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. 2024 Mar 10;17(1):120.
doi: 10.1186/s13071-024-06212-w.

Enzootic stability of tick fever in Holstein calves grazing in a tropical region, subjected to strategic cattle tick control with fluralaner

Dina Maria Beltran Zapa  1 , Lidia Mendes de Aquino  1 , Luiz Felipe Monteiro Couto  1 , Luciana Maffini Heller  1 , Igor Maciel Lopes de Morais  1 , Vanessa Ferreira Salvador  1 , Luccas Lourenzzo Lima Lins Leal  1 , Artur Siqueira Nunes Trindade  1 , Warley Vieira de Freitas Paula  2 , Nicolas Jalowitzki de Lima  2 , Lorena Lopes Ferreira  3 , Daniel de Castro Rodrigues  1   4 , Tom Strydom  5 , Siddhartha Torres  6 , Vando Edésio Soares  7 , Caio Marcio de Oliveira Monteiro  1   8 , Felipe da Silva Krawczak  2 , Welber Daniel Zanetti Lopes  9   10
Affiliations

Enzootic stability of tick fever in Holstein calves grazing in a tropical region, subjected to strategic cattle tick control with fluralaner

Dina Maria Beltran Zapa et al. Parasit Vectors. .

Abstract

Background: In 2022, fluralaner was launched on the market for use in the control of the cattle tick Rhipicephalus microplus after showing 100% efficacy in registration trials against the causative agents of cattle tick fever (TFAs). The aim of the present study was to determine whether a strategic control regimen against R. microplus using fluralaner (FLU) in Holstein calves grazing in a tropical region would alter the enzootic stability status of cattle tick fever, triggering outbreaks in these animals up to 22 months age.

Methods: In this study, a group of calves treated with FLU was compared with a control group treated with the regimen currently being used on the farm, which consisted of the fipronil + fluazuron formulation (FIFLUA). In the first experiment, the efficacy of the FIFLUA pour-on formulation was evaluated in a field study. In the second experiment, which lasted 550 days, two experimental groups (n = 30/group) of Holstein calves naturally infested with R. microplus were analyzed. Calves aged 4 to 10 months received either a specific treatment regimen with FLU (experimental group) or FIFLUA (control group). During this period, tick counts, animal weight measurement, feces collection (to determine eggs and oocysts per gram of feces), tick fever monitoring, blood smears (to ascertain enzootic stability of the herd), PCR testing for TFAs and serology (indirect enzyme-linked immunosorbent assay [iELISA]) were performed. All calves were evaluated for signs of tick fever between ages 11 and 22 months.

Results: FIFLUA showed an acaricidal efficacy of > 90% from post-treatment days 14 to 35. Regarding treatments against the TFAs, the average number of treatments was similar between groups, but animals treated with FLU had a smaller reduction in packed cell volume on some of the evaluation dates of the second and third treatment against TFAs. In calves aged 10 months in the FLU group, B. bovis was not detected by PCR (0/15 samples), 40% of the samples had antibody titers and 33% (10/30) of the samples had positive blood smears. Regarding B. bigemina, > 86% of the samples in both groups tested positive for B. bigemina DNA and antibodies; there was no difference in the antibody titers between the groups. There were no clinical cases of cattle tick fever in calves aged 11 to 22 months.

Conclusions: In comparison with the control treatment, the strategic control regimen against R. microplus with FLU that was implemented in the present study did not negatively affect the enzootic stability status of A. marginale and B. bigemina in the herd up to 22 months of age. The enzootic stability status of B. bovis was not reached by either group. These results likely represent a characteristic of the local tick population, so further studies should be performed.

Keywords: Rhipicephalus microplus; Anaplasmosis; Babesiosis; Isoxazoline.

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Conflict of interest statement

DCR, TS and ST are employees of MSD/Merck Animal Health. The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Experimental design of Experiment 2 to evaluate the enzootic stability of cattle tick fever in the herd after treatment with FLU in animals naturally infested with Rhipicephalus microplus. D, Study day; FIFLUA, fipronil + fluazuron group; FLU, fluralaner group; iELISA, indirect enzyme-linked immunosorbent assay; PCV, packed cell volume
Fig. 2
Fig. 2
Ticks between the legs of cattle in the group treated with fluralaner. A Animal 5411 on study day 63 when treated. B animal 5359 on study day 133 when treated again
Fig. 3
Fig. 3
iELISA antibody titers against tick fever agents in cattle treated with fluralaner and a control treatment against the tick Rhipicephalus microplus. a Anaplasma marginale, b Babesia bigemina, c Babesia bovis. No significant difference between the FLU and FIFLUA groups was observed (P ≥ 0.05). FIFLUA, Fipronil + fluazuron group; FLU, fluralaner group; iELISA, indirect enzyme-linked immunosorbent assay
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References

    1. Machado RZ, da Silva JB, André MR, Gonçalves LR, Matos CA, Obregón D. Outbreak of anaplasmosis associated with the presence of different Anaplasma marginale strains in dairy cattle in the states of São Paulo and Goiás. Rev Bras Parasitol Vet. 2015;24:438–446. doi: 10.1590/S1984-29612015078. - DOI - PubMed
    1. Heller LM, Zapa DMB, Couto LFM, de Aquino Gontijo LM, Nicaretta JE, de Morais IML, et al. Techniques for monitoring dairy calves against the tick fever agents: a comparative analysis. Vet Res Commun. 2022;46:879–902. doi: 10.1007/s11259-022-09915-6. - DOI - PubMed
    1. Nicaretta JE, de Melo Junior RD, Naves RB, de Morais IML, Salvador VF, Leal LLLL, et al. Selective versus strategic control against Rhipicephalus microplus in cattle: a comparative analysis of efficacy, animal health, productivity, cost, and resistance management. Vet Parasitol. 2023;321:109999. doi: 10.1016/j.vetpar.2023.109999. - DOI - PubMed
    1. Nicaretta JE, Zapa DMB, Couto LFM, Heller LM, Cavalcante AS de A, Cruvinel LB, et al. Rhipicephalus microplus seasonal dynamic in a Cerrado biome, Brazil: An update data considering the global warming. Vet Parasitol. 2021;296:109506. - PubMed
    1. Gomes LVC, Lopes WDZ, Teixeira WFP, Maciel WG, Cruz BC, Felippelli G, et al. Population dynamics and evaluation of the partial selective treatment of crossbreed steers naturally infested with Rhipicephalus (Boophilus) microplus in a herd from the state of Minas Gerais in Brazil. Vet Parasitol. 2016;220:72–76. doi: 10.1016/j.vetpar.2016.02.029. - DOI - PubMed

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