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Heylen DJA, Labuschagne M, Meiring C, van der Mescht L, Klafke G, Costa Junior LM, Strydom T, Wentzel J, Shacklock C, Halos L, Maree F, Fourie J, Madder M, Evans A. Phenotypic and genotypic characterization of acaricide resistance in Rhipicephalus microplus field isolates from South Africa and Brazil. Int J Parasitol Drugs Drug Resist 2024; 24:100519. [PMID: 38168594 PMCID: PMC10797136 DOI: 10.1016/j.ijpddr.2023.100519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 12/20/2023] [Accepted: 12/20/2023] [Indexed: 01/05/2024]
Abstract
Rhipicephalus (Boophilus) microplus is one of the most successful ticks infesting cattle around the world. This highly-invasive species transmits cattle parasites that cause cattle fever leading to a high socio-economic burden. Tick eradication programs have often failed, due to the development of acaricide resistance. Here we characterize acaricide resistance in a large number of tick isolates from regions in South Africa (KwaZulu Natal, Mpumalanga, Western & Eastern Cape provinces) and two Brazilian regions. By means of Larval Packet Tests (LPT's) acaricide resistance was evaluated against five commonly used acaricides (chlorfenvinphos, fipronil, deltamethrin, amitraz, and ivermectin). Furthermore, the coding region containing the knock down resistance (kdr) mutation, known to result in pyrethroid resistance, was sequenced. Resistance to at least one acaricide class was reported in each of the five regions, and a high proportion of tick isolates exhibited multi-resistance to at least two acaricide classes (range: 22.2-80.0%). Furthermore, resistance ratios (RR) showed high spatial variation (intercontinental, as well as regional) but low regional spatial autocorrelation. Previous and current acaricide use correlated with current RR, and several combinations of acaricide RR were positively correlated. Moreover, fipronil resistance tended to be higher in farms with more intense acaricide use. The kdr-mutations provided the ticks a fitness advantage under the selection pressure of synthetic pyrethroids based on population (kdr-allele frequency) and individual level data (genotypes). The data show the threat of acaricide (multi-)resistance is high in Brazil and South Africa, but acaricide specific levels need to be assessed locally. For this purpose, gathering complementary molecular information on mutations that underlie resistance can reduce costs and expedite necessary actions. In an era of human-caused habitat alterations, implementing molecular data-driven programs becomes essential in overcoming tick-induced socio-economic losses.
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Affiliation(s)
- Dieter J A Heylen
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Wilrijk, Belgium; Interuniversity Institute for Biostatistics and statistical Bioinformatics, Hasselt University, Diepenbeek, Belgium.
| | - Michel Labuschagne
- Clinomics, P.O. Box 11186, Universitas, Bloemfontein, 9321, Uitzich Road, Bainsvlei, Bloemfontein, 9338, South Africa; Clinglobal, B03/04, The Tamarin Commercial Hub, Jacaranda Avenue, Tamarin, 90903, Mauritius.
| | - Christina Meiring
- Clinomics, P.O. Box 11186, Universitas, Bloemfontein, 9321, Uitzich Road, Bainsvlei, Bloemfontein, 9338, South Africa; Clinglobal, B03/04, The Tamarin Commercial Hub, Jacaranda Avenue, Tamarin, 90903, Mauritius.
| | - Luther van der Mescht
- Clinvet International Pty (Ltd), Uitzich Road, Bainsvlei, Bloemfontein, 9338, South Africa; Department of Zoology and Entomology, University of the Free State, Bloemfontein, South Africa.
| | - Guilherme Klafke
- Instituto de Pesquisas Veterinárias Desidério Finamor, Centro de Pesquisa em Saúde Animal, Estrada do Conde 6000, Eldorado do Sul, RS, 92990-000, Brazil.
| | | | - Tom Strydom
- MSD ANIMAL HEALTH, Private Bag X2026, Isando, 1600, South Africa.
| | - Jeanette Wentzel
- Hans Hoheisen Wildlife Research Station, Department of Veterinary Tropical Diseases, University of Pretoria, South Africa.
| | | | - Lénaig Halos
- Bill & Melinda Gates Foundation, Seattle, WA, USA.
| | - Francois Maree
- Clinomics, P.O. Box 11186, Universitas, Bloemfontein, 9321, Uitzich Road, Bainsvlei, Bloemfontein, 9338, South Africa.
| | - Josephus Fourie
- Clinvet International Pty (Ltd), 1479 Talmadge Hill South, Waverly, NY, 14892, USA.
| | - Maxime Madder
- Clinglobal, B03/04, The Tamarin Commercial Hub, Jacaranda Avenue, Tamarin, 90903, Mauritius.
| | - Alec Evans
- Clinglobal, B03/04, The Tamarin Commercial Hub, Jacaranda Avenue, Tamarin, 90903, Mauritius.
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