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Parasites & vectors2013; 6(1); 306; doi: 10.1186/1756-3305-6-306

Amblyomma cajennense is an intrastadial biological vector of Theileria equi.

Abstract: The apicomplexan hemoprotozoan parasite Theileria equi is one of the etiologic agents causing equine piroplasmosis, a disease of equines that is endemic throughout large parts of the world. Before 2009 the United States had been considered to be free of this parasite. Occasional cases had occurred but there was no evidence for endemic vector-borne transmission in the U.S. until a 2009 outbreak in Texas in which Dermacentor variabilis and Amblyomma cajennense were implicated as vectors. Although D. variabilis has previously been shown to be a competent laboratory vector, studies suggested A. cajennense was not a competent transstadial vector, even though the presence of this tick species on horses in South American is epidemiologicaly correlated with higher a prevalence of infection. In this study we tested the transstadial and intrastadial vector competence of D. variabilis and A. cajennense for T. equi. Methods: A tick passaged T. equi strain from the Texas outbreak and ticks colonized from engorged females collected off horses on the outbreak ranch in Texas were used for these studies. Nymph or adult ticks were fed on infected horses and transmission fed on naïve horses. Infections were tracked with PCR and serology, dissected tick tissues were tested with PCR. Results: A. cajennense transmitted T. equi intrastadially when adult ticks acquired infection by feeding on an infected horse, and transmitted to a naïve host on subsequent reattachment and feeding. D. variabilis failed to transmit in the same experiment. Transstadial transmission was not successful for either tick species. PCR on DNA isolated from eggs of females that had fed on an infected horse suggests that there is no transovarial passage of this parasite by either tick species. Conclusions: This work confirms that ticks from the Texas population of A. cajennense are competent intrastadial vectors of T. equi. We propose that the most likely natural mode of transmission for this parasite/vector combination in the Texas outbreak would have been biological transmission resulting from adult male ticks moving between infected and uninfected horses. The intrastadial mode of transmission should be considered as one equally possible scenario whenever implicating vectors of T. equi.
Publication Date: 2013-10-23 PubMed ID: 24499587PubMed Central: PMC4028807DOI: 10.1186/1756-3305-6-306Google Scholar: Lookup
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  • Journal Article
  • Research Support
  • Non-U.S. Gov't
  • Research Support
  • U.S. Gov't
  • Non-P.H.S.

Summary

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The research article discusses a study conducted to test the capacity of two tick species in transmitting the Theileria equi parasite, a causative agent of equine piroplasmosis. The study revealed that the Amblyomma cajennense tick is a competent intrastadial vector of the parasite.

Research Context

  • The cause of concern in the study is Theileria equi, an apicomplexan hemoprotozoan parasite leading to equine piroplasmosis, a disease affecting horses.
  • Though the United States was considered free of this parasite until 2009, an outbreak in Texas revealed Dermacentor variabilis and Amblyomma cajennense ticks as potential vectors.
  • Previous studies have indicated D. variabilis as a competent laboratory vector. However, initial studies suggested A. cajennense may not be a competent transstadial vector, despite being linked with higher infection rates in South America.

Study Approach and Methodology

  • The researchers used a T. equi strain passed through ticks during the Texas outbreak and ticks cultivated from engorged females gathered from horses on the outbreak ranch for the tests.
  • They fed nymph or adult ticks on infected horses and then allowed them to feed on naïve horses. This was done to monitor the transmission of the parasite.
  • The presence of infections was tracked through Polymerase Chain Reaction (PCR) and serology (study of blood serums).

Findings of the Study

  • A. cajennense ticks acted as intrastadial vectors, successfully transmitting T. equi when the adult ticks fed on an infected horse, and transferred it to a naïve host upon subsequent reattachment and feeding.
  • In the same experiment, D. variabilis failed to transmit the parasite, and transstadial transmission was found unsuccessful in both tick species.
  • Further PCR tests on DNA isolated from the offspring of females that had fed on an infected host suggested that neither of the tick species passes this parasite through their eggs (transovarial transmission).

Conclusion

  • Findings provided validation that the Texas population of A. cajennense ticks could efficiently transmit T. equi on an intrastadial basis.
  • The authors propose that the most plausible explanation for the breakout in Texas was the biological transmission of the parasite via adult male ticks moving between infected and uninfected horses.
  • The study strongly affirms that the capability for intrastadial transmission should be viewed as an equally likely possibility for vectors of T. equi.

Cite This Article

APA
Scoles GA, Ueti MW. (2013). Amblyomma cajennense is an intrastadial biological vector of Theileria equi. Parasit Vectors, 6(1), 306. https://doi.org/10.1186/1756-3305-6-306

Publication

ISSN: 1756-3305
NlmUniqueID: 101462774
Country: England
Language: English
Volume: 6
Issue: 1
Pages: 306

Researcher Affiliations

Scoles, Glen A
  • USDA, ARS, Animal Disease Research Unit, 3003 ADBF, Washington State University, Pullman, WA 99164, USA. Scoles@vetmed.wsu.edu.
Ueti, Massaro W

    MeSH Terms

    • Animals
    • Disease Vectors
    • Female
    • Horse Diseases / parasitology
    • Horse Diseases / transmission
    • Horses
    • Ixodidae / parasitology
    • Male
    • Polymerase Chain Reaction
    • Texas
    • Theileria / genetics
    • Theileria / isolation & purification
    • Theileriasis / parasitology
    • Theileriasis / transmission

    References

    This article includes 30 references
    1. Friedhoff KT, Tenter AM, Müller I. Haemoparasites of equines: impact on international trade of horses.. Rev Sci Tech 1990 Dec;9(4):1187-94.
      pubmed: 2132711
    2. Zapf F, Schein E. New findings in the development of Babesia (Theileria) equi (Laveran, 1901) in the salivary glands of the vector ticks, Hyalomma species.. Parasitol Res 1994;80(7):543-8.
      doi: 10.1007/BF00933000pubmed: 7855118google scholar: lookup
    3. Zapf F, Schein E. The development of Babesia (Theileria) equi (Laveran, 1901) in the gut and the haemolymph of the vector ticks, Hyalomma species.. Parasitol Res 1994;80(4):297-302.
      doi: 10.1007/BF02351869pubmed: 8073015google scholar: lookup
    4. Ueti MW, Palmer GH, Scoles GA, Kappmeyer LS, Knowles DP. Persistently infected horses are reservoirs for intrastadial tick-borne transmission of the apicomplexan parasite Babesia equi.. Infect Immun 2008 Aug;76(8):3525-9.
      doi: 10.1128/IAI.00251-08pmc: PMC2493223pubmed: 18490466google scholar: lookup
    5. Ueti MW, Palmer GH, Kappmeyer LS, Statdfield M, Scoles GA, Knowles DP. Ability of the vector tick Boophilus microplus to acquire and transmit Babesia equi following feeding on chronically infected horses with low-level parasitemia.. J Clin Microbiol 2005 Aug;43(8):3755-9.
    6. Gerstenberg C, Allen WR, Phipps LP. The Mechanical Transmission of Babesia equi infection in a British herd of horses. 1998; p. 100.
    7. Scoles GA, Hutcheson HJ, Schlater JL, Hennager SG, Pelzel AM, Knowles DP. Equine piroplasmosis associated with Amblyomma cajennense Ticks, Texas, USA.. Emerg Infect Dis 2011 Oct;17(10):1903-5.
      doi: 10.3201/eid1710.101182pmc: PMC3310643pubmed: 22000367google scholar: lookup
    8. OIE. Manual of diagnostic tests and vaccines for terrestrial animals, 7th edition. 2012.
    9. Short MA, Clark CK, Harvey JW, Wenzlow N, Hawkins IK, Allred DR, Knowles DP, Corn JL, Grause JF, Hennager SG, Kitchen DL, Traub-Dargatz JL. Outbreak of equine piroplasmosis in Florida.. J Am Vet Med Assoc 2012 Mar 1;240(5):588-95.
      doi: 10.2460/javma.240.5.588pubmed: 22332629google scholar: lookup
    10. Stiller D, Coan ME. Recent developments in elucidating tick vector relationships for anaplasmosis and equine piroplasmosis.. Vet Parasitol 1995 Mar;57(1-3):97-108.
      pubmed: 7597797doi: 10.1016/0304-4017(94)03114-cgoogle scholar: lookup
    11. Stiller D, Goff WL, Johnson LW, Knowles DP. Dermacentor variabilis and boophilus microplus (Acari: Ixodidae): experimental vectors of Babesia equi to equids.. J Med Entomol 2002 Jul;39(4):667-70.
      doi: 10.1603/0022-2585-39.4.667pubmed: 12144301google scholar: lookup
    12. Kerber CE, Labruna MB, Ferreira F, De Waal DT, Knowles DP, Gennari SM. Prevalence of equine Piroplasmosis and its association with tick infestation in the State of São Paulo, Brazil.. Rev Bras Parasitol Vet 2009 Oct-Dec;18(4):1-8.
      doi: 10.4322/rbpv.01804001pubmed: 20040201google scholar: lookup
    13. Pfeifer Barbosa I, Böse R, Peymann B, Friedhoff KT. Epidemiological aspects of equine babesioses in a herd of horses in Brazil.. Vet Parasitol 1995 May;58(1-2):1-8.
      pubmed: 7676590doi: 10.1016/0304-4017(94)00704-ggoogle scholar: lookup
    14. Ribeiro MF, da Silveira JA, Bastos CV. Failure of the Amblyomma cajennense nymph to become infected by Theileria equi after feeding on acute or chronically infected horses.. Exp Parasitol 2011 Aug;128(4):324-7.
      doi: 10.1016/j.exppara.2011.03.016pubmed: 21501609google scholar: lookup
    15. Hall CM, Busch JD, Scoles GA, Palma-Cagle KA, Ueti MW, Kappmeyer LS, Wagner DM. Genetic characterization of Theileria equi infecting horses in North America: evidence for a limited source of U.S. introductions.. Parasit Vectors 2013 Feb 11;6:35.
      doi: 10.1186/1756-3305-6-35pmc: PMC3606381pubmed: 23399005google scholar: lookup
    16. Ueti MW, Palmer GH, Kappmeyer LS, Scoles GA, Knowles DP. Expression of equi merozoite antigen 2 during development of Babesia equi in the midgut and salivary gland of the vector tick Boophilus microplus.. J Clin Microbiol 2003 Dec;41(12):5803-9.
    17. Knowles DP, Kappmeyer LS, Perryman LE. Genetic and biochemical analysis of erythrocyte-stage surface antigens belonging to a family of highly conserved proteins of Babesia equi and Theileria species.. Mol Biochem Parasitol 1997 Dec 1;90(1):69-79.
      doi: 10.1016/S0166-6851(97)00150-3pubmed: 9497033google scholar: lookup
    18. Battsetseg B, Lucero S, Xuan X, Claveria F, Byambaa B, Battur B, Boldbaatar D, Batsukh Z, Khaliunaa T, Battsetseg G, Igarashi I, Nagasawa H, Fujisaki K. Detection of equine Babesia spp. gene fragments in Dermacentor nuttalli Olenev 1929 infesting mongolian horses, and their amplification in egg and larval progenies.. J Vet Med Sci 2002 Aug;64(8):727-30.
      doi: 10.1292/jvms.64.727pubmed: 12237521google scholar: lookup
    19. Labruna MB, Kerber CE, Ferreira F, Faccini JL, De Waal DT, Gennari SM. Risk factors to tick infestations and their occurrence on horses in the state of São Paulo, Brazil.. Vet Parasitol 2001 May 9;97(1):1-14.
      doi: 10.1016/S0304-4017(01)00387-9pubmed: 11337122google scholar: lookup
    20. Abramov IV. A new type of transmission by vector ticks of the causal agent of nuttalliasis of horses (Nuttallia. equi, Laveran, 1901). Veterinariya 1955;6(8):43–45.
    21. Budnik VS. New data on the mechanism of transmission of the causal agent of nuttalliasîs of horses by the tick Dermacentor marginatus Sulz. Veterinariya 1955;6(8):36–43.
    22. Kocan KM, Stiller D, Goff WL, Claypool PL, Edwards W, Ewing SA, McGuire TC, Hair JA, Barron SJ. Development of Anaplasma marginale in male Dermacentor andersoni transferred from parasitemic to susceptible cattle.. Am J Vet Res 1992 Apr;53(4):499-507.
      pubmed: 1586018
    23. Kocan KM, Goff WL, Stiller D, Claypool PL, Edwards W, Ewing SA, Hair JA, Barron SJ. Persistence of Anaplasma marginale (Rickettsiales: Anaplasmataceae) in male Dermacentor andersoni (Acari: Ixodidae) transferred successively from infected to susceptible calves.. J Med Entomol 1992 Jul;29(4):657-68.
      pubmed: 1495076doi: 10.1093/jmedent/29.4.657google scholar: lookup
    24. Zaugg JL, Stiller D, Coan ME, Lincoln SD. Transmission of Anaplasma marginale Theiler by males of Dermacentor andersoni Stiles fed on an Idaho field-infected, chronic carrier cow.. Am J Vet Res 1986 Oct;47(10):2269-71.
      pubmed: 3777655
    25. Pinter A, Labruna MB, Faccini JL. The sex ratio of Amblyomma cajennense (Acari: Ixodidae) with notes on the male feeding period in the laboratory.. Vet Parasitol 2002 Apr 19;105(1):79-88.
      doi: 10.1016/S0304-4017(01)00650-1pubmed: 11879968google scholar: lookup
    26. Sonenshine DE. Biology of ticks, Volume 1. 1991.
    27. Little SE, Hostetler J, Kocan KM. Movement of Rhipicephalus sanguineus adults between co-housed dogs during active feeding.. Vet Parasitol 2007 Nov 30;150(1-2):139-45.
      pubmed: 17904292doi: 10.1016/j.vetpar.2007.08.029google scholar: lookup
    28. Lysyk TJ. Movement of male Dermacentor andersoni (Acari: Ixodidae) among cattle.. J Med Entomol 2013 Sep;50(5):977-85.
      doi: 10.1603/ME13012pubmed: 24180101google scholar: lookup
    29. Lopes CM, Leite RC, Labruna MB, de Oliveira PR, Borges LM, Rodrigues ZB, de Carvalho HA, de Freitas CM, Vieira Júnior CR. Host specificity of Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae) with comments on the drop-off rhythm.. Mem Inst Oswaldo Cruz 1998 May-Jun;93(3):347-51.
    30. Fraser AF. The behaviour and welfare of the horse, 2nd Edition. 2010.

    Citations

    This article has been cited 7 times.
    1. Onzere CK, Fry LM, Bishop RP, Silva MG, Bastos RG, Knowles DP, Suarez CE. Theileria equi claudin like apicomplexan microneme protein contains neutralization-sensitive epitopes and interacts with components of the equine erythrocyte membrane skeleton.. Sci Rep 2021 Apr 29;11(1):9301.
      doi: 10.1038/s41598-021-88902-4pubmed: 33927329google scholar: lookup
    2. Dinkel KD, Herndon DR, Noh SM, Lahmers KK, Todd SM, Ueti MW, Scoles GA, Mason KL, Fry LM. A U.S. isolate of Theileria orientalis, Ikeda genotype, is transmitted to cattle by the invasive Asian longhorned tick, Haemaphysalis longicornis.. Parasit Vectors 2021 Mar 16;14(1):157.
      doi: 10.1186/s13071-021-04659-9pubmed: 33726815google scholar: lookup
    3. Quadros DG, Johnson TL, Whitney TR, Oliver JD, Oliva Chávez AS. Plant-Derived Natural Compounds for Tick Pest Control in Livestock and Wildlife: Pragmatism or Utopia?. Insects 2020 Aug 1;11(8).
      doi: 10.3390/insects11080490pubmed: 32752256google scholar: lookup
    4. Onyiche TE, Suganuma K, Igarashi I, Yokoyama N, Xuan X, Thekisoe O. A Review on Equine Piroplasmosis: Epidemiology, Vector Ecology, Risk Factors, Host Immunity, Diagnosis and Control.. Int J Environ Res Public Health 2019 May 16;16(10).
      doi: 10.3390/ijerph16101736pubmed: 31100920google scholar: lookup
    5. Lobanov VA, Peckle M, Massard CL, Brad Scandrett W, Gajadhar AA. Development and validation of a duplex real-time PCR assay for the diagnosis of equine piroplasmosis.. Parasit Vectors 2018 Mar 2;11(1):125.
      doi: 10.1186/s13071-018-2751-6pubmed: 29499748google scholar: lookup
    6. Gondard M, Cabezas-Cruz A, Charles RA, Vayssier-Taussat M, Albina E, Moutailler S. Ticks and Tick-Borne Pathogens of the Caribbean: Current Understanding and Future Directions for More Comprehensive Surveillance.. Front Cell Infect Microbiol 2017;7:490.
      doi: 10.3389/fcimb.2017.00490pubmed: 29238699google scholar: lookup
    7. Düttmann C, Flores B, Kadoch Z N, Bermúdez C S. Hard ticks (Acari: Ixodidae) of livestock in Nicaragua, with notes about distribution.. Exp Appl Acarol 2016 Sep;70(1):125-35.
      doi: 10.1007/s10493-016-0059-9pubmed: 27392740google scholar: lookup