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Lu Y, Xu Y, Yu C, Cheng S, Xia Q, Bin Z. Key molecules regulating the blood meals of Rhipicephalus sanguineus (Acari: Ixodidae) revealed by transcriptomics. VETERINARY RESEARCH FORUM : AN INTERNATIONAL QUARTERLY JOURNAL 2024; 15:171-179. [PMID: 38770198 PMCID: PMC11102794 DOI: 10.30466/vrf.2024.2011271.4007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 01/08/2024] [Indexed: 05/22/2024]
Abstract
Rhipicephalus sanguineus, a repulsive obligate blood feeder, is a three-host tick inflicting tremendous damage. Blood-sucking initiates tick-pathogen-host interactions along with alterations in the expression levels of numerous bioactive ingredients. Key molecules regulating blood meals were identified using the transcriptomic approach. A total number of 744 transcripts showed statistically significantly differential expression including 309 significantly upregulated transcripts and 435 significantly downregulated transcripts in semiengorged female ticks compared to unfed ticks, all collected in 2021. The top 10 differentially upregulated transcripts with explicit functional annotations included turripeptide OL55-like protein, valine tRNA ligase-like protein and ice-structuring glycoprotein-like protein. The top 10 differentially down-regulated transcripts were uncharacterized proteins. Gene Ontology (GO) enrichment analysis revealed four associated terms in the cellular component category and 16 in the molecular function category among the top 20 terms. Differentially expressed genes (DEGs) were enriched in GO terms ID 0000323 (lytic vacuole) and ID 0005773 (vacuole). The top 20 enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways included metabolism, cellular processes, organismal systems and human diseases. The DEGs were enriched in the KEGG term ID: ko-04142 (lysosome pathway) associated with intracellular digestion in the tick midgut epithelium. Molecular markers annotated via comparative transcriptomic profiling were expected to be candidate markers for the purpose of tick control.
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Affiliation(s)
- Yajun Lu
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, China;
- Department of Pathogen Biology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, China;
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, China.
| | - Yijia Xu
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, China.
| | - Chenghang Yu
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, China;
| | - Shi Cheng
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, China.
| | - Qianfeng Xia
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, China.
| | - Zheng Bin
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, China;
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Shao L, Wang W, Gong X, Yu Y, Xue J, Zeng X, Liu J. The Toxicity Differences of Fluralaner against the Red Imported Fire Ant ( Solenopsis invicta) at Different Developmental Stages. Int J Mol Sci 2023; 24:15627. [PMID: 37958611 PMCID: PMC10649654 DOI: 10.3390/ijms242115627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 10/18/2023] [Accepted: 10/24/2023] [Indexed: 11/15/2023] Open
Abstract
The red imported fire ant (RIFA), Solenopsis invicta, is an invasive pest that causes damage to agricultural and ecological environments worldwide. Fluralaner is a new isoxazoline pesticide with the potential to become a control agent against RIFA. However, it is not clear whether S. invicta responds the same way to fluralaner at different reproductive stages. The present study firstly evaluated the toxicity of fluralaner to S. invicta at different developmental stages, finding that fourth instar larvae (LD50, 1744.23 mg/kg) and worker ants (LD50, 8.62 mg/kg) were differently susceptible to fluralaner, while the mortality rate of fourth instar larvae was significantly lower at the same concentration of 10 mg/L (5.56 ± 3.14%) than that of worker ants (62.22 ± 3.14%), demonstrating a greater tolerance to fluralaner. Subsequently, the metabolic responses of worker and larval ants to fluralaner stress (10 mg/L) were investigated using non-targeted metabolomics, which indicated that the amount of differential metabolites and the KEGG metabolic pathways enriched were different between workers and larvae when exposed to the same dose (10 mg/L) of fluralaner. Differential metabolites of larvae and worker ants under fluralaner stress were mainly concentrated in organic acids and their derivatives, lipids and lipid-like molecules, nucleosides, nucleotides, and analogues, combined with the enriched metabolic pathways, revealed that the differential metabolic responses of larvae and worker ants were mainly in energy metabolism, detoxification metabolism, and neurotransmitter ligands. Workers consumed more substrates in the arginine synthesis pathway (l-glutamic acid, l-aspartic acid, and fumaric acid) to provide energy for the detoxification (glutathione) of pesticides when exposed to fluralaner stress, and the high accumulation of l-aspartic acid induced excitotoxicity in the worker ants. Larval ants consumed more arachidonic acid to synthesize PG D2, and changes in the metabolism of antioxidants such as catechins, hesperidin, and l-ascorbic acid suggested that larvae were more capable of scavenging the ROS response than worker ants. The results of non-targeted metabolomics successfully revealed differences in the sensitivity of larvae and workers to fluralaner agents, providing insights into the fluralaner control of Solenopsis invicta.
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Affiliation(s)
| | | | | | | | | | | | - Jiali Liu
- College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (L.S.); (W.W.); (X.G.); (Y.Y.); (J.X.); (X.Z.)
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Sodelli LF, Silva OD, Araújo BJN, Camargo-Mathias MI. Liver and spleen of hosts of Rhipicephalus linnaei exposed to synthetic (afoxolaner) and natural acaricides (esters from castor oil). A comparative clinical-morphological study. REVISTA BRASILEIRA DE PARASITOLOGIA VETERINARIA = BRAZILIAN JOURNAL OF VETERINARY PARASITOLOGY : ORGAO OFICIAL DO COLEGIO BRASILEIRO DE PARASITOLOGIA VETERINARIA 2023; 32:e004023. [PMID: 37466625 PMCID: PMC10399553 DOI: 10.1590/s1984-29612023041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 05/30/2023] [Indexed: 07/20/2023]
Abstract
In dogs, Rhipicephalus linnaei transmits pathogens such as Ehrlichia canis, Babesia vogeli, and Hepatozoon canis. The veterinary market has synthetic acaricides to ticks control. Esters derived from castor oil are efficient. However, there is little information about their effects on non-target organisms. This work consisted of a clinical (AST, ALT, and ALP) and histological and histochemical analysis (liver and spleen) of female rabbits exposed to these esters and afoxolaner. The rabbits were divided into three groups: control group (CG) received Bandeirante® rabbit feed; the afoxolaner treatment (TG1) received rabbit feed and two doses of afoxolaner; castor oil esters treatment (TG2) received rabbit feed enriched with esters (1.75 g esters/kg). No alterations were observed in the AST, ALT, and ALP enzymes in exposure to esters TG2. Rabbits from TG1 showed changes in AST. The liver of rabbits exposed to afoxolaner underwent histological and histochemical changes, such as steatosis and vacuolation, as well as poor protein labeling. Polysaccharides were intensely observed in the group exposed to esters. The spleen showed no changes in any of the exposure. Esters from castor oil caused fewer liver changes when incorporated into the feed and fed to rabbits than exposure to afoxolaner.
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Affiliation(s)
- Luís Fernando Sodelli
- Departamento de Biologia Geral e Aplicada, Instituto de Biociências, Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Rio Claro, SP, Brasil
| | - Odaiza da Silva
- Departamento de Biologia Geral e Aplicada, Instituto de Biociências, Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Rio Claro, SP, Brasil
| | - Bruna Jéssyca Nascimento Araújo
- Departamento de Biologia Geral e Aplicada, Instituto de Biociências, Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Rio Claro, SP, Brasil
| | - Maria Izabel Camargo-Mathias
- Departamento de Biologia Geral e Aplicada, Instituto de Biociências, Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Rio Claro, SP, Brasil
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Ehrlichiosis in Dogs: A Comprehensive Review about the Pathogen and Its Vectors with Emphasis on South and East Asian Countries. Vet Sci 2022; 10:vetsci10010021. [PMID: 36669021 PMCID: PMC9863373 DOI: 10.3390/vetsci10010021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 12/17/2022] [Accepted: 12/24/2022] [Indexed: 12/31/2022] Open
Abstract
Ehrlichiosis in dogs is an emerging vector borne rickettsial zoonotic disease of worldwide distribution. In general, three Ehrlichial species (Ehrlichia canis, E. ewingii, and E. chaffeensis) are involved in infecting dogs. Among them, E. canis is the well-known etiological pathogen affecting platelets, monocytes, and granulocytes. Dogs act as a reservoir, while the main vector responsible for disease transmission is Rhipicephalus sanguineus. However, in east Asian countries, Haemaphysalis longicornis is considered the principal vector for disease transmission. This disease affects multiple organs and systems and has three clinical manifestations, including acute, subclinical, and chronic. Definitive diagnosis involves visualization of morulae on cytology, detection of antibodies through an indirect immunofluorescence test (IFAT), and DNA amplification by polymerase chain reaction (PCR). In canine ehrlichiosis, no predilection of age or sex is observed; however, Siberian Huskies and German Shepherds are more likely to develop severe clinical manifestations. Doxycycline, rifampicin, and minocycline are proven to be effective drugs against canine ehrlichiosis. This review is intended to describe a brief overview of Ehrlichia infection in dogs, its reported prevalence in east and south Asian countries, and the latest knowledge regarding chemotherapy and associated vectors responsible for the disease transmission. This manuscript also identifies the prevailing knowledge gaps which merit further attention by the scientific community.
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Liu Z, Khan MM, Fajar A, Chen S, Guo M, Chen Y, Yang C, Wu J, Qiu B, Zhou X, Pan H. Toxicity of fluralaner against vegetable pests and its sublethal impact on a biocontrol predatory ladybeetle. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 225:112743. [PMID: 34481350 DOI: 10.1016/j.ecoenv.2021.112743] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/19/2021] [Accepted: 08/30/2021] [Indexed: 06/13/2023]
Abstract
Fluralaner, a systemic pesticide, was originally registered with the US Food and Drug Administration in 2014 under the trade name Bravecto for flea treatment for pets. As a GABA antagonist, the footprint of fluralaner has expended beyond medical and veterinary pests in recent years. In this study, we examined the acute toxicity of fluralaner against three pests of Henosepilachna vigintioctopunctata, Megalurothrips usitatus, and Phyllotreta striolata in the Solanaceae, Fabaceae, and Cruciferae families, respectively, and the sublethal impact of fluralaner on Propylaea japonica, a widely distributed predatory ladybeetle. Based on LC50, fluralaner was effective against H. vigintioctopunctata (0.098 mg a.i. L-1 for the second instar larvae), M. usitatus (0.134 mg a.i. L-1 for adult females), and P. striolata (0.595 mg a.i. L-1 for adults). For P. japonica, however, fluralaner was substantially less effective (1.177 mg a.i. L-1 for the third instar larvae). Furthermore, the LC10 and LC30 of P. japonica were also consistently higher than the LC50 of the three pests. In addition, we did not observe any significant impacts of fluralaner at LC10 and LC30 on the life history traits, including body weight, developmental time, pre-oviposition period, and fecundity of P. japonica. Based on our results from acute toxicities and sublethal impacts, fluralaner is effective against vegetable pests, while potentially friendly to P. japonica when employed as a biological control agent.
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Affiliation(s)
- Zhuoqi Liu
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou 510642, China
| | - Muhammad Musa Khan
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou 510642, China
| | - Anugerah Fajar
- Department of Entomology, University of Kentucky, Lexington, KY 40546, USA; Research Center for Biomaterials, Indonesia Institute of Sciences, Jl. Raya Bogor km. 46, Cibinong, Bogor 16911, West Java, Indonesia
| | - Shimin Chen
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou 510642, China
| | - Mujuan Guo
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou 510642, China
| | - Yueyin Chen
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou 510642, China
| | - Chunxiao Yang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou 510642, China
| | - Jianhui Wu
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou 510642, China
| | - Baoli Qiu
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou 510642, China
| | - Xuguo Zhou
- Department of Entomology, University of Kentucky, Lexington, KY 40546, USA.
| | - Huipeng Pan
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou 510642, China.
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Toxicity of fluralaner, a companion animal insecticide, relative to industry-leading agricultural insecticides against resistant and susceptible strains of filth flies. Sci Rep 2020; 10:11166. [PMID: 32636470 PMCID: PMC7341816 DOI: 10.1038/s41598-020-68121-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Accepted: 06/10/2020] [Indexed: 01/11/2023] Open
Abstract
Filth flies cause billions of dollars of losses annually to the animal production industry. Fluralaner is a relatively new pesticide currently sold for control of fleas, ticks, and mites on companion animals and poultry. We examined the efficacy of fluralaner against three species of filth flies. Insecticide-susceptible horn flies and stable flies were tested topically. Fluralaner outperformed permethrin by > 2-fold for the horn flies but underperformed permethrin by > 45-fold for stable flies at 24 h. House flies were tested topically with fluralaner in comparison to permethrin at 48 h and orally with fluralaner in comparison to imidacloprid at 24 h. Topical fluralaner was 6- to 28-fold as toxic as permethrin in four pyrethroid-resistant strains and not significantly less toxic than permethrin in a susceptible strain and a mildly pyrethroid-resistant strain. There was slight cross-resistance between topically applied fluralaner and permethrin in all five insecticide-resistant strains tested. Oral fluralaner was more toxic than imidacloprid in all four house fly strains tested, 9- to 118-fold as toxic. Oral cross-resistance between imidacloprid and fluralaner was not detected, but imidacloprid resistance was not high in any of the tested strains. Fluralaner shows promise for control of horn flies and house flies.
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Konig IFM, Oliveira MVS, Gonçalves RRP, Peconick AP, Thomasi SS, Anholeto LA, Lima-de-Souza JR, Camargo-Mathias MI, Remedio RN. Low concentrations of acetylcarvacrol induce drastic morphological damages in ovaries of surviving Rhipicephalus sanguineus sensu lato ticks (Acari: Ixodidae). Micron 2020; 129:102780. [DOI: 10.1016/j.micron.2019.102780] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 11/07/2019] [Accepted: 11/07/2019] [Indexed: 12/16/2022]
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The brown dog tick Rhipicephalus sanguineus sensu Roberts, 1965 across Australia: Morphological and molecular identification of R. sanguineus s.l. tropical lineage. Ticks Tick Borne Dis 2019; 11:101305. [PMID: 31594688 DOI: 10.1016/j.ttbdis.2019.101305] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 08/13/2019] [Accepted: 09/21/2019] [Indexed: 12/14/2022]
Abstract
The brown dog tick Rhipicephalus sanguineus (Latreille, 1806) is the most widely distributed tick species globally. Throughout the world there are at least two divergent lineages on dogs that are traditionally grouped into what was known as R. sanguineus. The species R. sanguineus was recently redescribed using a neotype reported from countries with a temperate climate. The second lineage distributed in countries with primarily tropical climates is currently designated R. sanguineus s.l. tropical lineage. Here, we present a comprehensive genetic evaluation of Australian brown dog ticks from across the continent that complements the morphological study of R. sanguineus sensu Roberts (1965). A total of 294 ticks were collected from dogs around Australia - including New South Wales, Queensland, the Northern Territory and Western Australia - for morphological identification. All ticks were morphologically identified as R. sanguineus sensu Roberts (1965). DNA was isolated from a single leg from morphologically characterised individuals from New South Wales (n = 14), Queensland (n = 18), Northern Territory (n = 7) and Western Australia (n = 13), together with ticks from Fiji (n = 1) and the Seychelles (n = 1) for comparison with Australian ticks. The study revealed three cox1 haplotypes clustered only with R. sanguineus s.l. tropical lineage'. An updated distribution of R. sanguineus sensu Roberts (1965) is compared to the 1965 distribution. In the Australian context, R. sanguineus s.l. has appeared in north-western New South Wales but remains absent from coastal New South Wales. Despite both temperate and tropical climates being present in Australia, only R. sanguineus s.l. tropical lineage was found. The evidence does not support the presence of the strictly defined brown dog tick, R. sanguineus by Nava et al. (2018) in Australia, because the examined ticks are genetically and morphologically distinct. We recommend using the term brown dog tick, R. sanguineus sensu Roberts (1965) for specimens from Australia.
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Littman MP, Gerber B, Goldstein RE, Labato MA, Lappin MR, Moore GE. ACVIM consensus update on Lyme borreliosis in dogs and cats. J Vet Intern Med 2018; 32:887-903. [PMID: 29566442 PMCID: PMC5980284 DOI: 10.1111/jvim.15085] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 01/26/2018] [Accepted: 01/30/2018] [Indexed: 12/16/2022] Open
Abstract
An update of the 2006 American College of Veterinary Internal Medicine (ACVIM) Small Animal Consensus Statement on Lyme Disease in Dogs: Diagnosis, Treatment, and Prevention was presented at the 2016 ACVIM Forum in Denver, CO, followed by panel and audience discussion and a drafted consensus statement distributed online to diplomates for comment. The updated consensus statement is presented below. The consensus statement aims to provide guidance on the diagnosis, treatment, and prevention of Lyme borreliosis in dogs and cats.
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Affiliation(s)
- Meryl P. Littman
- Department of Clinical Studies‐PhiladelphiaUniversity of Pennsylvania School of Veterinary MedicinePhiladelphiaPennsylvania
| | - Bernhard Gerber
- The Clinic for Small Animal Internal MedicineVetsuisse Faculty, University of ZurichSwitzerland
| | | | - Mary Anna Labato
- Department of Clinical Sciences, Cummings School of Veterinary MedicineTufts UniversityNorth GraftonMassachusetts
| | - Michael R. Lappin
- Department of Clinical Sciences, College of Veterinary Medicine and Biomedical SciencesColorado State UniversityFort CollinsColorado
| | - George E. Moore
- Department of Veterinary Administration, College of Veterinary MedicinePurdue UniversityWest LafayetteIndiana
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Cavalleri D, Murphy M, Gorbea RL, Seewald W, Drake J, Nanchen S. Laboratory evaluations of the immediate and sustained effectiveness of lotilaner (Credelio™) against three common species of ticks affecting dogs in Europe. Parasit Vectors 2017; 10:527. [PMID: 29089050 PMCID: PMC5664927 DOI: 10.1186/s13071-017-2477-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 10/12/2017] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND There is a continuing need for novel approaches to tick control in dogs. One such approach lies in the ability of lotilaner (Credelio™), an isoxazoline with a rapid onset of action, to provide sustained efficacy against ticks. Two studies were undertaken to confirm lotilaner's efficacy, at the minimum dose rate of 20 mg/kg, against the three most common tick species in Europe. METHODS In each of two studies, 16 Beagle dogs, at least 6 months old, were ranked and blocked by tick counts from infestations placed approximately 1 week before treatment. Within blocks, dogs were randomized to receive either lotilaner flavoured chewable tablets at as close as possible to, but not less than the minimum dose rate of 20 mg/kg, or to be sham-treated controls. Study 1 assessed lotilaner efficacy against concurrent infestations with 50 (± 6) Rhipicephalus sanguineus and 70 (± 6) Ixodes ricinus; Study 2 infestations were with 50 (± 2) Dermacentor reticulatus. Infestations were performed on Day -2 with counts on Day 2, 48 (± 2) hours post-treatment. Post-treatment infestations were performed on Days 7, 14, 21, 28 and 35, and ticks were counted 48 (±2) hours post-infestations. Efficacy was determined by the percent reduction in mean live tick counts. RESULTS Control group infestations for each tick species were adequate for assessing lotilaner efficacy at all assessment times. On Day 2 no live ticks were found on any lotilaner-treated dog. For subsequent counts, in Study 1 lotilaner was 100% effective in eliminating live I. ricinus and R. sanguineus on all but two occasions for each tick; on each of those occasions efficacy was sustained at greater than 98.0%. In Study 2, except for a single unattached live tick found on Day 16, efficacy against D. reticulatus was 100% at every post-treatment assessment. CONCLUSION The high and sustained efficacy against the three common species of ticks in Europe, R. sanguineus, I. ricinus and D. reticulatus, demonstrates that lotilaner can be a valuable tool in the treatment of canine tick infestations. Lotilaner flavoured chewable tablets were well tolerated and effectiveness was sustained through at least 35 days.
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Affiliation(s)
| | - Martin Murphy
- Elanco Animal Health, Mattenstrasse 24a, 4058 Basel, Switzerland
| | | | - Wolfgang Seewald
- Elanco Animal Health, Mattenstrasse 24a, 4058 Basel, Switzerland
| | - Jason Drake
- Elanco Animal Health, 2500 Innovation Way, Greenfield, Indiana 46140 USA
| | - Steve Nanchen
- Elanco Animal Health, Mattenstrasse 24a, 4058 Basel, Switzerland
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Mylonakis ME, Theodorou KN. Canine Monocytic Ehrlichiosis: An Update on Diagnosis and Treatment. ACTA VET-BEOGRAD 2017. [DOI: 10.1515/acve-2017-0025] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Abstract
Canine monocytic ehrlichiosis (CME) is a tick-borne disease of worldwide distribution. The major causative agent is Ehrlichia canis, a gram-negative, obligate intracellular, pleomorphic bacterium of the genus Ehrlichia, which infects monocytes, macrophages and lymphocytes, forming intracytoplasmic, membrane-bound bacterial aggregates, called morulae. After an incubation period of 8-20 days, the course of E. canis infection, can be sequentially divided into acute, subclinical and chronic phases, although these phases can hardly be distinguished in the clinical setting. Clinical recovery is the typical outcome of acutely infected dogs, entering the subclinical phase, during which they show no or minimal clinical signs and/or mild hematological abnormalities. Immunocompetent dogs may eliminate the infection during the acute or subclinical phases, but an unpredictable proportion of dogs will eventually develop the chronic phase, characterized by aplastic pancytopenia and high mortality, due to septicemia and/or severe bleeding. This article outlines briefly the pathogenesis of CME due to E. canis, and more thoroughly reviews the recent scientific literature pertaining to the diagnosis and treatment of this devastating disease.
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Affiliation(s)
- Mathios E. Mylonakis
- Konstantina N. Companion Animal Clinic, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki , Greece
| | - Konstantina N. Theodorou
- Companion Animal Clinic, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki , Greece
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Loza A, Talaga A, Herbas G, Canaviri RJ, Cahuasiri T, Luck L, Guibarra A, Goncalves R, Pereira JA, Gomez SA, Picado A, Messenger LA, Bern C, Courtenay O. Systemic insecticide treatment of the canine reservoir of Trypanosoma cruzi induces high levels of lethality in Triatoma infestans, a principal vector of Chagas disease. Parasit Vectors 2017; 10:344. [PMID: 28724448 PMCID: PMC5518140 DOI: 10.1186/s13071-017-2278-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Accepted: 07/06/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Despite large-scale reductions in Chagas disease prevalence across Central and South America, Trypanosoma cruzi infection remains a considerable public health problem in the Gran Chaco region where vector-borne transmission persists. In these communities, peridomestic animals are major blood-meal sources for triatomines, and household presence of infected dogs increases T. cruzi transmission risk for humans. To address the pressing need for field-friendly, complementary methods to reduce triatomine infestation and interrupt T. cruzi transmission, this study evaluated the systemic activity of three commercial, oral, single dose insecticides Fluralaner (Bravecto®), Afoxolaner (NexGard®) and Spinosad (Comfortis®) in canine feed-through assays against Triatoma infestans, the principal domestic vector species in the Southern Cone of South America. METHODS Twelve healthy, outbred dogs were recruited from the Zoonosis Surveillance and Control Program in Santa Cruz, Bolivia, and randomized to three treatment groups, each containing one control and three treated dogs. Following oral drug administration, colony-reared second and third stage T. infestans instars were offered to feed on dogs for 30 min at 2, 7, 21, 34 and 51 days post-treatment. RESULTS Eighty-five per cent (768/907) of T. infestans successfully blood-fed during bioassays, with significantly higher proportions of bugs becoming fully-engorged when exposed to Bravecto® treated dogs (P < 0.001) for reasons unknown. Exposure to Bravecto® or NexGard® induced 100% triatomine mortality in fully- or semi-engorged bugs within 5 days of feeding for the entire follow-up period. The lethality effect for Comfortis® was much lower (50-70%) and declined almost entirely after 51 days. Instead Comfortis® treatment resulted in substantial morbidity; of these, 30% fully recovered whereas 53% remained morbid after 120 h, the latter subsequently unable to feed 30 days later. CONCLUSIONS A single oral dose of Fluralaner or Afoxolaner was safe and well tolerated, producing complete triatomine mortality on treated dogs over 7.3 weeks. While both drugs were highly efficacious, more bugs exposed to Fluralaner took complete blood-meals, and experienced rapid knock-down. Coupled with its longer residual activity, Fluralaner represents an ideal insecticide for development into a complementary, operationally-feasible, community-level method of reducing triatomine infestation and potentially controlling T. cruzi transmission, in the Gran Chaco region.
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Affiliation(s)
- Ariel Loza
- Facultad de Ciencias Veterinarias, Universidad Autonóma Gabriel René Moreno (UAGRM), Santa Cruz, Bolivia
| | - Adrianna Talaga
- University of Warwick, Gibbet Hill Campus, Coventry, CV4 7AL, UK
| | - Gladys Herbas
- Facultad de Ciencias Veterinarias, Universidad Autonóma Gabriel René Moreno (UAGRM), Santa Cruz, Bolivia
| | - Ruben Jair Canaviri
- Facultad de Ciencias Veterinarias, Universidad Autonóma Gabriel René Moreno (UAGRM), Santa Cruz, Bolivia
| | - Thalia Cahuasiri
- Facultad de Ciencias Veterinarias, Universidad Autonóma Gabriel René Moreno (UAGRM), Santa Cruz, Bolivia
| | - Laura Luck
- Facultad de Ciencias Veterinarias, Universidad Autonóma Gabriel René Moreno (UAGRM), Santa Cruz, Bolivia
| | - Alvaro Guibarra
- Facultad de Ciencias Veterinarias, Universidad Autonóma Gabriel René Moreno (UAGRM), Santa Cruz, Bolivia
| | - Raquel Goncalves
- University of Warwick, Gibbet Hill Campus, Coventry, CV4 7AL, UK
| | - Juan Antonio Pereira
- Facultad de Ciencias Veterinarias, Universidad Autonóma Gabriel René Moreno (UAGRM), Santa Cruz, Bolivia
| | - Sonia A Gomez
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clinic - Universitat de Barcelona, Rosello 132, 08036, Barcelona, Spain
| | - Albert Picado
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clinic - Universitat de Barcelona, Rosello 132, 08036, Barcelona, Spain
| | | | - Caryn Bern
- University of California-San Francisco, 550 16th St, 94158, San Francisco, CA, USA
| | - Orin Courtenay
- University of Warwick, Gibbet Hill Campus, Coventry, CV4 7AL, UK
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