Use of a modified SCORFAD scale to define localised reaction patterns associated with a flea burden in cats.

BACKGROUND: The SCORing Feline Allergic Dermatitis scale (SCORFAD) is a validated dermatological scale assessing reaction patterns associated with allergic dermatitis in cats. While no pathognomonic reaction pattern is recognised with flea allergy dermatitis (FAD), miliary dermatitis is more common. HYPOTHESIS/OBJECTIVE: This study aimed to document regional cutaneous reaction patterns of cats with fleas using a modified SCORFAD (mSCORFAD). ANIMALS: In total, 142 owned cats from West Central Florida enrolled over three study periods. To be included, each cat and household environment had five or more fleas on Day (D)0. MATERIALS AND METHODS: Cats were examined on D0, D7, D14, D21, D28, D44, D56 and D80. On D0 they were treated with an isoxazoline and treatment continued through the study. Ten body regions were assessed using mSCORFAD to give a regional score for each of four reaction patterns. These were compared using the Wilcoxon rank sum test. RESULTS: At D80 there was an 80% reduction in total mSCORFAD representing clinical response to ectoparasite control only. The most commonly affected region was the ventral abdomen with a mean mSCORFAD score of 1.8 (95% confidence interval = 1.5-2.1) compared with other body regions (p < 0.01). The most common reaction patterns were self-induced alopecia on the ventral abdomen and miliary dermatitis in the cervical region (p < 0.0001). CONCLUSIONS AND CLINICAL RELEVANCE: The mSCORFAD suggests that self-induced alopecia on the ventral abdomen and miliary dermatitis in the cervical region is more strongly associated with a flea burden in cats.

A nowcast model to predict outdoor flea activity in real time for the contiguous United States.

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.

Differential burdens of blacklegged ticks (Ixodes scapularis) on sympatric rodent hosts.

In the United States, there has been a steady increase in diagnosed cases of tick-borne diseases in people, most notably Lyme disease. The pathogen that causes Lyme disease, Borrelia burgdorferi, is transmitted by the blacklegged tick (Ixodes scapularis). Several small mammals are considered key reservoirs of this pathogen and are frequently-used hosts by blacklegged ticks. However, limited studies have evaluated between-species host use by ticks. This study compared I. scapularis burdens and tick-associated pathogen presence in wild-caught Clethrionomys gapperi (southern red-backed voles) and Peromyscus spp. (white-footed mice) in forested areas where the habitat of both species overlapped. Rodent trapping data collected over two summers showed a significant difference in the average tick burden between species. Adult Peromyscus spp. had an overall mean of 4.03 ticks per capture, while adult C. gapperi had a mean of 0.47 ticks per capture. There was a significant association between B. burgdorferi infection and host species with more Peromyscus spp. positive samples than C. gapperi (65.8% and 10.2%, respectively). This work confirms significant differences in tick-host use and pathogen presence between sympatric rodent species. It is critical to understand tick-host interactions and tick distributions to develop effective and efficient tick control methods.

Comparison of the initial and residual speed of Ixodes scapularis kill on dogs treated with a single dose of Bravecto® Chew (25 mg/kg fluralaner) or Simparica TRIO® (1.2 mg/kg sarolaner, 24 µg/kg moxidectin, 5 mg/kg pyrantel).

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®.

Identification and treatment of Strongyloides cebus in captive ring-tailed lemurs (Lemur catta) in the midwestern United States.

Strongyloides spp. are parasitic enteric nematodes that infect a variety of hosts. While the Strongyloides spp. that affect humans, apes, and Old World primates have been previously identified, this genus has not been as fully investigated in prosimian species such as ring-tailed lemurs (Lemur catta). A high burden (4+) of larvated eggs and larvae were identified in the fecal samples of two captive ring-tailed lemurs during routine intake examination at a zoo in the midwestern United States. Conventional PCR targeting the 18S RNA gene of nematodes was used identified the parasite as Strongyloides cebus. The lemurs were initially treated with 0.2 mg/kg ivermectin orally twice, two weeks apart. Repeat fecal sampling showed persistent, but decreased eggs and larvae from 4+ to 3+. Ivermectin treatment was repeated with the addition of fenbendazole at 50 mg/kg orally once daily for 3 days. No parasite stages were seen on fecal samples one week and six weeks after the last ivermectin indicating successful clearance of the infection.

Feeding on a Bartonella henselae Infected Host Triggers Temporary Changes in the Ctenocephalides felis Microbiome.

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.

Mitochondrial Genomes of the American Dog Tick (Dermacentor variabilis) Isolated from Horses in the Midwestern United States.

Here, we report two complete and three partial mitochondrial genome sequences of Dermacentor variabilis specimens collected from horses in the United States. The complete genomes are 14,837 bp long and contain 13 protein-coding genes, 2 rRNA genes, and 22 tRNA genes. The sequences have been deposited under GenBank accession numbers ON052120 to ON052124.

Analysis of the complete mitochondrial genomes of Dermacentor albipictus suggests a species complex.

Dermacentor albipictus is a one-host tick broadly distributed across North America. There are two easily recognizable color variants - ornate and inornate/brown - that have been taxonomically synonymized. Based on mt-cox1 and mt-16S data, there is also evidence for two genetic lineages which do not match the color variants. We present for the first time the complete mitochondrial genomes of the two color variants of D. albipictus including representatives of each lineage. The AT-rich genomes are 14,822 bp - 14,865 bp in length and contain 13 protein coding genes, 2 ribosomal RNA genes and 22 transfer RNA genes, arranged in the conserved type 3 metastriate mitochondrial genome order. The overall differences were 10.66% between the mitochondrial genomes of D. albipictus ornate variant lineage 1 and lineage 2, 10.51% between lineage 1 and inornate/brown variant and 5.87% between lineage 2 and inornate/brown variant. The inornate/brown variant did not form a separate lineage and all inornate isolates were found to belong to lineage 2. Ornate variant isolates occurred in both lineage 1 and 2. The high divergence of the mitochondrial genome suggests that D. albipictus may represent a species complex. Other barcoding genes that may help capture the genetic differences between color and lineage variants include nad1, nad2, nad5, cox1 and atp8 loci. The mtDNA data generated in this study are available in GenBank (Accession numbers: OM678457 - OM678459 and ON032564 - ON032573) for future studies on tick taxonomy, phylogenetics and molecular epidemiology.

Seroprevalence of Borrelia burgdorferi in Shelter Dogs in Los Angeles County.

The primary aim of this study was to establish the seroprevalence of Borrelia burgdorferi in dogs in Los Angeles County by testing shelter and client owned dogs with 2-tier ELISA testing. A secondary goal was to create a pilot study for evaluation of all Borrelia positive dogs for dermatologic signs of infection. This is the first study to look at the seroprevalence of Borrelia burgdorferi in dogs in Los Angeles County. We hypothesized that the prevalence is higher than previously predicted (0.5%-1%). 422 shelter and client owned dogs were tested for Borrelia burgdorferi with an ELISA cageside test. Seropositive animals were to have additional blood sent to a reference laboratory for further ELISA testing and examined for dermatologic manifestations of Borrelia burgdorferi. No dogs tested positive for Borrelia burgdorferi in this study population, however 3 dogs tested positive for Ehrlichia and 1 for Anaplasma, 2 other tick-borne pathogens uncommon in southern California. This is the first study in Los Angeles County to employ active surveillance regarding an important zoonotic disease. The findings prove that results from these types of studies may differ from those of predictions and passive surveillance. Dogs are sentinels for disease in people and focus should be placed on monitoring antibody levels in canine patients. This study carried out in an endemic area may prove more valuable in assessing cutaneous manifestations of Borrelia burgdorferi and provide a foundation for future hypothesis driven studies.

Using Proteomic Approaches to Unravel the Response of Ctenocephalides felis felis to Blood Feeding and Infection With Bartonella henselae.

Among the Ctenocephalides felis felis-borne pathogens, Bartonella henselae, the main aetiological agent of cat scratch disease (CSD), is of increasing comparative biomedical importance. Despite the importance of B. henselae as an emergent pathogen, prevention of the diseases caused by this agent in cats, dogs and humans mostly relies on the use of ectoparasiticides. A vaccine targeting both flea fitness and pathogen competence is an attractive choice requiring the identification of flea proteins/metabolites with a dual effect. Even though recent developments in vector and pathogen -omics have advanced the understanding of the genetic factors and molecular pathways involved at the tick-pathogen interface, leading to discovery of candidate protective antigens, only a few studies have focused on the interaction between fleas and flea-borne pathogens. Taking into account the period of time needed for B. henselae replication in flea digestive tract, the present study investigated flea-differentially abundant proteins (FDAP) in unfed fleas, fleas fed on uninfected cats, and fleas fed on B. henselae-infected cats at 24 hours and 9 days after the beginning of blood feeding. Proteomics approaches were designed and implemented to interrogate differentially expressed proteins, so as to gain a better understanding of proteomic changes associated with the initial B. henselae transmission period (24 hour timepoint) and a subsequent time point 9 days after blood ingestion and flea infection. As a result, serine proteases, ribosomal proteins, proteasome subunit α-type, juvenile hormone epoxide hydrolase 1, vitellogenin C, allantoinase, phosphoenolpyruvate carboxykinase, succinic semialdehyde dehydrogenase, glycinamide ribotide transformylase, secreted salivary acid phosphatase had high abundance in response of C. felis blood feeding and/or infection by B. henselae. In contrast, high abundance of serpin-1, arginine kinase, ribosomal proteins, peritrophin-like protein, and FS-H/FSI antigen family member 3 was strongly associated with unfed cat fleas. Findings from this study provide insights into proteomic response of cat fleas to B. henselae infected and uninfected blood meal, as well as C. felis response to invading B. henselae over an infection time course, thus helping understand the complex interactions between cat fleas and B. henselae at protein levels.

Retrospective study of canine endoparasites diagnosed by fecal flotation methods analyzed across veterinary parasitology diagnostic laboratories, United States, 2018.

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.

Early onset of pre-lethal effects of lotilaner (Credelio®) on Amblyomma americanum ticks on experimentally infested dogs.

BACKGROUND: The speed with which acaricides paralyze and kill ticks is relevant to impeding pathogen transmission. The objective of this study was to assess early-onset lotilaner effects on the motility and weights of Amblyomma americanum ticks collected from treated dogs. METHODS: Twelve healthy dogs were randomized between two groups to receive either lotilaner (Credelio®) on Day 0 or to be sham treated. On Day 7, 25 male and 25 female A. americanum were placed under bandages, two on each flank of each dog. After 30 or 45 min, all unattached ticks were removed and T = 0 was set. At T = 2, 4, 8 and 24 h post attachment, 5 attached ticks removed from each bandage on each dog were weighed, assessed by blinded observers for righting ability and movement recorded. RESULTS: After the infestation period significantly fewer treated than control dogs had 20 ticks attached (50.0% versus 91.7%, P = 0.0015). At 24 h post attachment, mean weights of ticks from treated dogs (males 1.69 mg; females 2.72) were significantly less than ticks from controls (males 2.66 mg; females 4.67) (Pmale = 0.0002; Pfemale < 0.0001). Mean tick weights from the treated group were significantly lower at 24 h than at earlier time points (Pmale < 0.0307; Pfemale = 0.0021). At 4 and 8 h, significantly fewer ticks from treated (14.3%, 0.0%, respectively) than from control dogs could right (73.3%, 70.0%) (P4h < 0.0001; P8h = 0.0024) (at 24 h, all ticks from treated dogs were dead), and distance moved was significantly less at all time points (P2h = 0.0413; P4h, P8h < 0.0001). Mean and maximum velocity of ticks from treated dogs were significantly lower, relative to controls, at 4 and 8 h (P ≤ 0.0001). Within the treated group, collected ticks had significantly lower mean and maximum velocities at 4 and 8 h compared to 2 h (Pmean < 0.0042; Pmax < 0.0194). CONCLUSION: The observed changes indicate that lotilaner may disrupt tick attachment. In ticks that attached, a progressive impairment of neuromuscular processes began within 2 h. Those irreversible changes could substantially reduce the risk of pathogen transmission from tick to host.

Tick salivary gland extract induces alpha-gal syndrome in alpha-gal deficient mice.

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.

Evaluation of a topical sarolaner-selamectin combination to control flea populations on naturally infested cats in private residences in West Central Florida.

Historic data show that home flea infestations can be managed by treating all animals on the premises with a highly effective flea control product. The use of effective products has also been shown to reduce pruritus and minimize dermatologic lesions in both cats and dogs. Therefore, an in-home study was conducted in West Central Florida USA to evaluate the efficacy of a topically applied selamectin-sarolaner formulation to control fleas in naturally infested cats over a 12-week period. Thirty-seven cats in 21 households were treated once monthly with the selamectin-sarolaner topical solution. In the topical fluralaner treatment (positive control) group, forty-three cats in 20 households were treated once on day 0. A combined total of thirty dogs in both groups were treated once monthly with oral sarolaner. Fleas on cats were counted by flea combing, fleas on dogs were counted using visual area counts and fleas in the indoor premises were assessed using intermittent-light flea traps. Blinded-assessments of feline dermatologic lesions (modified-SCORFAD) were conducted monthly by a boarded-dermatologist and pruritus severity was evaluated by pet owners. Three consecutive monthly treatments of selamectin-sarolaner reduced flea populations on cats by 96.3 % within 7 days and by 100% from week 6 to the end of the 12-week study. The topical application of fluralaner reduced flea populations by 98.1 % within 7 days and efficacy reached 100% by week 12. At the end of the study, fleas were completely eradicated (from cats, dogs and homes) in every home regardless of treatment group. Owner reported cat pruritus was reduced by > 87 % in both treatment groups by week 12. Significant improvements in dermatologic lesion scores (> 81 %) were achieved by both products by the end of the study. Monthly applications of topical selamectin-sarolaner or topical fluralaner to cats living in the heavy flea challenge environment of West Central Florida USA were effective in eradicating flea infestations, reducing pruritus and improving dermatologic lesions.

Evaluation of oral fluralaner (Bravecto®) for efficacy against nymphs of Amblyomma americanum and Rhipicephalus sanguineus (sensu lato).

BACKGROUND: Amblyomma americanum and Rhipicephalus sanguineus (sensu lato) nymphs commonly feed on and transmit pathogens to dogs (Canis familiaris). Control of immature and adult tick life stages is necessary to fully protect animals. We evaluated efficacy of oral fluralaner (Bravecto®) against induced infestations with A. americanum and R. sanguineus (s.l.) nymphs on dogs in two experiments. METHODS: In each experiment, 10 dogs were administered oral fluralaner chewable tablets one time on Day 0 at a targeted minimum dose of 25 mg/kg body weight and 10 dogs remained non-treated controls. Dogs were infested with two groups of 50 A. americanum nymphs and two groups of 50 R. sanguineus (s.l.) nymphs on Days -1, 6, 28, 56 and 84. At 48 h and 72 h post-infestation, nymphs were collected from dogs, assessed as live or dead, and enumerated into categories defining attachment and engorgement status. Fluralaner efficacy was determined in separate analyses against all live nymphs and against live-fed nymphs, i.e. live nymphs that were attached to dogs at the time of collection and/or were engorged. Fluralaner was considered effective when mean numbers of live ticks were reduced in fluralaner-treated dogs by ≥ 90%. RESULTS: Fluralaner efficacy against all live and live-fed A. americanum nymphs in the first experiment was > 94% on all collection days. Efficacy against all live R. sanguineus (s.l.) nymphs in the first experiment was > 96% on all collection days  excluding the 48 h counts for infestations on Days 28 (83.7%), 56 (82.9%) and 84 (86.7%); efficacy against live-fed R. sanguineus (s.l.) nymphs was > 95% on all 48 h/72 h count days. Fluralaner efficacy against all live A. americanum nymphs in the second experiment was > 93% on all collection days for 8 weeks excluding the 48 h count for infestation on Day 56 (87.8%); efficacy against live-fed A. americanum nymphs was > 91% on all count days for 8 weeks. Efficacy against all live R. sanguineus (s.l.) nymphs in the  second experiment was > 91% on all 72 h collection days  except for infestations on Days 28 (76.8%) and 56 (86.3%); efficacy against live-fed R. sanguineus (s.l.) nymphs was 100% on all 72 h count days. CONCLUSIONS: A single administration of oral fluralaner to dogs is effective against A. americanum and R. sanguineus (s.l.) nymphs for up to 12 weeks.

Trypanosoma cruzi infection in a zoo-housed red panda in Kansas.

A 9-y-old, zoo-housed, male red panda (Ailurus fulgens) became progressively lethargic and inappetent over a 1-wk period. Physical examination was unremarkable. A complete blood count showed mild normocytic, normochromic, non-regenerative anemia with the presence of trypomastigote organisms, consistent with a Trypanosoma sp. The organism was confirmed later as Trypanosoma cruzi lineage TcI via PCR and genome sequencing. The panda was initially treated supportively; however, its clinical status within 24 h from presentation deteriorated, and euthanasia was elected. Autopsy showed severe systemic T. cruzi infection with the presence of amastigotes in the heart, brain, peripheral nerves, skeletal muscles, tongue, liver, and testes. We used genome sequencing and serology in identifying the agent.

In-home assessment of flea control and dermatologic lesions in dogs provided by lotilaner (Credelio®) and spinosad (Comfortis®) in west central Florida.

Post-launch field investigations of recently-approved flea control products establish an efficacy baseline and in subsequent years can detect any efficacy decline suggestive of emerging resistance. As part of a continuing program of yearly assessment of flea control products in west central Florida, this study, using client-owned dogs, investigated the efficacy of lotilaner and spinosad in controlling fleas and in alleviating dermatologic signs likely associated with flea infestations. Forty-four qualifying households were randomized to either a lotilaner (Credelio®) (minimum dose rate 20 mg/kg) or a spinosad (Comfortis®) (30 mg/kg) group, with 33 and 36 dogs in each group, respectively. On Days 0 and 28 (±2) all dogs in each household were treated with the allocated product according to label directions, and all household cats received spinetoram (Cheristin®). On Day 0 and at weekly intervals through Day 56 (±2), on-animal and premises flea burdens were enumerated, a veterinary dermatologist scored integumental changes using canine atopic dermatitis extent and severity index (CADESI)-4 and flea allergy dermatitis (FAD) scales, and owners scored pruritus using the validated canine pruritus severity scale (CPSS). At study entry geometric mean flea counts were 33.2 and 29.9 in the lotilaner and spinosad groups, respectively. For both groups, reductions in flea counts were > 99% at the first post-treatment assessment (Week 1), and 100% from Week 6 through the final assessment (Week 8) when all study dogs were flea-free. For both groups, at each timepoint, flea counts on dogs and in traps were significantly reduced compared to the initial assessment (p < 0.001), as were improvements in median CADESI-4, FAD and CPSS scores (p ≤ 0.001). At Week 4, the geometric mean flea count on dogs in the lotilaner group (0.1) was significantly lower than that of dogs in the spinosad group (0.6) (p = 0.027), significantly fewer dogs in the lotilaner group were found to have fleas (p = 0.034), and mean owner-rated pruritus scores were significantly lower (p = 0.025). Under field conditions favoring heavy flea challenge, two consecutive monthly treatments of dogs with either lotilaner or spinosad produced a 100% reduction in canine flea infestations and dramatic improvements in dermatologic lesions and pruritus, based on scoring by a veterinary dermatologist and by dog owners. Household flea burdens were driven to extinction in all but one home in each treatment group.

In-home assessment of flea control and dermatologic lesions in dogs provided by lotilaner (Credelio®) and spinosad (Comfortis®) in west central Florida.

Post-launch field investigations of recently-approved flea control products establish an efficacy baseline and in subsequent years can detect any efficacy decline suggestive of emerging resistance. As part of a continuing program of yearly assessment of flea control products in west central Florida, this study, using client-owned dogs, investigated the efficacy of lotilaner and spinosad in controlling fleas and in alleviating dermatologic signs likely associated with flea infestations. Forty-four qualifying households were randomized to either a lotilaner (Credelio®) (minimum dose rate 20 mg/kg) or a spinosad (Comfortis®) (30 mg/kg) group, with 33 and 36 dogs in each group, respectively. On Days 0 and 28 (±2) all dogs in each household were treated with the allocated product according to label directions, and all household cats received spinetoram (Cheristin®). On Day 0 and at weekly intervals through Day 56 (±2), on-animal and premises flea burdens were enumerated, a veterinary dermatologist scored integumental changes using canine atopic dermatitis extent and severity index (CADESI)-4 and flea allergy dermatitis (FAD) scales, and owners scored pruritus using the validated canine pruritus severity scale (CPSS). At study entry geometric mean flea counts were 33.2 and 29.9 in the lotilaner and spinosad groups, respectively. For both groups, reductions in flea counts were > 99% at the first post-treatment assessment (Week 1), and 100% from Week 6 through the final assessment (Week 8) when all study dogs were flea-free. For both groups, at each timepoint, flea counts on dogs and in traps were significantly reduced compared to the initial assessment (p < 0.001), as were improvements in median CADESI-4, FAD and CPSS scores (p ≤ 0.001). At Week 4, the geometric mean flea count on dogs in the lotilaner group (0.1) was significantly lower than that of dogs in the spinosad group (0.6) (p = 0.027), significantly fewer dogs in the lotilaner group were found to have fleas (p = 0.034), and mean owner-rated pruritus scores were significantly lower (p = 0.025). Under field conditions favoring heavy flea challenge, two consecutive monthly treatments of dogs with either lotilaner or spinosad produced a 100% reduction in canine flea infestations and dramatic improvements in dermatologic lesions and pruritus, based on scoring by a veterinary dermatologist and by dog owners. Household flea burdens were driven to extinction in all but one home in each treatment group.

Efficacy of a topical formulation of selamectin plus sarolaner against induced infestations of Amblyomma americanum on cats and prevention of Cytauxzoon felis transmission.

Cytauxzoonosis, caused by infection with Cytauxzoon felis, is the most severe tick-borne disease of cats. The purpose of our study was to determine the efficacy of selamectin (6.0 mg/kg) plus sarolaner (1.0 mg/kg) formulated in combination (Revolution® Plus / Stronghold® Plus, Zoetis) applied topically once a month on cats for three months against induced infestations of Amblyomma americanum adults and to evaluate the effectiveness of the product in preventing the transmission of C. felis. This study was conducted in two phases. Sixteen cats were dosed with selamectin/sarolaner or a placebo (vehicle control) on Days 0, 28, and 56. In phase 1, each cat was infested with 50 (±5) unfed adult A. americanum on Day 4 and tick counts were conducted on Day 6 (48 h post infestation) and Day 7 (72 h post infestation) to evaluate acaricidal efficacy. In phase 2, to confirm acaricidal efficacy and evaluate prevention of C. felis transmission, each cat was infested on Day 60 with 50 (±5) adult A. americanum acquisition fed as nymphs on two C. felis-infected donor cats. Tick counts were conducted on Day 62 (48 h post infestation) and Day 63 (72 h post infestation). Blood samples were collected on Days -9, 60, 70, 76, and 90 and tested for infection with C. felis. Placebo cats were adequately infested on all count days, with least squares (geometric) mean live tick counts ranging from 34.0 (28.8) to 46.1 (46.0). Treatment reduced the least squares (geometric) mean counts compared to placebo by 27.1 (32.1)% and 90.4 (96.8)% on Days 6 and 7, respectively. The corresponding percent reductions were 56.4 (60.6)% and 94.7 (97.3)% on Days 62 and 63, respectively. Least squares mean counts were significantly lower in the treated group compared with the placebo group on all count days (P ≤ 0.0286). All cats were negative for C. felis by PCR prior to study start. In phase 2, seven cats in the control group and no cats in the selamectin/sarolaner group became infected with C. felis (P = 0.0017). Topical treatment with selamectin/sarolaner was >90% effective in reducing A. americanum tick counts 72 h after infestation and prevented the transmission of C. felis from infected ticks following the third of three monthly treatments. Revolution® Plus / Stronghold® Plus offers an option for the control of A. americanum infestations on cats and for preventing the transmission of C. felis to cats.

Ticks from cats in the United States: Patterns of infestation and infection with pathogens.

Ticks are an important but under recognized parasitic threat to cats in many areas of the United States. To characterize the species and stages of ticks most commonly recovered from cats and determine the prevalence of disease agents in the ticks, we conducted a survey of ticks removed from cats at veterinary practices in 18 states from April 2016-June 2017. A total of 796 ticks were submitted from 332 cats from 41 different veterinary practices. A single tick was submitted from the majority of cats, with a mean infestation intensity of 2.4 (range 1-46). The most common tick was Ixodes scapularis, accounting for 422/796 (53.0%) ticks submitted, followed by Amblyomma americanum (224/796; 28.1%) and Dermacentor variabilis (131/796; 16.5%); a few I. pacificus, I. banksi, D. occidentalis, A. maculatum, Rhipicephalus sanguineus, and Otobius megnini were also submitted. A majority of ticks were adults (593/796; 74.5%); females predominated in all adult tick submissions including I. scapularis (277/327; 84.7% female), A. americanum (66/128; 51.6% female), and D. variabilis (75/126; 59.5% female). Immature ticks included 186 nymphs and 17 larvae and were primarily I. scapularis and A. americanum. Adult I. scapularis were most reported to be attached to the dorsal head and neck; A. americanum to the abdomen and perianal region; and D. variabilis to the back and ear. Ticks were collected in every month; the largest number of submissions were in May and June (42.5% of ticks) and October and November (35.9% of ticks). Adults of I. scapularis were most commonly submitted October through December, A. americanum March through June, and D. variabilis May through July. Cats with ticks were predominantly male (58.8%) and altered (76.2%), and most reportedly spent >30% of time outdoors, although 64/294 (21.8%) for which lifestyle estimates were provided were reported to live primarily (≤30% of time outside; n = 54) or entirely (100%; n = 10) indoors. Assay of ticks removed from cats revealed I. scapularis were infected with Borrelia burgdorferi (25.7%) and Anaplasma phagocytophilum (4.4%); A. americanum were infected with Ehrlichia chaffeensis (1.3%); and D. variabilis were infected with spotted fever group Rickettsia spp. (3.1%). No ticks in this study tested positive for Cytauxzoon felis. Pet cats, including those that live primarily indoors, are at risk of tick infestation, potentially exposed to tick-borne disease agents, and would benefit from routine tick control.