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Mason V Reichard - One of the best experts on this subject based on the ideXlab platform.
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efficacy of a topical formulation of selamectin plus sarolaner against induced infestations of amblyomma americanum on cats and prevention of Cytauxzoon Felis transmission
Veterinary Parasitology, 2019Co-Authors: Mason V Reichard, Jennifer E. Thomas, Kelly E. Allen, Jady J Rugg, Annie W Barrett, Jill K Murray, Brian H Herrin, Rachel A Beam, Vickie L King, Adriano F VattaAbstract:Abstract 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.
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Transmission of Cytauxzoon Felis to domestic cats by Amblyomma americanum nymphs.
Parasites & vectors, 2019Co-Authors: Kelly E. Allen, Jennifer E. Thomas, Megan L. Wohltjen, Mason V ReichardAbstract:Successful Cytauxzoon Felis transmission studies have occurred using Amblyomma americanum adults acquisition-fed as nymphs on an experimentally infected domestic cat or Dermacentor variabilis adults fed as nymphs on a splenectomized bobcat. Here, we evaluated A. americanum and D. variabilis nymphs acquisition-fed as larvae on a C. Felis-infected carrier domestic cat for competence to transmit the protozoan parasite as nymphs to naive, healthy domestic cats. Amblyomma americanum and D. variabilis larvae were applied to a chronically infected, parasitemic C. Felis donor cat (Felis catus) and allowed to feed to repletion. Engorged larvae were collected and held through ecdysis. Three cats were each infested with 66 A. americanum or 66 D. variabilis emerged nymphs. Cytauxzoon Felis infections in principal cats were determined by clinical signs and detection of circulating parasite by blood smear and PCR evaluation. Clinical signs of Cytauxzoonosis were observed in cats infested with A. americanum nymphs beginning 12–15 days post-infestation (dpi). The same cats were PCR positive on 12–14 dpi; piroplasms were evident in blood smears at 16 dpi, and macrophage schizonts were observed in stained spleen impression smears in two animals at necropsy. Cats infested with acquisition-fed D. variabilis nymphs remained clinically normal and did not develop detectable parasitemia over the course of the study as determined by blood smear and PCR. Cytauxzoon Felis was successfully transmitted to domestic cats by A. americanum nymphs acquisition-fed as larvae on the donor cat. However, we were not able to transmit C. Felis to healthy domestic cats with D. variabilis nymphs that were simultaneously acquisition-fed on the same donor cat. Results from this study suggest that larval and nymphal A. americanum likely play important roles in natural transmission cycles of C. Felis.
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Transmission of Cytauxzoon Felis to domestic cats by Amblyomma americanum nymphs
BMC, 2019Co-Authors: Kelly E. Allen, Jennifer E. Thomas, Megan L. Wohltjen, Mason V ReichardAbstract:Abstract Background Successful Cytauxzoon Felis transmission studies have occurred using Amblyomma americanum adults acquisition-fed as nymphs on an experimentally infected domestic cat or Dermacentor variabilis adults fed as nymphs on a splenectomized bobcat. Here, we evaluated A. americanum and D. variabilis nymphs acquisition-fed as larvae on a C. Felis-infected carrier domestic cat for competence to transmit the protozoan parasite as nymphs to naïve, healthy domestic cats. Methods Amblyomma americanum and D. variabilis larvae were applied to a chronically infected, parasitemic C. Felis donor cat (Felis catus) and allowed to feed to repletion. Engorged larvae were collected and held through ecdysis. Three cats were each infested with 66 A. americanum or 66 D. variabilis emerged nymphs. Cytauxzoon Felis infections in principal cats were determined by clinical signs and detection of circulating parasite by blood smear and PCR evaluation. Results Clinical signs of Cytauxzoonosis were observed in cats infested with A. americanum nymphs beginning 12–15 days post-infestation (dpi). The same cats were PCR positive on 12–14 dpi; piroplasms were evident in blood smears at 16 dpi, and macrophage schizonts were observed in stained spleen impression smears in two animals at necropsy. Cats infested with acquisition-fed D. variabilis nymphs remained clinically normal and did not develop detectable parasitemia over the course of the study as determined by blood smear and PCR. Conclusions Cytauxzoon Felis was successfully transmitted to domestic cats by A. americanum nymphs acquisition-fed as larvae on the donor cat. However, we were not able to transmit C. Felis to healthy domestic cats with D. variabilis nymphs that were simultaneously acquisition-fed on the same donor cat. Results from this study suggest that larval and nymphal A. americanum likely play important roles in natural transmission cycles of C. Felis
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Minimum transmission time of Cytauxzoon Felis by Amblyomma americanum to domestic cats in relation to duration of infestation, and investigation of ingestion of infected ticks as a potential route of transmission.
Journal of feline medicine and surgery, 2017Co-Authors: Jennifer E. Thomas, Cameon M. Ohmes, Mark E. Payton, Joseph A. Hostetler, Mason V ReichardAbstract:Objectives The objectives of the present study were to determine the duration of infestation by Amblyomma americanum necessary for transmission of Cytauxzoon Felis to domestic cats and to determine if ingestion of C Felis-infected A americanum by cats is a route of transmission. Methods Forty-nine cats were assigned to one of seven groups, with seven cats per group. Cats were infested with A americanum adults, acquisition fed as nymphs on a Cytauxzoonosis survivor cat, for 12 h (group 1), 18 h (group 2), 24 h (group 3), 36 h (group 4), 48 h (group 5) and to repletion (group 7; control). Cats in group 6 were fed C Felis-infected ticks. Thumb counts were performed at the end of the duration of infestation for groups 1-5 and at 48 h for the control group. For group 6, 50 live C Felis-infected adult A americanum were mixed with food and fed to each of the cats. Transmission of C Felis was determined by examining blood of cats by DNA extraction followed by PCR. Results Of 50 ticks placed on each cat (groups 1-5 and 7), the arithmetic mean attachment ± SEM ranged from 46.9 ± 1.9 in group 3 to 49.3 ± 0.3 in group 1. In group 6, the average number ± SEM of ticks ingested was 46.5 ± 2.3. One cat in group 5 that had been infested for 48 h became infected with C Felis. None of the cats in group 6 (ingestion) became infected with C Felis. Six of 7 (85.7%) cats in group 7, the control group, became infected with C Felis. Conclusions and relevance Our results indicate that transmission of C Felis to domestic cats can happen as quickly as >36 h but ⩽48 h of exposure to A americanum infected with C Felis and that ingestion of C Felis-infected A americanum is not a likely route of transmission.
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prevalence of Cytauxzoon Felis infection in healthy cats from enzootic areas in arkansas missouri and oklahoma
Parasites & Vectors, 2015Co-Authors: Theresa E Rizzi, Mason V Reichard, Leah A Cohn, Adam J Birkenheuer, Jared D Taylor, James H MeinkothAbstract:Background Infection with Cytauxzoon Felis in domestic cats can cause fever, lethargy, depression, inappetence, icterus, and often death. With a high mortality rate, Cytauxzoonosis was historically considered a fatal disease. Within the last 15 years, cats with or without treatment have been recognized as chronically infected survivors of C. Felis infection. Our objective was to determine the prevalence of C. Felis in healthy domestic cats from Arkansas, Missouri, and Oklahoma.
Adam J Birkenheuer - One of the best experts on this subject based on the ideXlab platform.
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second illness due to subsequent Cytauxzoon Felis infection in a domestic cat
Journal of Feline Medicine and Surgery Open Reports, 2020Co-Authors: Leah A Cohn, Dan Shaw, Catherine Shoemake, Adam J BirkenheuerAbstract:Case summaryA castrated male domestic shorthair cat from a wooded area in Missouri had recovered from typical severe Cytauxzoonosis at 4 years of age, after intensive in-hospital supportive care an...
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Genetic conservation of Cytauxzoon Felis antigens and mRNA expression in the schizont life-stage.
Veterinary parasitology, 2018Co-Authors: Daven B. Khana, Adam J Birkenheuer, Megan E. Schreeg, David S. Peterson, James B. Stanton, Jaime L. TarigoAbstract:Abstract Cytauxzoonosis is a highly fatal disease of domestic cats caused by the apicomplexan protozoan Cytauxzoon Felis, which is most closely related to Theileria spp. The growing prevalence, high morbidity and mortality, and treatment cost of Cytauxzoonosis emphasize the need for vaccine development. Traditional approaches for vaccine development, however, have been hindered by the inability to culture C. Felis in vitro. Recent availability of the annotated C. Felis genome combined with genome-based vaccine design and protein microarray immunoscreening allowed for high-throughput identification of C. Felis antigens that could serve as vaccine candidates. This study assessed the suitability of three of these vaccine candidates (cf30, cf63, cf58) in addition to a previously reported vaccine candidate (cf76) based on two criteria: genetic conservation among diverse C. Felis geographic isolates and expression in tissues containing the C. Felis schizont life stage, which has been previously associated with the development of a protective immune response. A comparison of seventeen C. Felis isolates across seven states demonstrated high sequence identity (99–100%) for cf30, cf63, and cf58, similar to the degree of conservation previously reported for cf76. RNAscope® in situ hybridization using acutely infected feline splenic tissue revealed robust levels of all transcripts in the schizont life stage of the parasite. These data support the suitability of these three antigens for further investigation as vaccine candidates against Cytauxzoonosis.
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Mitochondrial Genome Sequences and Structures Aid in the Resolution of Piroplasmida phylogeny
PloS one, 2016Co-Authors: Megan E. Schreeg, Leah A Cohn, Henry S. Marr, Michael G. Levy, Jaime L. Tarigo, David Mck. Bird, Elizabeth H. Scholl, Brian M. Wiegmann, Adam J BirkenheuerAbstract:The taxonomy of the order Piroplasmida, which includes a number of clinically and economically relevant organisms, is a hotly debated topic amongst parasitologists. Three genera (Babesia, Theileria, and Cytauxzoon) are recognized based on parasite life cycle characteristics, but molecular phylogenetic analyses of 18S sequences have suggested the presence of five or more distinct Piroplasmida lineages. Despite these important advancements, a few studies have been unable to define the taxonomic relationships of some organisms (e.g. C. Felis and T. equi) with respect to other Piroplasmida. Additional evidence from mitochondrial genome sequences and synteny should aid in the inference of Piroplasmida phylogeny and resolution of taxonomic uncertainties. In this study, we have amplified, sequenced, and annotated seven previously uncharacterized mitochondrial genomes (Babesia canis, Babesia vogeli, Babesia rossi, Babesia sp. Coco, Babesia conradae, Babesia microti-like sp., and Cytauxzoon Felis) and identified additional ribosomal fragments in ten previously characterized mitochondrial genomes. Phylogenetic analysis of concatenated mitochondrial and 18S sequences as well as cox1 amino acid sequence identified five distinct Piroplasmida groups, each of which possesses a unique mitochondrial genome structure. Specifically, our results confirm the existence of four previously identified clades (B. microti group, Babesia sensu stricto, Theileria equi, and a Babesia sensu latu group that includes B. conradae) while supporting the integration of Theileria and Cytauxzoon species into a single fifth taxon. Although known biological characteristics of Piroplasmida corroborate the proposed phylogeny, more investigation into parasite life cycles is warranted to further understand the evolution of the Piroplasmida. Our results provide an evolutionary framework for comparative biology of these important animal and human pathogens and help focus renewed efforts toward understanding the phylogenetic relationships within the group.
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prevalence of Cytauxzoon Felis infection in healthy cats from enzootic areas in arkansas missouri and oklahoma
Parasites & Vectors, 2015Co-Authors: Theresa E Rizzi, Mason V Reichard, Leah A Cohn, Adam J Birkenheuer, Jared D Taylor, James H MeinkothAbstract:Background Infection with Cytauxzoon Felis in domestic cats can cause fever, lethargy, depression, inappetence, icterus, and often death. With a high mortality rate, Cytauxzoonosis was historically considered a fatal disease. Within the last 15 years, cats with or without treatment have been recognized as chronically infected survivors of C. Felis infection. Our objective was to determine the prevalence of C. Felis in healthy domestic cats from Arkansas, Missouri, and Oklahoma.
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domestic cats with Cytauxzoonosis atovaquone and azithromycin therapy in implications for b cytochrome of Cytauxzoon Felis
2014Co-Authors: Michael G. Levy, Adam J Birkenheuer, Megan E. Schreeg, Henry S. Marr, Jaime L. TarigoAbstract:(1, 2).Without treatment, Cytauxzoonosis is fatal in up to 97% ofdomestic cats (3). Recent advances in treatment combiningatovaquone and azithromycin (A&A) have reduced the mortal-ity rate to 40% (3). Azithromycin targets the mitochondrialribosomes of the parasite, while atovaquone targets protozoalcytochrome
Jose Vicente Lopezbao - One of the best experts on this subject based on the ideXlab platform.
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feline leukemia virus and other pathogens as important threats to the survival of the critically endangered iberian lynx lynx pardinus
PLOS ONE, 2009Co-Authors: Marina L Meli, Valentino Cattori, Fernando Martinez, Guillermo Lopez, Astrid Vargas, Miguel A Simon, Irene Zorrilla, Alvaro Munoz, Francisco Palomares, Jose Vicente LopezbaoAbstract:Background: the Iberian lynx (Lynx pardinus) is considered the most endangered felid species in the world. In order to save this species, the Spanish authorities implemented a captive breeding program recruiting lynxes from the wild. In this context, a retrospective survey on prevalence of selected feline pathogens in free-ranging lynxes was initiated. Methodology/ Principal Findings: we systematically analyzed the prevalence and importance of seven viral, one protozoan (Cytauxzoon Felis), and several bacterial (e.g., hemotropic mycoplasma) infections in 77 of approximately 200 remaining free-ranging Iberian lynxes of the Donana and Sierra Morena areas, in Southern Spain, between 2003 and 2007. With the exception of feline immunodeficiency virus (FIV), evidence of infection by all tested feline pathogens was found in Iberian lynxes. Fourteen lynxes were feline leukemia virus (FeLV) provirus-positive; eleven of these were antigenemic (FeLV p27 positive). All 14 animals tested negative for other viral infections. During a six-month period in 2007, six of the provirus-positive antigenemic lynxes died. Infection with FeLV but not with other infectious agents was associated with mortality (p<0.001). Sequencing of the FeLV surface glycoprotein gene revealed a common origin for ten of the eleven samples. The ten sequences were closely related to FeLV-A/61E, originally isolated from cats in the USA. Endogenous FeLV sequences were not detected. Conclusions/Significance: It was concluded that the FeLV infection most likely originated from domestic cats invading the lynx's habitats. Data available regarding the time frame, co-infections, and outcome of FeLV-infections suggest that, in contrast to the domestic cat, the FeLV strain affecting the lynxes in 2007 is highly virulent to this species. Our data argue strongly for vaccination of lynxes and domestic cats in and around lynx's habitats in order to prevent further spread of the virus as well as reduction the domestic cat population if the lynx population is to be maintained.
James H Meinkoth - One of the best experts on this subject based on the ideXlab platform.
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prevalence of Cytauxzoon Felis infection in healthy cats from enzootic areas in arkansas missouri and oklahoma
Parasites & Vectors, 2015Co-Authors: Theresa E Rizzi, Mason V Reichard, Leah A Cohn, Adam J Birkenheuer, Jared D Taylor, James H MeinkothAbstract:Background Infection with Cytauxzoon Felis in domestic cats can cause fever, lethargy, depression, inappetence, icterus, and often death. With a high mortality rate, Cytauxzoonosis was historically considered a fatal disease. Within the last 15 years, cats with or without treatment have been recognized as chronically infected survivors of C. Felis infection. Our objective was to determine the prevalence of C. Felis in healthy domestic cats from Arkansas, Missouri, and Oklahoma.
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efficacy of an imidacloprid 10 flumethrin 4 5 collar seresto bayer for preventing the transmission of Cytauxzoon Felis to domestic cats by amblyomma americanum
Parasitology Research, 2013Co-Authors: Mason V Reichard, Kara L Raetzel, Robert G. Arther, Jeffrey A Hostetler, James H MeinkothAbstract:: Infection of Cytauxzoon Felis in domestic cats produces a severe disease characterised by fever, lethargy, inappetence, anorexia, depression, dehydration, icterus and often death. Transmission of C. Felis to cats is dependent on being fed upon by infected Amblyomma americanum (lone star ticks). The purpose of the present study was to determine if application of a 10 % imidacloprid/4.5 % flumethrin collar (Seresto®, Bayer) on cats prevents transmission of C. Felis by repelling ticks. Twenty cats were randomised to either a treated (n = 10) or non-treated control group (n = 10) based on their susceptibility to ticks. Cats of high, medium and low tick susceptibility were represented in both groups. Treated cats were fitted with 10 % imidacloprid/4.5 % flumethrin collars on study day 0 and both groups were then infested with C. Felis-infected A. americanum on study day 30. Tick thumb counts were performed at 24 and 48 hours post infestation. Transmission of C. Felis was determined by examining blood of cats by DNA extraction followed by PCR amplification with piroplasm-specific primers. Ticks did not attach to any of the 10 % imidacloprid/4.5 % flumethrin- treated cats. However, ticks attached and fed on all the non-treated control cats. The geometric mean number of ticks attached to the non-treated control cats at 24 and 48 hours was 15.3 and 14.2, respectively. Cytauxzoon Felis was transmitted to 9 of 10 (90 %) non-treated control cats; C. Felis was not transmitted to any of the treated cats. Transmission of C. Felis to the non-treated cats was first detected between 8 and 16 days post infestation. Our results indicate that application of the 10 % imidacloprid/4.5 % flumethrin collar to cats prevented ticks from attaching, feeding and transmitting C. Felis.
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Confirmation of Amblyomma americanum (Acari: Ixodidae) as a Vector for Cytauxzoon Felis (Piroplasmorida: Theileriidae) to Domestic Cats
Journal of medical entomology, 2010Co-Authors: Mason V Reichard, James H Meinkoth, Timothy A. Snider, Amy C Edwards, Katrina R. Meinkoth, Rebecca E. Heinz, Susan E. LittleAbstract:Amblyomma americanum was confirmed as a competent vector in the transmission of Cytauxzoon Felis to domestic cats. Infection with C. Felis was produced and replicated in four domestic felines by the bite of A. americanum adults that were acquisition fed as nymphs on a domestic cat that survived Cytauxzoonosis. Numerous attempts to transmit C. Felis with Dermacentor variabilis at the same time were not successful. All cats upon which infected A. americanum were transmission fed exhibited disease typical of Cytauxzoonosis, and the eitiologic agent's presence was confirmed. Clinical signs including fever, inappetence, depression, and lethargy were observed beginning 13 d postinfestation. Pale mucus membranes, splenomegaly, icterus, and dyspnea were also observed during the course of the disease. Rectal temperatures of the C. Felis-infected principal cats fluctuated from high to subnormal before returning to the normal range. Clinical signs of Cytauxzoonsis improved by 24 d postinfestation in all but one cat, with survivors remaining parasitemic and subclinically infected with C. Felis. Unengorged A. americanum and D. variabilis were collected from wild habitats to determine the minimum infection rate of C. Felis in ticks from an enzootic area. Infection of C. Felis was found only in wild-collected A. americanum. The minimum infection rate of C. Felis in A. americanum was 0.5% (one of 178) in males, 0.8% (three of 393) in nymphs, and 1.5% (three of 197) in females. We found no wild-collected D. variabilis infected with C. Felis. Our results confirm that A. americanum is a primary vector of C. Felis.
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Transmission of Cytauxzoon Felis to a domestic cat by Amblyomma americanum.
Veterinary parasitology, 2008Co-Authors: Mason V Reichard, Katherine M. Kocan, James H Meinkoth, Timothy A. Snider, Amy C Edwards, Edmour F. BlouinAbstract:Cytauxzoon Felis was transmitted to a domestic cat by Amblyomma americanum. The infection was produced by the bite of A. americanum adults that were acquisition fed as nymphs on a domestic cat that naturally survived infection of C. Felis. Fever, inappetence, depression, and lethargy were first noted 11 days post-infestation (dpi). Pale mucus membranes, splenomegaly, icterus, and dyspnea were also observed during the course of the disease. The body temperature of the experimentally infected C. Felis cat was subnormal from 16 dpi until 24 dpi when it returned to within normal limits. All clinical signs of Cytauxzoonsis began to resolve by 23 dpi when the cat became subclinically infected with C. Felis. The cat developed a marked, regenerative anemia beginning by 13 dpi and reached a nadir at 20 dpi before recovering. A moderate neutrophilia and marked lymphocytosis also developed between 18 and 26 dpi. Schizonts of C. Felis were observed in spleen aspirates of the infected cat at 15 dpi. DNA of C. Felis was amplified by real-time PCR starting 17 dpi and piroplasms of C. Felis were first noted by light microscopy 18 dpi. Dermacentor variabilis, Ixodes scapularis, and Rhipicephalus sanguineus were also tested in a similar manner at the same time but did not transmit C. Felis. Prior to the present study, only D. variabilis had been shown experimentally to transmit infection of C. Felis. This is the first report of C. Felis being transmitted by A. americanum. The transmission of C. Felis infection from one domestic cat to another indicates that domestic cats subclinically infected with C. Felis may be a reservoir of infection for naive domestic cats.
Kelly E. Allen - One of the best experts on this subject based on the ideXlab platform.
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efficacy of a topical formulation of selamectin plus sarolaner against induced infestations of amblyomma americanum on cats and prevention of Cytauxzoon Felis transmission
Veterinary Parasitology, 2019Co-Authors: Mason V Reichard, Jennifer E. Thomas, Kelly E. Allen, Jady J Rugg, Annie W Barrett, Jill K Murray, Brian H Herrin, Rachel A Beam, Vickie L King, Adriano F VattaAbstract:Abstract 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.
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Transmission of Cytauxzoon Felis to domestic cats by Amblyomma americanum nymphs.
Parasites & vectors, 2019Co-Authors: Kelly E. Allen, Jennifer E. Thomas, Megan L. Wohltjen, Mason V ReichardAbstract:Successful Cytauxzoon Felis transmission studies have occurred using Amblyomma americanum adults acquisition-fed as nymphs on an experimentally infected domestic cat or Dermacentor variabilis adults fed as nymphs on a splenectomized bobcat. Here, we evaluated A. americanum and D. variabilis nymphs acquisition-fed as larvae on a C. Felis-infected carrier domestic cat for competence to transmit the protozoan parasite as nymphs to naive, healthy domestic cats. Amblyomma americanum and D. variabilis larvae were applied to a chronically infected, parasitemic C. Felis donor cat (Felis catus) and allowed to feed to repletion. Engorged larvae were collected and held through ecdysis. Three cats were each infested with 66 A. americanum or 66 D. variabilis emerged nymphs. Cytauxzoon Felis infections in principal cats were determined by clinical signs and detection of circulating parasite by blood smear and PCR evaluation. Clinical signs of Cytauxzoonosis were observed in cats infested with A. americanum nymphs beginning 12–15 days post-infestation (dpi). The same cats were PCR positive on 12–14 dpi; piroplasms were evident in blood smears at 16 dpi, and macrophage schizonts were observed in stained spleen impression smears in two animals at necropsy. Cats infested with acquisition-fed D. variabilis nymphs remained clinically normal and did not develop detectable parasitemia over the course of the study as determined by blood smear and PCR. Cytauxzoon Felis was successfully transmitted to domestic cats by A. americanum nymphs acquisition-fed as larvae on the donor cat. However, we were not able to transmit C. Felis to healthy domestic cats with D. variabilis nymphs that were simultaneously acquisition-fed on the same donor cat. Results from this study suggest that larval and nymphal A. americanum likely play important roles in natural transmission cycles of C. Felis.
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Transmission of Cytauxzoon Felis to domestic cats by Amblyomma americanum nymphs
BMC, 2019Co-Authors: Kelly E. Allen, Jennifer E. Thomas, Megan L. Wohltjen, Mason V ReichardAbstract:Abstract Background Successful Cytauxzoon Felis transmission studies have occurred using Amblyomma americanum adults acquisition-fed as nymphs on an experimentally infected domestic cat or Dermacentor variabilis adults fed as nymphs on a splenectomized bobcat. Here, we evaluated A. americanum and D. variabilis nymphs acquisition-fed as larvae on a C. Felis-infected carrier domestic cat for competence to transmit the protozoan parasite as nymphs to naïve, healthy domestic cats. Methods Amblyomma americanum and D. variabilis larvae were applied to a chronically infected, parasitemic C. Felis donor cat (Felis catus) and allowed to feed to repletion. Engorged larvae were collected and held through ecdysis. Three cats were each infested with 66 A. americanum or 66 D. variabilis emerged nymphs. Cytauxzoon Felis infections in principal cats were determined by clinical signs and detection of circulating parasite by blood smear and PCR evaluation. Results Clinical signs of Cytauxzoonosis were observed in cats infested with A. americanum nymphs beginning 12–15 days post-infestation (dpi). The same cats were PCR positive on 12–14 dpi; piroplasms were evident in blood smears at 16 dpi, and macrophage schizonts were observed in stained spleen impression smears in two animals at necropsy. Cats infested with acquisition-fed D. variabilis nymphs remained clinically normal and did not develop detectable parasitemia over the course of the study as determined by blood smear and PCR. Conclusions Cytauxzoon Felis was successfully transmitted to domestic cats by A. americanum nymphs acquisition-fed as larvae on the donor cat. However, we were not able to transmit C. Felis to healthy domestic cats with D. variabilis nymphs that were simultaneously acquisition-fed on the same donor cat. Results from this study suggest that larval and nymphal A. americanum likely play important roles in natural transmission cycles of C. Felis
