FREE SHIPPING over $40
OVER 10000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
Pathogens (Basel, Switzerland)2023; 12(3); 453; doi: 10.3390/pathogens12030453

Tulathromycin and Diclazuril Lack Efficacy against Theileria haneyi, but Tulathromycin Is Not Associated with Adverse Clinical Effects in Six Treated Adult Horses.

Abstract: Equine theileriosis, caused by and , leads to anemia, exercise intolerance, and occasionally, death. Theileriosis-free countries prohibit the importation of infected horses, resulting in significant costs for the equine industry. Imidocarb dipropionate is the only treatment for in the United States, but lacks efficacy against . The goal of this study was to assess the in vivo efficacy of tulathromycin and diclazuril against . Fourteen -infected horses were utilized. Six were treated with eight weekly 2.5 mg/kg doses of tulathromycin. Three were treated daily for eight weeks with 2.5 mg/kg diclazuril. Three were pre-treated with 0.5 mg/kg diclazuril daily for one month to determine whether low-dose diclazuril prevents infection. Following infection, the dose was increased to 2.5 mg/kg for eight weeks. Two infected horses remained untreated as controls. The horses were assessed via nested PCR, physical exams, complete blood counts, serum chemistry panels, and cytology. Tulathromycin and diclazuril failed to clear and the treated and control groups exhibited similar parasitemia and packed cell volume declines. To obtain additional safety data on tulathromycin use in adult horses, necropsy and histopathology were performed on tulathromycin-treated horses. No significant lesions were detected.
Get Full Text
Publication Date: 2023-03-14 PubMed ID: 36986375PubMed Central: PMC10055745DOI: 10.3390/pathogens12030453Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
LinkedInCopy
  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research article focuses on understanding the effectiveness of Tulathromycin and Diclazuril in treating an infections parasitic disease in horses, known as Equine theileriosis. Despite administered treatments, the research found that these drugs were unable to eradicate the parasitic infection in the horses.

Objective of the Study

  • The primary goal of this research is to explore the efficacy of the Tulathromycin and Diclazuril drugs against Equine theileriosis, specifically caused by the parasite Theileria haneyi.
  • The study also aims to determine the potential negative effects of Tulathromycin on adult horses.

Methodology of the Research

  • A total of 14 horses infected with Theileria haneyi were used in the experiment.
  • These horses were split into different groups, where different dosages and combinations of Tulathromycin and Diclazuril were administered.
  • A control group consisting of two infected horses was also set, receiving no treatment for relative comparison with those receiving treatments.
  • Assessments were made using nested PCR, physical examinations, complete blood counts, serum chemistry panels, and cytology.

Results from the Study

  • Results showed that both Tulathromycin and Diclazuril were not successful in eliminating Theileria haneyi from the infected horses.
  • The levels of parasitemia (presence of parasites in the blood) and declines in packed cell volume were similar in both the treated horses as well as the control group.
  • As for the potential negative effects of Tulathromycin, the study did not find any significant lesions or harmful effects in the Tulathromycin-treated horses. Necropsies and histopathology were performed to gather this data.

Cite This Article

APA
Onzere CK, Hulbert M, Sears KP, Williams LBA, Fry LM. (2023). Tulathromycin and Diclazuril Lack Efficacy against Theileria haneyi, but Tulathromycin Is Not Associated with Adverse Clinical Effects in Six Treated Adult Horses. Pathogens, 12(3), 453. https://doi.org/10.3390/pathogens12030453

Publication

Pathogens (Basel, Switzerland)
ISSN: 2076-0817
NlmUniqueID: 101596317
Country: Switzerland
Language: English
Volume: 12
Issue: 3
PII: 453

Researcher Affiliations

Onzere, Cynthia K
  • Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA.
Hulbert, Morgan
  • College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Sears, Kelly P
  • Department of Clinical Science, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA.
Williams, Laura B A
  • Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA.
Fry, Lindsay M
  • Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA.
  • Animal Disease Research Unit, USDA-ARS, Pullman, WA 99164, USA.

Grant Funding

  • 2090-32000-044-000-D / Agricultural Research Service - Pacific West Area
  • ARS 59-3022-1-003 / USDA ARS NBAF AGREEMENT

Conflict of Interest Statement

The authors declare no conflict of interest.

References

This article includes 43 references
  1. Knowles DP, Kappmeyer LS, Haney D, Herndon DR, Fry LM, Munro JB, Sears K, Ueti MW, Wise LN, Silva M, Schneider DA, Grause J, White SN, Tretina K, Bishop RP, Odongo DO, Pelzel-McCluskey AM, Scoles GA, Mealey RH, Silva JC. Discovery of a novel species, Theileria haneyi n. sp., infective to equids, highlights exceptional genomic diversity within the genus Theileria: implications for apicomplexan parasite surveillance.. Int J Parasitol 2018 Aug;48(9-10):679-690.
    doi: 10.1016/j.ijpara.2018.03.010pubmed: 29885436google scholar: lookup
  2. Wise LN, Kappmeyer LS, Mealey RH, Knowles DP. Review of equine piroplasmosis.. J Vet Intern Med 2013 Nov-Dec;27(6):1334-46.
    doi: 10.1111/jvim.12168pubmed: 24033559google scholar: lookup
  3. Wise LN, Pelzel-McCluskey AM, Mealey RH, Knowles DP. Equine piroplasmosis.. Vet Clin North Am Equine Pract 2014 Dec;30(3):677-93.
    doi: 10.1016/j.cveq.2014.08.008pubmed: 25300637google scholar: lookup
  4. Bishop RP, Kappmeyer LS, Onzere CK, Odongo DO, Githaka N, Sears KP, Knowles DP, Fry LM. Equid infective Theileria cluster in distinct 18S rRNA gene clades comprising multiple taxa with unusually broad mammalian host ranges.. Parasit Vectors 2020 May 19;13(1):261.
    doi: 10.1186/s13071-020-04131-0pmc: PMC7236219pubmed: 32430015google scholar: lookup
  5. O'Connor RM, Nepveux V FJ, Abenoja J, Bowden G, Reis P, Beaushaw J, Bone Relat RM, Driskell I, Gimenez F, Riggs MW, Schaefer DA, Schmidt EW, Lin Z, Distel DL, Clardy J, Ramadhar TR, Allred DR, Fritz HM, Rathod P, Chery L, White J. A symbiotic bacterium of shipworms produces a compound with broad spectrum anti-apicomplexan activity.. PLoS Pathog 2020 May;16(5):e1008600.
    doi: 10.1371/journal.ppat.1008600pmc: PMC7274485pubmed: 32453775google scholar: lookup
  6. Singh B, Banerjee DP, Gautam OP, Gupta RKP. Clinicopathological changes in splenectomised donkeys infected with Babesia equi. Indian J. Parasitol. 1980;4:77–80.
  7. Guimarães A, Lima J, Tafuri W, Ribeiro M, Sciavicco C, Botelho A. Clinical and histopathological aspects of splenectomized foals infected by babesia equi. J. Equine Vet. Sci. 1997;17:211–216.
    doi: 10.1016/S0737-0806(97)80563-1google scholar: lookup
  8. Kuttler KL, Gipson CA, Goff WL, Johnson LW. Experimental Babesia equi infection in mature horses.. Am J Vet Res 1986 Aug;47(8):1668-70.
    pubmed: 3530065
  9. Sears KP, Kappmeyer LS, Wise LN, Silva M, Ueti MW, White S, Reif KE, Knowles DP. Infection dynamics of Theileria equi and Theileria haneyi, a newly discovered apicomplexan of the horse.. Vet Parasitol 2019 Jul;271:68-75.
    doi: 10.1016/j.vetpar.2019.06.009pubmed: 31303207google scholar: lookup
  10. Sears KP, Knowles DP, Fry LM. Clinical Progression of Theileria haneyi in Splenectomized Horses Reveals Decreased Virulence Compared to Theileria equi.. Pathogens 2022 Feb 16;11(2).
    doi: 10.3390/pathogens11020254pmc: PMC8879895pubmed: 35215197google scholar: lookup
  11. Sears K, Knowles D, Dinkel K, Mshelia PW, Onzere C, Silva M, Fry L. Imidocarb Dipropionate Lacks Efficacy against Theileria haneyi and Fails to Consistently Clear Theileria equi in Horses Co-Infected with T. haneyi.. Pathogens 2020 Dec 10;9(12).
    doi: 10.3390/pathogens9121035pmc: PMC7764667pubmed: 33321715google scholar: lookup
  12. Grause JF, Ueti MW, Nelson JT, Knowles DP, Kappmeyer LS, Bunn TO. Efficacy of imidocarb dipropionate in eliminating Theileria equi from experimentally infected horses.. Vet J 2013 Jun;196(3):541-6.
    doi: 10.1016/j.tvjl.2012.10.025pubmed: 23199699google scholar: lookup
  13. Kuttler KL, Zaugg JL, Gipson CA. Imidocarb and parvaquone in the treatment of piroplasmosis (Babesia equi) in equids.. Am J Vet Res 1987 Nov;48(11):1613-6.
    pubmed: 3434908
  14. Ueti MW, Mealey RH, Kappmeyer LS, White SN, Kumpula-McWhirter N, Pelzel AM, Grause JF, Bunn TO, Schwartz A, Traub-Dargatz JL, Hendrickson A, Espy B, Guthrie AJ, Fowler WK, Knowles DP. Re-emergence of the apicomplexan Theileria equi in the United States: elimination of persistent infection and transmission risk.. PLoS One 2012;7(9):e44713.
    doi: 10.1371/journal.pone.0044713pmc: PMC3435266pubmed: 22970295google scholar: lookup
  15. Leclere M, Magdesian KG, Cole CA, Szabo NJ, Ruby RE, Rhodes DM, Edman J, Vale A, Wilson WD, Tell LA. Pharmacokinetics and preliminary safety evaluation of azithromycin in adult horses.. J Vet Pharmacol Ther 2012 Dec;35(6):541-9.
    doi: 10.1111/j.1365-2885.2011.01351.xpubmed: 22136612google scholar: lookup
  16. Villarino N, Brown SA, Martín-Jiménez T. The role of the macrolide tulathromycin in veterinary medicine.. Vet J 2013 Nov;198(2):352-7.
    doi: 10.1016/j.tvjl.2013.07.032pubmed: 24268476google scholar: lookup
  17. Villarino N, Denny JE, Schmidt NW. Antimalarial activity of tulathromycin in a murine model of malaria.. Antimicrob Agents Chemother 2015;59(6):3672-4.
    doi: 10.1128/AAC.02858-14pmc: PMC4432142pubmed: 25870067google scholar: lookup
  18. Silva MG, Villarino NF, Knowles DP, Suarez CE. Assessment of Draxxin(®) (tulathromycin) as an inhibitor of in vitro growth of Babesia bovis, Babesia bigemina and Theileria equi.. Int J Parasitol Drugs Drug Resist 2018 Aug;8(2):265-270.
    doi: 10.1016/j.ijpddr.2018.04.004pmc: PMC6039354pubmed: 29689532google scholar: lookup
  19. Rutenberg D, Venner M, Giguère S. Efficacy of Tulathromycin for the Treatment of Foals with Mild to Moderate Bronchopneumonia.. J Vet Intern Med 2017 May;31(3):901-906.
    doi: 10.1111/jvim.14717pmc: PMC5435035pubmed: 28421633google scholar: lookup
  20. Mercer MA. Macrolide Use in Animals. Merck Veterinary Manual 2022. 2023.
  21. Båverud V, Franklin A, Gunnarsson A, Gustafsson A, Hellander-Edman A. Clostridium difficile associated with acute colitis in mares when their foals are treated with erythromycin and rifampicin for Rhodococcus equi pneumonia.. Equine Vet J 1998 Nov;30(6):482-8.
    doi: 10.1111/j.2042-3306.1998.tb04523.xpubmed: 9844966google scholar: lookup
  22. Gustafsson A, Båverud V, Gunnarsson A, Rantzien MH, Lindholm A, Franklin A. The association of erythromycin ethylsuccinate with acute colitis in horses in Sweden.. Equine Vet J 1997 Jul;29(4):314-8.
    doi: 10.1111/j.2042-3306.1997.tb03129.xpubmed: 15338913google scholar: lookup
  23. Leventhal HR, McKenzie HC, Estell K, Council-Troche M, Davis JL. Pharmacokinetics and pulmonary distribution of Draxxin(®) (tulathromycin) in healthy adult horses.. J Vet Pharmacol Ther 2021 Sep;44(5):714-723.
    doi: 10.1111/jvp.12968pubmed: 33719056google scholar: lookup
  24. Stock ML, Elazab ST, Hsu WH. Review of triazine antiprotozoal drugs used in veterinary medicine.. J Vet Pharmacol Ther 2018 Apr;41(2):184-194.
    doi: 10.1111/jvp.12450pubmed: 28833212google scholar: lookup
  25. Dirikolu L, Karpiesiuk W, Lehner AF, Hughes C, Woods WE, Harkins JD, Boyles J, Atkinson A, Granstrom DE, Tobin T. New therapeutic approaches for equine protozoal myeloencephalitis: pharmacokinetics of diclazuril sodium salts in horses.. Vet Ther 2006 Spring;7(1):52-63, 72.
    pubmed: 16598684
  26. Dirikolu L, Lehner F, Nattrass C, Bentz BG, Woods WE, Carter WG, Karpiesiuk W, Jacobs J, Boyles J, Harkins JD, Granstrom DE, Tobin T. Diclazuril in the horse: its identification and detection and preliminary pharmacokinetics.. J Vet Pharmacol Ther 1999 Dec;22(6):374-9.
    doi: 10.1046/j.1365-2885.1999.00232.xpubmed: 10651466google scholar: lookup
  27. Hunyadi L, Papich MG, Pusterla N. Pharmacokinetics of a low dose and FDA-labeled dose of diclazuril administered orally as a pelleted topdressing in adult horses.. J Vet Pharmacol Ther 2015 Jun;38(3):243-8.
    doi: 10.1111/jvp.12176pubmed: 25329774google scholar: lookup
  28. Pusterla N, Packham A, Mackie S, Kass PH, Hunyadi L, Conrad PA. Daily feeding of diclazuril top dress pellets in foals reduces seroconversion to Sarcocystis neurona.. Vet J 2015 Nov;206(2):236-8.
    doi: 10.1016/j.tvjl.2015.07.018pubmed: 26346260google scholar: lookup
  29. Wise LN, Ueti MW, Kappmeyer LS, Hines MT, White SN, Davis W, Knowles DP. In vitro activity of ponazuril against Theileria equi.. Vet Parasitol 2012 Apr 30;185(2-4):282-5.
    doi: 10.1016/j.vetpar.2011.10.036pubmed: 22130334google scholar: lookup
  30. Gajadhar AA, Marquardt WC, Hall R, Gunderson J, Ariztia-Carmona EV, Sogin ML. Ribosomal RNA sequences of Sarcocystis muris, Theileria annulata and Crypthecodinium cohnii reveal evolutionary relationships among apicomplexans, dinoflagellates, and ciliates.. Mol Biochem Parasitol 1991 Mar;45(1):147-54.
    doi: 10.1016/0166-6851(91)90036-6pubmed: 1904987google scholar: lookup
  31. Hostetter JM, Uzal FA. Gastrointestinal biopsy in the horse: overview of collection, interpretation, and applications.. J Vet Diagn Invest 2022 May;34(3):376-388.
    doi: 10.1177/10406387221085584pmc: PMC9254066pubmed: 35354416google scholar: lookup
  32. Rocchigiani G, Ricci E, Navarro MA, Samol MA, Uzal FA. Leukocyte numbers and intestinal mucosal morphometrics in horses with no clinical intestinal disease.. J Vet Diagn Invest 2022 May;34(3):389-395.
    doi: 10.1177/10406387211031944pmc: PMC9254073pubmed: 34293980google scholar: lookup
  33. Chaffin MK, Fuenteabla IC, Schumacher J, Welch RD, Edwards JF. Idiopathic muscular hypertrophy of the equine small intestine: 11 cases (1980-1991).. Equine Vet J 1992 Sep;24(5):372-8.
    doi: 10.1111/j.2042-3306.1992.tb02858.xpubmed: 1396511google scholar: lookup
  34. Navas De Solís C, Biscoe EW, Lund CM, Labbe K, Muñoz J, Farnsworth K. Imaging diagnosis--muscular hypertrophy of the small intestine and pseudodiverticula in a horse.. Vet Radiol Ultrasound 2015 Mar-Apr;56(2):E13-6.
    doi: 10.1111/vru.12133pubmed: 24382217google scholar: lookup
  35. Hostettler I, Müller J, Hemphill A. In Vitro Screening of the Open-Source Medicines for Malaria Venture Malaria Box Reveals Novel Compounds with Profound Activities against Theileria annulata Schizonts.. Antimicrob Agents Chemother 2016 Jun;60(6):3301-8.
    doi: 10.1128/AAC.02801-15pmc: PMC4879373pubmed: 26976863google scholar: lookup
  36. Nugraha AB, Tuvshintulga B, Guswanto A, Tayebwa DS, Rizk MA, Gantuya S, El-Saber Batiha G, Beshbishy AM, Sivakumar T, Yokoyama N, Igarashi I. Screening the Medicines for Malaria Venture Pathogen Box against piroplasm parasites.. Int J Parasitol Drugs Drug Resist 2019 Aug;10:84-90.
    doi: 10.1016/j.ijpddr.2019.06.004pmc: PMC6603297pubmed: 31254719google scholar: lookup
  37. Nyagwange J, Awino E, Tijhaar E, Svitek N, Pelle R, Nene V. Leveraging the Medicines for Malaria Venture malaria and pathogen boxes to discover chemical inhibitors of East Coast fever.. Int J Parasitol Drugs Drug Resist 2019 Apr;9:80-86.
    doi: 10.1016/j.ijpddr.2019.01.002pmc: PMC6376154pubmed: 30771616google scholar: lookup
  38. Rizk MA, Baghdadi HB, El-Sayed SAE, Eltaysh R, Igarashi I. Repurposing of the Malaria Box for Babesia microti in mice identifies novel active scaffolds against piroplasmosis.. Parasit Vectors 2022 Sep 19;15(1):329.
    doi: 10.1186/s13071-022-05430-4pmc: PMC9487043pubmed: 36123705google scholar: lookup
  39. Rizk MA, El-Sayed SAE, El-Khodery S, Yokoyama N, Igarashi I. Discovering the in vitro potent inhibitors against Babesia and Theileria parasites by repurposing the Malaria Box: A review.. Vet Parasitol 2019 Oct;274:108895.
    doi: 10.1016/j.vetpar.2019.07.003pubmed: 31494399google scholar: lookup
  40. Rizk MA, El-Sayed SAE, Eltaysh R, Igarashi I. MMV020275 and MMV020490, promising compounds from malaria box for the treatment of equine piroplasmosis.. Ticks Tick Borne Dis 2022 Mar;13(2):101904.
    doi: 10.1016/j.ttbdis.2022.101904pubmed: 35091295google scholar: lookup
  41. Hines SA, Ramsay JD, Kappmeyer LS, Lau AO, Ojo KK, Van Voorhis WC, Knowles DP, Mealey RH. Theileria equi isolates vary in susceptibility to imidocarb dipropionate but demonstrate uniform in vitro susceptibility to a bumped kinase inhibitor.. Parasit Vectors 2015 Jan 20;8:33.
    doi: 10.1186/s13071-014-0611-6pmc: PMC4311422pubmed: 25600252google scholar: lookup
  42. Bowden GD, Reis PM, Rogers MB, Bone Relat RM, Brayton KA, Wilson SK, Di Genova BM, Knoll LJ, Nepveux V FJ, Tai AK, Ramadhar TR, Clardy J, O'Connor RM. A conserved coccidian gene is involved in Toxoplasma sensitivity to the anti-apicomplexan compound, tartrolon E.. Int J Parasitol Drugs Drug Resist 2020 Dec;14:1-7.
    doi: 10.1016/j.ijpddr.2020.07.003pmc: PMC7394737pubmed: 32738587google scholar: lookup
  43. Gimenez F, Hines SA, Evanoff R, Ojo KK, Van Voorhis WC, Maly DJ, Vidadala RSR, Mealey RH. In vitro growth inhibition of Theileria equi by bumped kinase inhibitors.. Vet Parasitol 2018 Feb 15;251:90-94.
    doi: 10.1016/j.vetpar.2017.12.024pmc: PMC5959018pubmed: 29426483google scholar: lookup

Citations

This article has been cited 5 times.
  1. Gupta KK, Gupta N, Kumar S, Srivastava M, Kumar P. Equine piroplasmosis: an emerging tick-borne threat to equine health. Trop Anim Health Prod 2026 Jan 5;58(1):29.
    doi: 10.1007/s11250-025-04829-2pubmed: 41489672google scholar: lookup
  2. Poh KC, Oyen K, Onzere CK, Kappmeyer LS, Bastos RG. Haemaphysalis longicornis ticks are unable to transstadially transmit Theileria haneyi to horses. Front Vet Sci 2025;12:1572944.
    doi: 10.3389/fvets.2025.1572944pubmed: 40241805google scholar: lookup
  3. Fernandes TA, Paulino PG, Dos Santos Juliano D, Rabello CA, de Oliveira NVB, de Souza Santana M, Peckle M, Massard CL, da Costa Angelo I, Jacob JCF, Santos HA. Epidemiology and genetic diversity of Theileria equi and Babesia caballi in draft horses in the Distrito Federal, Brazil. Trop Anim Health Prod 2025 Feb 19;57(2):72.
    doi: 10.1007/s11250-025-04321-xpubmed: 39969660google scholar: lookup
  4. Mendoza FJ, Pérez-Écija A, Kappmeyer LS, Suarez CE, Bastos RG. New insights in the diagnosis and treatment of equine piroplasmosis: pitfalls, idiosyncrasies, and myths. Front Vet Sci 2024;11:1459989.
    doi: 10.3389/fvets.2024.1459989pubmed: 39205808google scholar: lookup
  5. Onzere CK, Hassan A, Sears K, Kappmeyer LS, Villarino NF, Fry LM, Bastos RG. Transient efficacy of buparvaquone against Theileria haneyi in chronically infected horses. Parasit Vectors 2024 Aug 12;17(1):337.
    doi: 10.1186/s13071-024-06397-0pubmed: 39129000google scholar: lookup
Subscribe to our newsletter
Join 99,780 horse owners like you who receive our email updates on horse health and nutrition.