scholarly journals COMPARACIÓN ENTRE EL MODELO PROBIT Y EL MODELO DE HILL PARA DETERMINAR LA EFICACIA DE IVERMECTINA SOBRE LARVAS DE Rhipicephalus (Boophilus) microplus (ACARI, IXODIDA: IXODIDAE) MEDIANTE LA TÉCNICA DE INMERSIÓN.

2021 ◽  
Vol 19 (suplemento) ◽  
Author(s):  
J Torrents
Keyword(s):  
Experimental Data ◽  
Probit Model ◽  
Immersion Test ◽  
Boophilus Microplus ◽  
Hill Model ◽  
Precise Analysis ◽  
Resistant Strains ◽  
Para Determinar ◽  
The Hill

The aim of this study was to propose an alternative statistic treatment for the results obtained by testing the in vitro efficacy of ivermectin (IVM) against R. microplus using the larval immersion test in order to detect the emergence of resistant strains. The statistical analysis of the results obtained by this technique is standardized by the FAO who proposes the use of the Probit model. However there are alternative mathematical models that allow a more precise analysis of experimental data generating more information as nonlinear logistic equation, also called the Hill model. The results of the IVM efficacy against a sensible strain of R. microplus were analysed whit both model. A comparison between the results obtained with PROBIT and Hill model showed that the last one was able to make a more precise fit of the experimental data, generating more information about small IVM concentrations.  The C50 (13.58 ppm) obtained with Probit model result smaller than the obtained with the Hill model (14.24 ppm), however the C90, C99 and the discriminant dose (19.31 ppm, 25.74 ppm, 51.48 ppm) obtained with de Hill model were bigger than the obtained with the Probit model (17.50 ppm, 21.98 ppm, 43.96 ppm).

scholarly journals SENSIBILIDAD DE LA GARRAPATA COMÚN DEL BOVINO Rhipicephalus (Boophilus) microplus A IVERMECTINA ESTIMADA CON EL MODELO SIGMOIDEO DE RESPUESTA MÁXIMA O DE HILL

2021 ◽  
Vol 19 (suplemento) ◽  
Author(s):  
J Torrents
Keyword(s):  
Statistical Analysis ◽  
Boophilus Microplus ◽  
Susceptible Strain ◽  
Maximum Response ◽  
Hill Coefficient ◽  
Concentration Effect ◽  
Hill Model ◽  
Low Concentration ◽  
Immersion Technique ◽  
The Hill

The aim of this study was to obtain pharmacodynamics parameters to detect resistance or susceptibility of R. microplus strains to ivermectin (IVM). Two larvae samples; a susceptible strain (S) and field isolation (T) were treated with increasing concentrations of IVM using the larvae immersion technique the efficacy values measured at 24 hours were analysed with the sigmoidal maximum response so called Hill model as statistical analysis. The results obtained showed that the IVM have an all or nothing response represented by the Hill coefficient value >1 in both samples. Additionally, a low concentration effect was observed as E0 de 12.83% (S) and 9.91% (T). The field isolation larvae were susceptible to IVM in comparison with the susceptible strain by the resistance ratio (RR) which in one case was not significantly greater that one (RR50= 0.756 and RR90=1.009).

scholarly journals Evaluación de Tres Formulaciones Comerciales de Aplicación Pour on Bajo Condiciones de Campo y su Efecto in vitro en el Control de Boophilus microplus (Acari: Ixodidae), en Bovinos de Ceja de Selva

2016 ◽  
Vol 27 (1) ◽  
pp. 145 ◽  
Author(s):  
Del Castillo L. Del Castillo L. ◽  
Rosa Pinedo V. ◽  
Luis Rodríguez I. ◽  
Amanda Chávez V.
Keyword(s):  
Boophilus Microplus ◽  
Para Determinar

El objetivo del presente estudio fue evaluar la eficacia de tres formulaciones comerciales pour on bajo condiciones de campo e in vitro sobre el control de Rhipicephalus (Boophilus) microplus en bovinos naturalmente infestados, en la zona de Oxapampa, Perú. Se trabajó con 105 bovinos infestados con 30 o más teleoginas en un flanco. Los animales se distribuyeron en tres grupos de 35 animales c/u tratados con Fipronil 1% + Abamectina 0.5% + Aceite de Neem 2% (FAN), Flumetrina 1% + Eprinomectina 0.5% (FE) y Flumetrina 1% + Fluazurón 2.5% (FF), respectivamente. La dosis empleada fue de 1 ml/10 kg p.v en la línea dorsal (pour on). Se contó el número de teleoginas (≥4.5 mm) sobre los animales los días 0, 7, 14, 21, 28 y 56 postratamiento. Se calculó la eficacia mediante la prueba de reducción de recuento de teleoginas. Para el estudio in vitro se colectaron 50 teleoginas de cada grupo a las 24, 48 y 72 h postratamiento, así como de un grupo no dosificado. Se inmovilizaron con cinta adhesiva 30 teleoginas de pesos similares (160-340 mg) por grupo y se incubaron a 27 ºC y 85% de humedad relativa por 21 días. Se evaluó mortalidad y oviposición. Los huevos se incubaron por 30 días para determinar la eclosión larval, eficiencia reproductiva y eficacia in vitro. El estudio en campo demostró que las combinaciones FAN (99.4-100%), FE (95.8-98.4%) y FF (97.3-98.8%) fueron eficaces (>95%) los días 7-28, 7-14 y 21-56, respectivamente. In vitro, las combinaciones FAN y FF tuvieron 100% de eficacia en las tres colectas; mientras que la combinación FE mostró una eficacia del 98-99% en teleoginas colectadas a las 48 y 72 h postratamiento.

scholarly journals Mechanisms of Resistance to Bromophos-ethyl in Two Strains of the Cattle Tick Boophilus microplus

1978 ◽  
Vol 31 (4) ◽  
pp. 317 ◽  
Author(s):  
CA Schuntner ◽  
PG Thompson
Keyword(s):  
Resistance Mechanism ◽  
Product Inhibition ◽  
Boophilus Microplus ◽  
Water Soluble ◽  
Cattle Tick ◽  
Major Pathway ◽  
Degradation Rates ◽  
Resistant Strains

B. micro plus larvae of the organophosphorus-resistant Biarra and Mt Alford strains were respectively 8 x and 35 x resistant to bromophos-ethyl compared with larvae of the standard organophosphorussusceptible Yeerongpilly strain. Both resistant strains had acetylcholinesterase with decreased sensitivity to inhibition by the oxon of bromophos-ethyl in vitro; this was the only resistance mechanism apparent in the Biarra strain but Mt Alford larvae were protected additionally by increased metabolism of the oxon in vivo to water-soluble products. Total degradation rates for the parent chemical were similar in all strains and relatively slow. Both bromophos-ethyl and its oxon were potent inhibitors of mixed-function oxidase in vivo and it seemed that the slow oxidative metabolism of bromophos-ethyl (the major pathway) could be attributed to substrate and/or product inhibition. No phenolic metabolites were detected and the major water-soluble metabolite was identified electrophoretically as 2,5-dichlorophenyl-o-ethyl phosphate. Some debrominated oxon was detected in all samples of larvae after dosage with bromophos-ethyl or with its oxon, indicating that oxidation of bromophos-ethyl to the oxon, debromination of the oxon followed by deethylation was a major degradative sequence.

scholarly journals Efficacy of commercial synthetic pyrethroids and organophosphates associations used to control Rhipicephalus (Boophilus) microplus in Southern Brazil

2017 ◽  
Vol 26 (4) ◽  
pp. 500-504 ◽  
Author(s):  
Caroline Zamperete Reginato ◽  
Gustavo Cauduro Cadore ◽  
Fernanda Rezer de Menezes ◽  
Luis Antonio Sangioni ◽  
Fernanda Silveira Flores Vogel
Keyword(s):  
Rio Grande ◽  
Immersion Test ◽  
The State ◽  
Boophilus Microplus ◽  
Active Principle ◽  
Synthetic Pyrethroids ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Cattle Farms

Abstract This study evaluated the acaricidal efficiency of synthetic pyrethroids (SP) associated with organophosphates (OP) against Rhipicephalus (Boophilus) microplus populations in the state of Rio Grande do Sul, Southern Brazil. Ticks were collected in 54 cattle farms and tested using in vitro adult immersion test against four commercially available acaricide mixtures of SP and OP. Only one of four acaricides, comprising a mixture of cypermethrin, chlorpyrifos, and fenthion, had a mean efficiency higher than 95%, and was effective in 94.44% (51/54) of the cattle farms tested. The acaricide with a mixture of cypermethrin, chlorpyrifos, and citronelall had the lowest mean efficiency (62.11%), and was effective in 29.62% (16/54) of cattle farms tested. Furthermore, R. (B.) microplus in Southern Brazil exhibited differing degrees of resistance to SP and OP mixtures. The results suggest that the presence of fenthion contributes to the higher efficiency of the formulation with this active principle. This is possibly due to its recent commercial availability, as tick populations have been lower challenged with this product. Monitoring the resistance of ticks to carrapaticides is essential to maximize the efficiency of these products in the control of R. (B.) microplus.

scholarly journals In Vitro Detection of Acaricidal Resistance Status of Rhipicephalus (Boophilus) microplus against Commercial Preparation of Deltamethrin in Coastal Areas of South Gujarat, India

2020 ◽  
Vol 16 (01) ◽  
pp. 32-36
Author(s):  
Dharmesh C Patel ◽  
Jayesh B Solanki ◽  
Niranjan Kumar
Keyword(s):  
Chemical Method ◽  
Immersion Test ◽  
Coastal Areas ◽  
Boophilus Microplus ◽  
Lethal Concentration ◽  
Median Lethal Concentration ◽  
Resistance Level ◽  
Commercial Preparation

A total of 2617 bovines (1682 cattle and 935 buffaloes) of coastal districts (Bharuch, Surat, Navsari and Valsad) of South Gujarat were screened for tick Rhipicephalus (Boophilus) microplus, the most economically important ectoparasite of bovines worldwide. Farmers chiefly relied on chemical acaricides (67.52%) to kill the ticks, and under chemical method 44.09, 24.17, 30.50 and 1.24 % animals had received cypermethrin, deltamethrin, ivermectin and fipronil, respectively, thus favouring the resistance. In adult immersion test (AIT), the median lethal concentration (LC50) was 144.23, 93.97, 141.67 and 57.89 ppm for deltamethrin in Bharuch, Surat, Navsari and Valsad district, respectively. Resistance level was I in Valsad and II in other 3 districts for deltamethrin in AIT. In larval packet test (LPT), the median LC50 was 297.29, 126.81, 127.83 and 93.92 ppm for deltamethrin in Bharuch, Surat, Navsari and Valsad district, respectively. Resistance level was III in Bharuch and II in other district in LPT.

scholarly journals DETERMINACIÓN DE LA CONCENTRACIÓN EFECTIVA 50, 90 Y 99 DE IVERMECTINA SOBRE UNA CEPA DE GARRAPATA COMÚN DEL BOVINO (Rhipicephalus (Boophilus) microplus) PROVENIENTE DE LA PROVINCIA DE SANTA FE-ARGENTINA

2021 ◽  
Vol 19 (suplemento) ◽  
Author(s):  
J Torrents
Keyword(s):  
Reference Strain ◽  
Statistical Treatment ◽  
Probit Model ◽  
Boophilus Microplus ◽  
Resistance Ratio ◽  
Santa Fe ◽  
Resistant Strains ◽  
Sensitivity Data ◽  
Native Strains ◽  
Different Doses

The aim of this study was to obtain the sensitivity data of the native strains of R. microplus to ivermectin (IVM) in the province of Santa Fe-Argentina, in order to detect the emergence of resistant strains. Native (field isolation) and susceptible (reference) larvae of R. microplus were treated with increasing concentrations of IVM in order to determine its efficacy at different doses. The statistical treatment of the concentration-efficacy curves was performed by the PROBIT model, who is a standardized method proposed by FAO. The results obtained indicated that the larvae isolated were susceptible, being the values of LD50 (9.66 ppm) and LD90 (17.41 ppm), which were lower than those of the reference strain (LD50:13.58 ppm, LD90:19.31 ppm), and the RR (resistance ratio) were less than one (RR50: 0.711; RR90: 0.901). The DL99 (51.48 ppm) was only obtained in the reference strain to determine the discriminant dose (DL99x2), which is a parameter that could be used to easily discriminate susceptible and resistant larvae populations.

scholarly journals Efficacy of extracts from plants of the Brazilian Pantanal against Rhipicephalus (Boophilus)microplus

2013 ◽  
Vol 22 (4) ◽  
pp. 532-538 ◽  
Author(s):  
Larissa Bezerra dos Santos ◽  
Juliana Kátia Souza ◽  
Barbara Papassoni ◽  
Dyego Gonçalves Lino Borges ◽  
Geraldo Alves Damasceno Junior ◽  
...  
Keyword(s):  
Immersion Test ◽  
Acaricidal Activity ◽  
Boophilus Microplus ◽  
Stage I ◽  
Fruit Extract ◽  
Mato Grosso ◽  
Sesbania Virgata ◽  
Brazilian Pantanal ◽  
Mato Grosso Do Sul

This research evaluated the in vitro acaricidal activity of extracts from 21 plant species from the Pantanal of Mato Grosso do Sul. During stage I, a larval immersion test was performed using three extract concentrations (5%, 20%, and 40%). During stage II, we used only plants that showed over 95% efficiency at the 40% concentration in stage I in an amount sufficient for the adult immersion test. Aeschynomene denticulata, Angelonia hirta, Aspilia latissima, Caperonia castaneifolia, Centratherum punctatum, Crotalaria micans, Diodia kuntzei, Echinodorus paniculatus, Hyptis mutabilis, Lantana canescens, Melanthera latifolia, Ocotea diospyrifolia, Richardia grandiflora, Sebastiana hispida, Tocoyena formosa, Zanthoxylum rigidum, and Sesbania virgata (fruit extract) showed acaricidal activity against the larval stage ofRhipicephalus (Boophilus)microplus higher than 95% at a 40% (w/v) concentration, while Hippocratea volubilis and Randia armatashowed moderate efficacy and Croton glandulosus andSenna obtusifolia had no effect. The M. latifolia, A. hirta, R. grandiflora, and A. latissima raw extracts were evaluated for their activity against adults, and only A. hirta showed an efficacy close to 90%. Eighteen extracts had an efficacy of up to 95% against larvae at a 40% concentration, seven extracts were effective at 20%, and only one (Sebastiana hispida) was effective at a 5% concentration.

scholarly journals Evaluation of phytotherapy alternatives for controlling Rhipicephalus (Boophilus) microplus in vitro

2017 ◽  
Vol 26 (3) ◽  
pp. 299-306 ◽  
Author(s):  
José Pablo Villarreal Villarreal ◽  
Pedro Rassier dos Santos ◽  
Maria Antonieta Machado Pereira da Silva ◽  
Rosaria Helena Machado Azambuja ◽  
Carolina Lambrecht Gonçalves ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Sunflower Seed ◽  
Immersion Test ◽  
Tick Control ◽  
Acaricidal Activity ◽  
Boophilus Microplus ◽  
Chemical Components ◽  
Brazil Nut ◽  
Acaricidal Efficacy

Abstract The objective of this study was to identify the main chemical components of the essential oil of Cuminum cyminum L. (cumin) and of the fixed oils of Bertholletia excelsa (Brazil nut) and of Helianthus annuus (sunflower seed). As well as testing the three oils and three different commercial synthetic acaricides against engorged females of Rhipicephalus (Boophilus) microplus in order to explore their acaricidal efficacy. Six different concentrations of the oils (200, 100, 50, 25, 12.5 and 6.25 mg/mL) and the active principles were evaluated with the Adult Immersion Test (AIT). The two main chemicals components of C. cyminum L. were the cuminaldehyde and the γ-terpinene. In both B. excelsa and H. annuus were the linoleic and oleic acid. C. cyminum L. showed high acaricidal activity (100%) over the engorged females and on their reproductive characteristat from the concentration of 100 mg/mL. B. excelsa and H. annuus had low acaricidal activity (39.39% and 58.75% in the concentration of 200 mg/mL respectively). The amidine and the pyrethroid (35.12% and 1.50% respectively). It can be concluded that the oil of C. cyminum L. may be a phytoterapic alternative for the cattle's tick control.

scholarly journals Acaricide resistance of Rhipicephalus (Boophilus) microplus in State of Mato Grosso do Sul, Brazil

2011 ◽  
Vol 20 (2) ◽  
pp. 127-133 ◽  
Author(s):  
Renato Andreotti ◽  
Felix David Guerrero ◽  
Mariana Aparecida Soares ◽  
Jacqueline Cavalcante Barros ◽  
Robert John Miller ◽  
...  
Keyword(s):  
Gene Mutation ◽  
Pyrethroid Resistance ◽  
Immersion Test ◽  
The State ◽  
Boophilus Microplus ◽  
Acaricide Resistance ◽  
Mato Grosso ◽  
Pcr Assays ◽  
Mato Grosso Do Sul

This study was conducted to obtain an epidemiological view of acaricide resistance in populations of Rhipicephalus (Boophilus) microplus in the State of Mato Grosso do Sul. Twenty-four tick samples were collected from municipalities in the State where farmers had reported concerns about resistance to or failure of tick control. These ticks were subjected to in vitro resistance detection assays using the adult immersion test (AIT). The efficacy of alpha-cypermethrin, cypermethrin and amitraz treatments on samples collected throughout the State was generally poor. AIT showed efficacy > 90% from the use of DDVP + chlorfenvinphos) (20 out of 21 municipalities), dichlorvos + cypermethrin (10 out of 16 municipalities) and cypermethrin + citronella + chlorpyrifos + piperonyl butoxide (20 out of 21 municipalities). PCR assays were used to detect the presence of pyrethroid resistance-associated sodium channel gene mutation. Larvae from three different populations that had previously been diagnosed as pyrethroid-resistant, through AIT, were evaluated. The PCR assays showed that the pyrethroid resistance-associated gene mutation was absent from these three populations. This study confirms that the emergence of resistance is a constant challenge for the livestock industry, and that development of resistance continues to be a major driver for new antiparasitic drugs to be developed.

scholarly journals Acaricide activity of leaves extracts of Sambucus australis Schltdl. (Caprifoliaceae) at 2% on engorged females of Rhipicephalus (Boophilus) microplus

2011 ◽  
Vol 41 (12) ◽  
pp. 2159-2163 ◽  
Author(s):  
Felipe da Silva Krawczak ◽  
Andréia Buzatti ◽  
Felipe Lamberti Pivoto ◽  
Luís Antônio Sangioni ◽  
Fernanda Silveira Flores Vogel ◽  
...  
Keyword(s):  
Folk Medicine ◽  
Ethanol Extract ◽  
Immersion Test ◽  
Tick Control ◽  
Boophilus Microplus ◽  
Economic Losses ◽  
Cattle Tick ◽  
Active Metabolites ◽  
Parasite Infections

Parasite infections caused by Rhipicephalus (Boophilus) microplus are responsible for the most of economic losses in producing-cattle countries in tropical and subtropical areas. Indiscriminate uses of chemical acaricides have contributed with the appearance of tick resistance to many drugs available in the marketplace, and it is a serious problem in the tick control. Flowers of Sambucus australis (South America), called "sabugueiro-from-Brazil", are used on infusions or decoctions forms in the folk medicine with diuretic, antipyretic, anti-inflammatory, and laxative purpose, also employed for treating respiratory diseases in human. The main goal of this study was to evaluate in vitro potential of S. australis leaves extracts as an acaricide agent. Ethanol extract at 70% has been dehydrated and a fraction was suspended in 70% ethanol or in distillated water at final concentration of 2% (0.2mg-1). Using the immersion test of engorged females the efficiency results were obtained in 34% and 66% with the leaves extract diluted in water and 70% ethanol, respectively. This study is the first report on acaricidal activity of S. australis against cattle tick. Further studies to determine the active metabolites in different stages of S. australis could aid to identify suitable extracts to be tested in the R. (B.) microplus control.

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