/kg fluralaner), Simparica TRIO® (minimum 1.2 mg/kg sarolaner, 24 µg/kg moxidectin, 5 mg/kg pyrantel), or no treatment. Dogs were infested with approximately 50 unfed adult (25 female, 25 male) A. americanum on days −2, 21, 28, and 35. Live tick counts were performed at 8, 12, 24, 48, and 72 h post-treatment (day 0) and post-infestation on days 21, 28, and 35. At each tick count timepoint, product efficacy was determined by comparing geometric mean live tick counts for each product-treated group to the untreated group and a linear mixed model was used for between-group comparisons. Results Compared with untreated dogs, significant control of existing A. americanum infestations began by 8 h post-treatment (81.6%) and reached 98.0% control by 12-h for Bravecto®-treated dogs. In comparison, significant control for Simparica TRIO®-treated dogs began by 24 h post-treatment (97.7%). When reinfested on day 21, A. americanum infestations were controlled more quickly for Bravecto® compared with Simparica TRIO®-treated dogs at 12 h (efficacy 95.3% versus 25.5%, P <  0.001) and 24 h (efficacy 99.7% versus 70.9%, P  < 0.001) post-infestation. Similarly, when reinfested on day 28, faster A. americanum control occurred for Bravecto® compared with Simparica TRIO®-treated dogs at 12 h (efficacy 87.9% versus 18.3%, P  < 0.001) and at 24 h (99.2% versus 59.3%, P  < 0.001) post-infestation. Finally, when reinfested on day 35, time to ≥ 90% efficacy was achieved by 48 h for Bravecto®-treated dogs compared with 72 h post-infestation for Simparica TRIO®-treated dogs. Both products performed within label indications and no treatment-related adverse reactions occurred during the study. Conclusions Amblyomma americanum infestations are controlled more quickly immediately upon treatment and at 21, 28, and 35 days post-treatment for Bravecto® compared with Simparica TRIO®-treated dogs. Graphical Abstract

Background Compliant ectoparasiticide product use is a comprehensive way to control ticks and reduce the risk of tick-borne pathogen transmission to dogs. Because the systemically acting isoxazoline ectoparasiticides require tick attachment for drug delivery, fast speed of kill is essential to minimize tick-borne pathogen transmission risk. Methods Dogs of satisfactory tick-carrying capacity were randomly allocated to treatment groups and administered, per label instructions, Bravecto ® Chews (minimum 25 mg/kg fluralaner), Simparica TRIO ® (minimum 1.2 mg/kg sarolaner, 24 µg/kg moxidectin, 5 mg/kg pyrantel), or no treatment. Dogs were infested with approximately 50 unfed adult (35 female, 15 male) Ixodes scapularis on Day -2, 21 and 28. Live tick counts were performed at 4, 8, 12 and 24 h post-treatment (Day 0) and post-infestation on Day 21 and 28. Tick control efficacy was determined by comparing live tick means for each product-treated group to the untreated control group and each other at all time points using a linear mixed model. The percent of dogs free of live ticks was analyzed using the Fisher’s exact test for treatment group comparison. Results The untreated control group maintained adequate tick infestations throughout the study. Using geometric means, an existing I. scapularis infestation was controlled by 99.7% and 93.0% 12 h post-treatment and by 100% and 99.5% 24 h post-treatment, for Bravecto ® and Simparica TRIO ® -treated dogs, respectively. Ixodes scapularis infestations were controlled more quickly for Bravecto ® - compared to Simparica TRIO ® -treated dogs on Day 21 at 8 h (efficacy 74.0% vs. 0.0%, p  = 0.003) and 12 h (efficacy 99.2% vs. 39.4%, p  < 0.001) post-infestation and Day 28 at 8 h (efficacy 92.2% vs. 0.0%, p  < 0.001) and 12 h (efficacy 99.6% vs. 27.7%, p  < 0.001) post-infestation. On Day 28 post-treatment, the efficacy of Bravecto ® and Simparica TRIO ® to control a new I. scapularis infestation was 100% and 96.6%, respectively, by 24 h post-infestation. Of product-treated dogs, 100% of Bravecto ® -treated dogs were free of live ticks by 24 h post-treatment or post-infestation. No treatment-related adverse reactions occurred during the study. Conclusions Ixodes scapularis infestations are controlled more quickly 21 and 28 days post-treatment for dogs administered a single dose of Bravecto ® compared to dogs administered a single dose of Simparica TRIO ® . Graphical Abstract

Background Canine test results generated by veterinarians throughout Canada from 2013–2014 were evaluated to assess the geographical distribution of canine infection with Borrelia burgdorferi , Dirofilaria immitis , Ehrlichia spp., and Anaplasma spp. Methods The percent positive test results of 115,636 SNAP® 4Dx® Plus tests from dogs tested were collated by province and municipality to determine the distribution of these vector-borne infections in Canada. Results A total of 2,844/115,636 (2.5%) dogs tested positive for antibody to B. burgdorferi . In contrast, positive test results for D. immitis antigen and antibodies to Ehrlichia spp. and Anaplasma spp. were low, with less than 0.5% of dogs testing positive for any one of these three agents nationwide. Provincial seroprevalence for antibodies to B. burgdorferi ranged from 0.5% (Saskatchewan)–15.7% (Nova Scotia); the areas of highest percent positive test results were in proximity to regions in the USA considered endemic for Lyme borreliosis, including Nova Scotia (15.7%) and Eastern Ontario (5.1%). These high endemic foci, which had significantly higher percent positive test results than the rest of the nation ( P  < 0.0001), were surrounded by areas of moderate to low seroprevalence in New Brunswick (3.7%), Quebec (2.8%), and the rest of Ontario (0.9%), as well as northward and westward through Manitoba (2.4%) and Saskatchewan (0.5%). Insufficient results were available from the westernmost provinces, including Alberta and British Columbia, to allow analysis. Conclusion Increased surveillance of these vector-borne disease agents, especially B. burgdorferi , is important as climate, vector range, and habitat continues to change throughout Canada. Using dogs as sentinels for these pathogens can aid in recognition of the public and veterinary health threat that each pose.