Mode of Inheritance of Amitraz Resistance in a Brazilian Strain of the Southern Cattle Tick, Boophilus microplus (Acari: Ixodidae)*

Li, Andrew Y.; Davey, Ronald B.; Miller, Robert J.; George, John E.

doi:10.1007/s10493-005-3260-9

Cited by 43 publications

(32 citation statements)

References 30 publications

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“…Initially it was hypothesized that the spread of this tick would be limited and localized around the farms where the Girolando cattle were first introduced allowing eradication. However, the current situation and the notorious acaricide resistance of this tick of Brazilian origin (Baffi et al, 2008, Li et al, 2005, Martins and Furlong, 2001, Mendes et al, 2011, eradication would be a time consuming and expensive exercise similar to the eradication campaigns at the border between Mexico and Texas (USA) (Temeyer et al, 2004).…”

Section: Project (Milk and Meat Sectors Support Project) This Projecmentioning

confidence: 99%

New foci of Rhipicephalus microplus in West Africa

Madder

Adehan²,

Deken

et al. 2012

Exp Appl Acarol

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The invasive character of Rhipicephalus microplus was observed in Benin, the second West-African country from which this tick species has been collected after the initial confirmed record in Ivory Coast in 2007. A cross-sectional study was carried out in the Department of Mono to examine the presence of the tick Rhipicephalus microplus. The survey covered 9 herds (villages) in an agro-ecological zone inhabited by agro-pastoralists, including the State Farm of Kpinnou that imported Girolando cattle from Brazil. Almost 800 ticks were sampled from 36 cattle, on average four cattle per village.The morphological identification revealed ticks of two different genera: Rhipicephalus spp. and Amblyomma spp. Within the genus Rhipicephalus, R. microplus was the only representative of the species previously known as Boophilus or blue ticks. Its taxonomic identity was confirmed molecularly by PCR-RFLP.A comparison was made with the situation of R. microplus in Brazil.

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Section: Project (Milk and Meat Sectors Support Project) This Projecmentioning

confidence: 99%

New foci of Rhipicephalus microplus in West Africa

Madder

Adehan²,

Deken

et al. 2012

Exp Appl Acarol

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“…The unfed adult D. albipictus ticks were obtained by infesting larvae under a muslin sleeve on the back of a stanchioned Hereford heifer calf at the KBUSLIRL. Larvae were allowed to develop to the metanymphal stage, after which they were forcibly removed from the host (Li et al 2005) and maintained under the same conditions as for A. americanum until they molted to the adult stage. All unfed D. albipictus adult ticks used in this study were dissected within 24 h after molting.…”

Section: Experimental Animalsmentioning

confidence: 99%

Serotonin-like immunoreactivity in the central nervous system of two ixodid tick species

Hummel

Witt

2007

Exp Appl Acarol

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Immunocytochemistry was used to describe the distribution of serotonin-like immunoreactive (5HT-IR) neurons and neuronal processes in the central nervous system (CNS), the synganglion, of two ixodid tick species; the winter tick, Dermacentor albipictus and the lone star tick, Amblyomma americanum. 5HT-IR neurons were identified in the synganglion of both tick species. D. albipictus had a significantly higher number of 5HT-IR neurons than A. americanum. The labeling pattern and number of 5HT-IR neurons were significantly different between sexes in D. albipictus, but were not significantly different between sexes in A. americanum. 5HT-IR neurons that were located in the cortex of the synganglion projected processes into the neuropils, invading neuromeres in the supraesophageal ganglion including the protocerebrum, postero-dorsal, antero-dorsal and cheliceral neuromeres. In the subesophageal ganglion, dense 5HT-IR neuronal processes were found in the olfactory lobes, pedal, and opisthosomal neuromeres. Double-labeling with neurobiotin backfilled from the first leg damaged at the Haller's organ revealed serotoninergic neuronal processes surrounding the glomeruli in the olfactory lobes. The high number of the 5HT-IR neurons and the extensive neuronal processes present in various regions of the synganglion suggest that serotonin plays a significant role in tick physiology.

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“…Early detection of resistance is an important preventive tool for moderating the selection pressure exerted by acaricide treatments on the genes present in field populations (LI et al, 2005). Resistance in R.…”

Section: Introductionmentioning

confidence: 99%

Comparison of three larval bioassays to evaluate susceptibility of Rhipicephalus (Boophilus) microplus to amitraz

Santos

Klafke²,

Pappen

et al. 2013

Rev. Bras. Parasitol. Vet.

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Field samples of Rhipicephalus (Boophilus) microplus from the state of Rio Grande do Sul, Brazil, were assessed using the following methods: larval packet test (LPT), larval immersion test (LIT) and syringe immersion test (SIT). The following parameters were determined for each population and for the Mozo susceptible reference strain: lethal concentration for 50% (LC 50 ) with its 95% confidence interval (95% CI), regression line slope and resistance ratio (RR). Using the LPT, only one population was susceptible to amitraz, presenting a RR of 1.9. Using the same technique, the other populations presented RRs of between 92.9 and 3445.8 and were considered resistant. The LC 50 of the Mozo strain calculated using the LPT, LIT and SIT was 2.9, 27.3, and 52.7 µg/mL, respectively. In general, a good fit to the probit statistical model was only achieved using the LPT. The results obtained in this study impair recommendations for using the LIT and SIT to diagnose amitraz resistance in R. (B.) microplus populations. Additional studies are required to improve the sensitivity of these tests in relation to the LPT.Keywords: Rhipicephalus (Boophilus) microplus, amitraz, bioassays, resistance diagnosis. ResumoAmostras de Rhipicephalus (Boophilus) microplus coletadas à campo no Rio Grande do Sul, Brasil, foram analisadas pelos seguintes métodos: teste do pacote de larvas (TPL), teste de imersão de larvas (TIL) e teste de imersão em seringas (TIS). Os seguintes parâmetros foram determinados para cada população e para a amostra referência suscetível Mozo: concentração letal para 50% (CL 50 ) e seu intervalo de confiança de 95% (IC95%), inclinação da reta de regressão e os fatores de resistência (FR). Pelo TPL, apenas uma população foi sensível ao amitraz, com FR de 1,9. Utilizando a mesma técnica, as outras amostras apresentaram FR entre 92,9 e 3445,8 sendo consideradas resistentes. As CL 50 da cepa Mozo calculadas por meio do TPL, TIL e TIS foram 2,9, 27,3 e 52,7 µg/mL, respectivamente. De forma geral, a adequação ao modelo estatístico de probitos só foi alcançada com o uso do TPL. Os resultados obtidos no presente estudo limitam a recomendação de uso do TIL e TIS para diagnóstico de resistência ao amitraz em populações de R. (B.) microplus. Estudos adicionais são necessários para aprimorar a sensibilidade destes testes em relação ao LPT.Palavras-chave: Rhipicephalus (Boophilus) microplus, amitraz, bioensaio, diagnóstico de resistência.

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Mode of Inheritance of Amitraz Resistance in a Brazilian Strain of the Southern Cattle Tick, Boophilus microplus (Acari: Ixodidae)*

Cited by 43 publications

References 30 publications

New foci of Rhipicephalus microplus in West Africa

New foci of Rhipicephalus microplus in West Africa

Serotonin-like immunoreactivity in the central nervous system of two ixodid tick species

Comparison of three larval bioassays to evaluate susceptibility of Rhipicephalus (Boophilus) microplus to amitraz

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