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Nepveu-Traversy ME, Fausther-Bovendo H, Babuadze G(G. Human Tick-Borne Diseases and Advances in Anti-Tick Vaccine Approaches: A Comprehensive Review. Vaccines (Basel) 2024; 12:141. [PMID: 38400125 PMCID: PMC10891567 DOI: 10.3390/vaccines12020141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 01/18/2024] [Accepted: 01/23/2024] [Indexed: 02/25/2024] Open
Abstract
This comprehensive review explores the field of anti-tick vaccines, addressing their significance in combating tick-borne diseases of public health concern. The main objectives are to provide a brief epidemiology of diseases affecting humans and a thorough understanding of tick biology, traditional tick control methods, the development and mechanisms of anti-tick vaccines, their efficacy in field applications, associated challenges, and future prospects. Tick-borne diseases (TBDs) pose a significant and escalating threat to global health and the livestock industries due to the widespread distribution of ticks and the multitude of pathogens they transmit. Traditional tick control methods, such as acaricides and repellents, have limitations, including environmental concerns and the emergence of tick resistance. Anti-tick vaccines offer a promising alternative by targeting specific tick proteins crucial for feeding and pathogen transmission. Developing vaccines with antigens based on these essential proteins is likely to disrupt these processes. Indeed, anti-tick vaccines have shown efficacy in laboratory and field trials successfully implemented in livestock, reducing the prevalence of TBDs. However, some challenges still remain, including vaccine efficacy on different hosts, polymorphisms in ticks of the same species, and the economic considerations of adopting large-scale vaccine strategies. Emerging technologies and approaches hold promise for improving anti-tick vaccine development and expanding their impact on public health and agriculture.
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Affiliation(s)
| | - Hugues Fausther-Bovendo
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX 75550, USA;
| | - George (Giorgi) Babuadze
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX 75550, USA;
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Bonnet SI, Vourc’h G, Raffetin A, Falchi A, Figoni J, Fite J, Hoch T, Moutailler S, Quillery E. The control of Hyalomma ticks, vectors of the Crimean–Congo hemorrhagic fever virus: Where are we now and where are we going? PLoS Negl Trop Dis 2022; 16:e0010846. [PMCID: PMC9671348 DOI: 10.1371/journal.pntd.0010846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
At a time of major global, societal, and environmental changes, the shifting distribution of pathogen vectors represents a real danger in certain regions of the world as generating opportunities for emergency. For example, the recent arrival of the Hyalomma marginatum ticks in southern France and the concurrent appearance of cases of Crimean–Congo hemorrhagic fever (CCHF)—a disease vectored by this tick species—in neighboring Spain raises many concerns about the associated risks for the European continent. This context has created an urgent need for effective methods for control, surveillance, and risk assessment for ticks and tick-borne diseases with a particular concern regarding Hyalomma sp. Here, we then review the current body of knowledge on different methods of tick control—including chemical, biological, genetical, immunological, and ecological methods—and the latest developments in the field, with a focus on those that have been tested against ticks from the genus Hyalomma. In the absence of a fully and unique efficient approach, we demonstrated that integrated pest management combining several approaches adapted to the local context and species is currently the best strategy for tick control together with a rational use of acaricide. Continued efforts are needed to develop and implement new and innovative methods of tick control. Disease-bearing Hyalomma ticks are an increasingly emerging threat to humans and livestock worldwide. Various chemical, biological, genetic, and ecological methods for tick control have been developed, with variable efficiencies. Today, the best tick control strategy involves an integrated pest management approach.
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Affiliation(s)
- Sarah I. Bonnet
- Animal Health Department, INRAE, Nouzilly, France
- Ecology and Emergence of Arthropod-borne Pathogens Unit, Institut Pasteur, CNRS UMR 2000, Université Paris-cité, Paris, France
- * E-mail:
| | - Gwenaël Vourc’h
- Université Clermont Auvergne, INRAE, VetAgro Sup, UMR EPIA, Saint-Genès-Champanelle, France
- Université de Lyon, INRAE, VetAgro Sup, UMR EPIA, Marcy l’Etoile, France
| | - Alice Raffetin
- Reference Centre for Tick-Borne Diseases, Paris and Northern Region, Department of Infectious Diseases, General Hospital of Villeneuve-Saint-Georges, 40 allée de la Source, Villeneuve-Saint-Georges, France
- EA 7380 Dynamyc, UPEC, Créteil, France
- Unité de recherche EpiMAI, USC ANSES, Ecole Nationale Vétérinaire d’Alfort, Maisons-Alfort, France
| | - Alessandra Falchi
- UR7310, Faculté de Sciences, Campus Grimaldi, Université de Corse, Corte, France
| | - Julie Figoni
- Santé publique France, 94410 Saint-Maurice, France
| | - Johanna Fite
- French Agency for Food, Environmental and Occupational Health & Safety, 14 rue Pierre et Marie Curie, Maisons-Alfort Cedex, France
| | | | - Sara Moutailler
- ANSES, INRAE, Ecole Nationale Vétérinaire d’Alfort, UMR BIPAR, Laboratoire de Santé Animale, Maisons-Alfort, France
| | - Elsa Quillery
- French Agency for Food, Environmental and Occupational Health & Safety, 14 rue Pierre et Marie Curie, Maisons-Alfort Cedex, France
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Kumar B, Manjunathachar HV, Ghosh S. A review on Hyalomma species infestations on human and animals and progress on management strategies. Heliyon 2020; 6:e05675. [PMID: 33319114 PMCID: PMC7726666 DOI: 10.1016/j.heliyon.2020.e05675] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/23/2020] [Accepted: 12/03/2020] [Indexed: 12/12/2022] Open
Abstract
The Hyalomma species of ticks have gained additional attention due to their role in the transmission of Theileria annulata infection in animals and the Crimean-Congo Haemorrhagic Fever (CCHF) virus in humans. Apart from these, many other pathogens viz., other species of Theileria, a few species of Babesia, Rickettsia and viruses are either maintained or transmitted by this tick species. The medium to large size species with longer proboscis has inflicted additional burden on the overall impact of tick infestations. Being a multi-host species, management of the species is very challenging. Presently, the traditional method of tick management using chemical acaricides is found insufficient and unsustainable. Henceforth, the overall burden of tick infestations and tick-borne diseases are increasing gradually. After the successful development of vaccines against cattle tick, Rhipicephalus microplus, the anti-Hyalomma vaccine is considered a feasible and sustainable management option. In the recent past research on herbal acaricides and its possible application for tick control seems promising. Other eco-friendly methods are still under experimental stage. The present review is focused on impact of Hyalomma species infestation on human and animal health with special emphasis on progress on its sustainable management.
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Affiliation(s)
- Binod Kumar
- Department of Veterinary Parasitology, College of Veterinary Science & Animal Husbandry, Junagadh Agricultural University, Junagadh 362001, Gujarat, India
| | | | - Srikanta Ghosh
- Entomology Laboratory, Division of Parasitology, ICAR-Indian Veterinary Research Institute (IVRI), Izatnagar, 243122, Bareilly, India
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Bhowmick B, Han Q. Understanding Tick Biology and Its Implications in Anti-tick and Transmission Blocking Vaccines Against Tick-Borne Pathogens. Front Vet Sci 2020; 7:319. [PMID: 32582785 PMCID: PMC7297041 DOI: 10.3389/fvets.2020.00319] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Accepted: 05/11/2020] [Indexed: 12/13/2022] Open
Abstract
Ticks are obligate blood-feeding ectoparasites that transmit a wide variety of pathogens to animals and humans in many parts of the world. Currently, tick control methods primarily rely on the application of chemical acaricides, which results in the development of resistance among tick populations and environmental contamination. Therefore, an alternative tick control method, such as vaccines have been shown to be a feasible strategy that offers a sustainable, safe, effective, and environment-friendly solution. Nevertheless, novel control methods are hindered by a lack of understanding of tick biology, tick-pathogen-host interface, and identification of effective antigens in the development of vaccines. This review highlights the current knowledge and data on some of the tick-protective antigens that have been identified for the formulation of anti-tick vaccines along with the effects of these vaccines on the control of tick-borne diseases.
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Affiliation(s)
- Biswajit Bhowmick
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China
- Laboratory of Tropical Veterinary Medicine and Vector Biology, School of Life and Pharmaceutical Sciences, Hainan University, Haikou, China
| | - Qian Han
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China
- Laboratory of Tropical Veterinary Medicine and Vector Biology, School of Life and Pharmaceutical Sciences, Hainan University, Haikou, China
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Sajid M, Kausar A, Iqbal A, Abbas H, Iqbal Z, Jones M. An insight into the ecobiology, vector significance and control of Hyalomma ticks (Acari: Ixodidae): A review. Acta Trop 2018; 187:229-239. [PMID: 30118698 DOI: 10.1016/j.actatropica.2018.08.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 08/10/2018] [Accepted: 08/12/2018] [Indexed: 12/28/2022]
Abstract
Ticks (Acari:Ixodoidea) are important ectoparasites infesting livestock and human populations around the globe. Ticks can cause damage directly by affecting the site of infestation, or indirectly as vectors of a wide range of protozoa, bacteria and viruses which ultimately lead to lowered productivity of livestock populations. Hyalomma is a genus of hard ticks, having more than 30 species well-adapted to hot, humid and cold climates. Habitat diversity, vector ability, and emerging problem of acaricidal resistance in enzootic regions typify this genus in various countries around the world. This paper reviews the epidemiology, associated risk factors (temperature, climate, age, sex, breed etc.), vector role, vector-pathogen association, and reported control strategies of genus Hyalomma. The various proteins in saliva of Hyalomma secreted into the blood stream of host and the prolonged attachment are responsible for the successful engorgement of female ticks in spite of host immune defense system. The various immunological approaches that have been tried by researchers in order to cause tick rejection are also discussed. In addition, the novel biological control approaches involving the use of entomo-pathogenic nematodes and Bacillus thuringiensis (B. thuringiensis) serovar thuringiensis H14; an endotoxin, for their acaricidal effect on different species and life cycle stages of Hyalomma are also presented.
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Kumar B, Ray DD, Ghosh S. Immune responses against rHaa86 in cross-bred cattle. J Parasit Dis 2015; 39:292-7. [PMID: 26064021 DOI: 10.1007/s12639-013-0347-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 06/29/2013] [Indexed: 10/26/2022] Open
Abstract
Tick vaccines are important component of integrated pest management for sustainable control of tick and tick born diseases. Immune responses against rHaa86 (homologue of Bm86) recombinant Hyalomma tick antigen were determined in experimental crossbred calves. The humoral antibody responses of the calves were measured against rHaa86 in an optimized ELISA format. The expression of the interferon gamma (IFN-γ), was also evaluated in the culture supernatant of blood culture from blood samples of the experimental calves. The expression patterns were studied after stimulating the blood cells in vitro with rHaa86 antigen and subsequently optical density was measured against IFN-γ. The results were expressed as stimulation indices. All the rHaa86 immunized animal showed strong humoral antibody response just after 1st vaccination and reach to pick after 2nd booster and thereafter maintained up to days 120 from post primary immunization. The humoral antibody response was dominated by IgG1 against IgG2 throughout the period of antibody monitoring. The standard graph of bovine recombinant IFN-γ was plotted which showed a significant difference in SI and OD value up to 200 pg/ml. The lowest detectable value of IFN-γ was 20 pg/ml and SI at this level is 1.16 which is greater than maximum SI calculated from individual calf. The IFN-γ response never reached at significant level and the IgG1 response was dominated over IgG2 response throughout the period of experiment. Since IgG2 and IFN-γ are interlinked, the present study established the Th2 response as a possible mode of mechanism of conferring antibody mediated protection against challenged ticks.
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Affiliation(s)
- Binod Kumar
- Entomology Laboratory, Division of Parasitology, Indian Veterinary Research Institute, Izatnagar, 243122 Uttar Pradesh India ; Department of Veterinary Parasitology, College of Veterinary Science and Animal Husbandry, Junagadh Agricultural University, Junagadh, 362001 Gujarat India
| | - D D Ray
- Entomology Laboratory, Division of Parasitology, Indian Veterinary Research Institute, Izatnagar, 243122 Uttar Pradesh India
| | - Srikant Ghosh
- Entomology Laboratory, Division of Parasitology, Indian Veterinary Research Institute, Izatnagar, 243122 Uttar Pradesh India
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Ghosh S, Tiwari SS, Kumar B, Srivastava S, Sharma AK, Kumar S, Bandyopadhyay A, Julliet S, Kumar R, Rawat AKS. Identification of potential plant extracts for anti-tick activity against acaricide resistant cattle ticks, Rhipicephalus (Boophilus) microplus (Acari: Ixodidae). EXPERIMENTAL & APPLIED ACAROLOGY 2015; 66:159-171. [PMID: 25717008 DOI: 10.1007/s10493-015-9890-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 02/17/2015] [Indexed: 06/04/2023]
Abstract
To develop an eco-friendly tick control method, seven plant extracts were prepared using 50 and 95% ethanol and evaluated for acaricidal activity against cattle tick, Rhipicephalus (Boophilus) microplus. The adult immersion test was adopted for testing different extracts. Based on 72 h screening criterion, 95% ethanolic extracts of Datura metel fruits and Argemone mexicana whole plant were found effective showing more than 50% mortality of treated ticks. The 95% ethanolic extracts of D. metel fruits and A. mexicana whole plant exhibited acaricidal and reproductive inhibitory effects on treated ticks. The LC90 values of D. metel and A. mexicana extracts were determined as 7.13 and 11.3%, respectively. However, although both the extracts were found efficacious against deltamethrin-resistant IVRI-4 and multi-acaricide resistant IVRI-5 lines of R. (B.) microplus, they caused less mortality than treated ticks of the reference IVRI-I line. Phytochemical studies indicated the presence of alkaloids and glucosides in D. metel fruits and alkaloids, terpenoids, flavonoids and phenolics in A. mexicana whole plant extracts. The results indicated that these botanicals may play an important role in reducing the use of chemicals for tick control and possibly to manage resistant tick population in environment friendly manner.
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Affiliation(s)
- Srikanta Ghosh
- Entomology Laboratory, Division of Parasitology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, 243122, UP, India,
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Cunha RC, Andreotti R, Garcia MV, Aguirre ADAR, Leitão A. Calculation of the efficacy of vaccines against tick infestations on cattle. REVISTA BRASILEIRA DE PARASITOLOGIA VETERINARIA 2013; 22:571-8. [DOI: 10.1590/s1984-29612013000400019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 09/02/2013] [Indexed: 12/13/2022]
Abstract
Cattle ticks are responsible for great economic losses in cattle farming worldwide, and their main control method, chemicals, has been showing problems, whether resulting from the development of resistant strains of ticks or environmental contamination. Research studies directed toward developing vaccines against ticks are emerging. One way to evaluate those vaccines is to calculate the percentage of efficacy. The aim of this study was to analyze scientific publications archived in PubMed that used this method of assessment and discuss the main factors that may affect its calculation. Thus, 25 articles addressing this subject were selected. The percentage of efficacy was usually calculated in one of two ways, with one considering the reduced fertility of eggs and the other not. The latter method may underestimate the vaccine efficacy, and the most complete formula for calculating the efficacy reflects how much the vaccine actually affects the infestation. In our view, the use of the complete formula for calculating the percentage of efficacy is broader and more representative of the vaccine effect on the tick population.
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Merino O, Alberdi P, Pérez de la Lastra JM, de la Fuente J. Tick vaccines and the control of tick-borne pathogens. Front Cell Infect Microbiol 2013; 3:30. [PMID: 23847771 PMCID: PMC3705209 DOI: 10.3389/fcimb.2013.00030] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 06/21/2013] [Indexed: 11/14/2022] Open
Abstract
Ticks are obligate hematophagous ectoparasites that transmit a wide variety of pathogens to humans and animals. The incidence of tick-borne diseases has increased worldwide in both humans and domestic animals over the past years resulting in greater interest in the study of tick-host-pathogen interactions. Advances in vector and pathogen genomics and proteomics have moved forward our knowledge of the vector-pathogen interactions that take place during the colonization and transmission of arthropod-borne microbes. Tick-borne pathogens adapt from the vector to the mammalian host by differential gene expression thus modulating host processes. In recent years, studies have shown that targeting tick proteins by vaccination can not only reduce tick feeding and reproduction, but also the infection and transmission of pathogens from the tick to the vertebrate host. In this article, we review the tick-protective antigens that have been identified for the formulation of tick vaccines and the effect of these vaccines on the control of tick-borne pathogens.
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Affiliation(s)
- Octavio Merino
- SaBio, Instituto de Investigación en Recursos Cinegéticos IREC-CSIC-UCLM-JCCM Ciudad Real, Spain
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Ghosh S, Tiwari SS, Srivastava S, Sharma AK, Kumar S, Ray DD, Rawat AKS. Acaricidal properties of Ricinus communis leaf extracts against organophosphate and pyrethroids resistant Rhipicephalus (Boophilus) microplus. Vet Parasitol 2013; 192:259-67. [PMID: 23084038 DOI: 10.1016/j.vetpar.2012.09.031] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Revised: 09/24/2012] [Accepted: 09/24/2012] [Indexed: 11/25/2022]
Abstract
Indian cattle ticks have developed resistance to commonly used acaricides and an attempt has been made to formulate an ecofriendly herbal preparation for the control of acaricide resistant ticks. A 95% ethanolic extract of Ricinus communis was used to test the efficacy against reference acaricide resistant lines by in vitro assay. In in vitro assay, the extract significantly affects the mortality rate of ticks in dose-dependent manner ranging from 35.0 ± 5.0 to 95.0 ± 5.0% with an additional effect on reproductive physiology of ticks by inhibiting 36.4-63.1% of oviposition. The leaf extract was found effective in killing 48.0, 56.7 and 60.0% diazinon, deltamethrin and multi-acaricide resistant ticks, respectively. However, the cidal and oviposition limiting properties of the extract were separated when the extract was fractionated with hexane, chloroform, n-butanol and water. The HPTLC finger printing profile of R. communis leaf extract under λ(max.) - 254 showed presence of quercetin, gallic acid, flavone and kaempferol which seemed to have synergistic acaricidal action. In vivo experiment resulted in 59.9% efficacy on Ist challenge, however, following 2nd challenge the efficacy was reduced to 48.5%. The results indicated that the 95% ethanolic leaf extract of R. communis can be used effectively in integrated format for the control of acaricide resistant ticks.
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Affiliation(s)
- Srikanta Ghosh
- Entomology Laboratory, Parasitology Division, Indian Veterinary Research Institute, Izatnagar, Bareilly 243122, UP, India.
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Immune Response of Bos indicus Cattle against the Anti-Tick Antigen Bm91 Derived from Local Rhipicephalus (Boophilus) microplus Ticks and Its Effect on Tick Reproduction under Natural Infestation. J Parasitol Res 2012; 2012:907607. [PMID: 23213489 PMCID: PMC3507137 DOI: 10.1155/2012/907607] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 10/16/2012] [Accepted: 10/19/2012] [Indexed: 11/22/2022] Open
Abstract
Antigens of anti-tick vaccines are more efficacious for homologous challenge with local tick strains. cDNA clones encoding for Bm91 from local Rhipicephalus (Boophilus) microplus strains were developed to immunize Bos indicus cattle under field conditions. Three groups of six animals each were injected with the antigen Bm91, saline, and adjuvant, respectively. Animals were immunized three times at 3-week intervals and a fourth time after six months. The anti-Bm91 antibody level, measured by ELISA, was monitored for 7 months and the reproductive performance of naturally infested R. (B.) microplus was determined. Bm91-immunized animals developed a strong immune response expressed by high anti-Bm91 levels remaining on high levels until the end of the study. Western blot analysis confirmed that Bm91 is immunogenic. Compared to control animals, the reproductive efficiency index and the egg viability were 6% and 8%, respectively, lower in the Bm91 group (P < 0.05). In conclusion, it was demonstrated that Bm91 induced a long-lasting immune response. However, the effect on the tick reproduction was not sufficient for an efficient tick control. Further studies under field conditions are warranted to enhance the effect on the tick reproduction by optimizing the immunization regimen, alone or in combination with other vaccine candidate antigens.
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Parizi LF, Githaka NW, Logullo C, Konnai S, Masuda A, Ohashi K, da Silva Vaz I. The quest for a universal vaccine against ticks: Cross-immunity insights. Vet J 2012; 194:158-65. [DOI: 10.1016/j.tvjl.2012.05.023] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 03/19/2012] [Accepted: 05/23/2012] [Indexed: 10/28/2022]
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Ben Said M, Galai Y, Mhadhbi M, Jedidi M, de la Fuente J, Darghouth MA. Molecular characterization of Bm86 gene orthologs from Hyalomma excavatum, Hyalomma dromedarii and Hyalomma marginatum marginatum and comparison with a vaccine candidate from Hyalomma scupense. Vet Parasitol 2012; 190:230-40. [DOI: 10.1016/j.vetpar.2012.05.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2012] [Revised: 05/10/2012] [Accepted: 05/15/2012] [Indexed: 11/16/2022]
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Ben Said M, Galai Y, Canales M, Nijhof AM, Mhadhbi M, Jedidi M, de la Fuente J, Darghouth MA. Hd86, the Bm86 tick protein ortholog in Hyalomma scupense (syn. H. detritum): expression in Pichia pastoris and analysis of nucleotides and amino acids sequences variations prior to vaccination trials. Vet Parasitol 2011; 183:215-23. [PMID: 21871736 DOI: 10.1016/j.vetpar.2011.07.049] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 07/07/2011] [Accepted: 07/27/2011] [Indexed: 11/16/2022]
Abstract
The genus Hyalomma includes the most frequent tick species infesting livestock in North Africa, one of these species, Hyalomma scupense (syn. H. detritum) is particularly important due to its role in the transmission of tropical theileriosis to cattle (Theileria annulata infection). We have cloned and characterized the orthologs of the Bm86 gene from H. scupense strains collected over Tunisia in 2006 and 2009. The recombinant protein rHd86 was expressed in Pichia pastoris for vaccination purpose using a transcript from the 2006 strain. The rHd86 was then purified from the yeast culture supernatant by a filtration and a size exclusion process. It was recognized by specific anti-Bm86 antisera. An important extent of inter-specific diversity ranging from 35 to 40% was recorded between Hd86 and Bm86/Bm95 proteins whilst a very limited level of intra-specific diversity (1.7%) occurred between the Hd86 vaccine candidate protein and its homologues from H. scupense strains collected in 2009. These results emphasise the need for assessing the efficacy against H. scupense and others important cattle Hyalomma species in Tunisia of our Hd86 vaccine candidate alongside with a Bm86 vaccine.
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Affiliation(s)
- Mourad Ben Said
- Laboratoire de Parasitologie Ecole Nationale de Médecine Vétérinaire, 2020 Sidi Thabet, Tunisia
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Bastos RG, Ueti MW, Knowles DP, Scoles GA. The Rhipicephalus (Boophilus) microplus Bm86 gene plays a critical role in the fitness of ticks fed on cattle during acute Babesia bovis infection. Parasit Vectors 2010; 3:111. [PMID: 21092112 PMCID: PMC2994843 DOI: 10.1186/1756-3305-3-111] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Accepted: 11/19/2010] [Indexed: 12/25/2022] Open
Abstract
Background Rhipicephalus (Boophilus) microplus is an economically important tick of cattle involved in the transmission of Babesia bovis, the etiological agent of bovine babesiosis. Commercial anti-tick vaccines based on the R. microplus Bm86 glycoprotein have shown some effect in controlling tick infestation; however their efficacy as a stand-alone solution for tick control has been questioned. Understanding the role of the Bm86 gene product in tick biology is critical to identifying additional methods to utilize Bm86 to reduce R. microplus infestation and babesia transmission. Additionally, the role played by Bm86 in R. microplus fitness during B. bovis infection is unknown. Results Here we describe in two independent experiments that RNA interference-mediated silencing of Bm86 decreased the fitness of R. microplus females fed on cattle during acute B. bovis infection. Notably, Bm86 silencing decreased the number and survival of engorged females, and decreased the weight of egg masses. However, gene silencing had no significant effect on the efficiency of transovarial transmission of B. bovis from surviving female ticks to their larval offspring. The results also show that Bm86 is expressed, in addition to gut cells, in larvae, nymphs, adult males and ovaries of partially engorged adult R. microplus females, and its expression was significantly down-regulated in ovaries of ticks fed on B. bovis-infected cattle. Conclusion The R. microplus Bm86 gene plays a critical role during tick feeding and after repletion during blood digestion in ticks fed on cattle during acute B. bovis infection. Therefore, the data indirectly support the rationale for using Bm86-based vaccines, perhaps in combination with acaricides, to control tick infestation particularly in B. bovis endemic areas.
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Affiliation(s)
- Reginaldo G Bastos
- Program in Vector-Borne Diseases, Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164-7040, USA.
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