Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2016-09-08T13:37:00Z No. of bitstreams: 1 2011 - Mariana Guedes Camargo.pdf: 1490617 bytes, checksum: fa92cbaf85207d3979daee781f5d74b1 (MD5) / Made available in DSpace on 2016-09-08T13:37:00Z (GMT). No. of bitstreams: 1 2011 - Mariana Guedes Camargo.pdf: 1490617 bytes, checksum: fa92cbaf85207d3979daee781f5d74b1 (MD5) Previous issue date: 2011-08-18 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The formulations of entomopathogenic fungi to control ticks has been widely studied. The present study evaluated the efficacy of Metarhizium anisopliae sensu lato (s.l.) and Beauveria bassiana oily formulations on different Rhipicephalus microplus stages. The efficacy of conidial aqueous suspensions was compared to the efficacy of conidia formulated in 10, 15 or 20% mineral oil. Twelve groups were studied: one control aqueous, three control groups oil-based at 10%, 15% or 20%, two fungal aqueous suspensions of M. anisopliae s.l. or B. bassiana and M. anisopliae s.l. or B. bassiana oil-based formulations at 10%, 15% or 20%. To prepare aqueous suspensions and oily formulations, fungal isolates were cultivated on grains rice in polypropylene bags. The conidial suspensions and formulations had concentration of 108 conidia/mL. Bioassays were repeated twice. After treatment, the biological parameters of engorged females were evaluated; the following parameters were evaluated in the bioassays with eggs: period of incubation, period of hatch and hatching percentage; in bioassays with larva mortality was evaluated. Metarhizium anisopliae s.l. and B. bassiana oil-based formulations were more effective than aqueous suspensions to R. microplus eggs, larvae and engorged females. Metarhizium anisopliae s.l. oil-based formulations caused significant effects in all biological parameters of engorged females while B. bassiana oil-based formulations modified significantly the nutritional index only. Metarhizium anisopliae s.l. and B. bassiana formulated in mineral oil caused a control percentage up to 93.69% and 21.67%, respectively, while M. anisopliae s.l. and B. bassiana aqueous suspension caused a control percentage of 18.70% and 1.72%, respectively. Eggs treated with M. anisopliae s.l. and B. bassiana oil-based formulations had reduced percentage of hatch up to 102.5 and 3.65 times, respectively. In the bioassay with larvae, M. anisopliae s.l. oil-based formulations caused approximately 100% mortality five days after treatment, while larva treated with B. bassiana oil-based formulations reached 100% mortality only at day 20 after treatment. Larva from oil-based control groups had mortality at day 15 after treatment, indicating possible toxic effect off the oil for this R. microplus stage. The results showed that M. anisopliae s.l., Ma 959 isolate, was more virulent to R. microplus engorged females, eggs and larvae than B. bassiana, Bb 986 isolate. The fungal mineral oily formulations tested were more effective than the aqueous suspension. Oil-based formulations at 10%, 15% or 20% enhances the activity of M. anisopliae s.l., Ma 959, and B. bassiana, Bb 986, to R. microplus tick and can be used as an adjuvant for oily formulations / A utiliza??o de formula??es de fungos entomopatog?nicos no controle de carrapatos tem sido amplamente estudada. O presente estudo avaliou a efic?cia de formula??es do isolado Ma 959 de Metarhizium anisopliae sensu lato (s.l.) e Bb 986 de Beauveria bassiana contendo 10%, 15% e 20% de ?leo mineral sobre ovos, larvas e f?meas ingurgitadas de Rhipicephalus microplus, al?m de comparar a efici?ncia entre formula??es oleosas e suspens?es aquosas dos mesmos isolados f?ngicos sobre as fases do desenvolvimento do carrapato R. microplus. Foram formados doze grupos: controle aquoso e controles com 10%, 15% ou 20% de ?leo mineral, suspens?o aquosa de M. anisopliae s.l. ou B. bassiana e formula??es de M. anisopliae s.l. ou B. bassiana contendo 10%, 15% ou 20% de ?leo mineral. Para o preparo das suspens?es aquosas e formula??es oleosas, os isolados f?ngicos foram cultivados em gr?os de arroz acondicionado em sacos de polipropileno. As suspens?es e formula??es conidiais utilizadas possu?am concentra??o de 108 con?dios/mL. Os bioensaios foram repetidos duas vezes. Os par?metros biol?gicos das f?meas ingurgitadas foram avaliados; em rela??o aos ovos foram avaliados os per?odos de incuba??o e eclos?o e o percentual de eclos?o, e para larvas foi avaliado o percentual de mortalidade. As formula??es oleosas de M. anisopliae s.l. e de B. bassiana foram mais eficazes sobre ovos, larvas e f?meas ingurgitadas de R. microplus do que as suspens?es aquosas. O isolado de M. anisopliae s.l. formulado em ?leo mineral causou altera??es significativas em todos os par?metros de f?meas ingurgitadas, entretanto, as formula??es oleosas do isolado de B. bassiana alteraram significativamente somente o ?ndice nutricional. Os isolados f?ngicos de M. anisopliae s.l. e B. bassiana formulados em ?leo mineral apresentaram percentual de controle de at? 93,69% e 21.67%, respectivamente, enquanto que o percentual de controle das suspens?es aquosas de M. anisopliae s.l. e B. bassiana foi de 18,70% e 1,72%, respectivamente. No tratamento de ovos, as formula??es oleosas de M. anisopliae s.l. e B. bassiana causaram redu??o no percentual de eclos?o de at? 102,5 e 3,64 vezes, respectivamente. No bioensaio com larvas, as formula??es oleosas de M. anisopliae s.l. causaram um percentual de mortalidade pr?ximo a 100% no quinto dia ap?s o tratamento, enquanto que as formula??es de B. bassiana atingiram este percentual somente no 20? dia ap?s o tratamento. Os grupos controle contendo ?leo mineral causaram mortalidade de larvas a partir do 15? dia ap?s o tratamento, indicando um poss?vel efeito t?xico do ?leo sobre este est?gio de R. microplus. Os resultados demonstram que o isolado Ma 959 de M. anisopliae s.l. foi mais virulento para f?meas ingurgitadas, ovos e larvas de R. microplus do que o isolado Bb 986 de B. bassiana. As formula??es oleosas dos fungos testados foram mais eficazes do que as suspens?es aquosas. O ?leo mineral utilizado nas concentra??es de 10%, 15% e 20% potencializa a a??o dos isolados Ma 959 de M. anisopliae s.l. e Bb 986 de B. bassiana contra o carrapato R. microplus, podendo ser utilizado como adjuvante em formula??es oleosas.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2018-08-28T18:22:19Z No. of bitstreams: 1 2016 - Allan Felipe Marciano.pdf: 1368631 bytes, checksum: bba1066f388233008b1c3f41343d33e2 (MD5) / Made available in DSpace on 2018-08-28T18:22:19Z (GMT). No. of bitstreams: 1 2016 - Allan Felipe Marciano.pdf: 1368631 bytes, checksum: bba1066f388233008b1c3f41343d33e2 (MD5) Previous issue date: 2016-10-03 / CAPES / CNPq / The tick Rhipicephalus microplus has been considered the most important parasite in cattles. It causes economic lost in dairy and beef cattle. As the fungus Metarhizium spp, a promising biocontrol agent, with remarkable virulence and efficacy against this arthropod. Environmental conditions can directly influence entomopathogenic fungal activity when it is released on the field. Therefore, adjuvants should be used to enhance fungal pathogenicity, stability and viability under unfavorable environmental conditions. Accordingly, several oily vehicles have been studied as adjuvant components. The present study aimed at investigate under semi-natural conditions, the permanence of fungi in the soil, the pathogenicity and the efficacy of two isolates of Metarhizium anisopliae sensu latu (ARSEF 3641 and CG 148) formulated in oil (soy and mineral), on engorged females of R. microplus engorged. The fungus was mass produced on rice cultivation and the semi-natural environment was framed from pots with Brachiaria brizantha cv. Marandu. The experiment was compound of seven groups: Control OLV (treated with vegetable oil and 0,1% of tween 80), Control OLM (treated with mineral oil and 0,1% of Tween 80), Treated 3641 OLV (treated with isolated ARSEF 3641 + vegetable oil); Treated 3641 OLM (treated with ARSEF 3641 isolated + mineral oil); Treated CG 148 OLV (treated with CG148 isolated + vegetable oil); Treated CG 148 OLM (treated with CG 148 isolated + mineral oil). Each group contained ten pots. The soil of each pot was sprayed with 80 ml of formulation at 108 conidia/ml in accordance with the proposed group. Afterwards, 5 engorged females were put on each pot. All pots were daily inspected for evaluating the percent mortality of famales. The efficacy of formulations tested was obtained by comparison of the number of live larvae collected at the apex of forage leaves of the control groups with the number of larvae from the treated groups. The collection of larvae was held on the 7th, 14th and 21st after the hatch. To evaluate the presence of Metarhizium spp. in the soil, a methodology was established to quantify the colonies number found in samples collected from each pot before the spraying and at 3th, 7th, 21th and 60th day after treatment. For the standardization of the methodology set out in the quantification of colonies in the soil, data from three evaluators were confronted by Kaapa test, the statistical analysis of data were submitted to the distribution of normality by the Shapiro-Wilk test. Data were analyzed as nonparametric and we used the Kruskal-Wallis test for analysis of variance followed by the Student-Newman-Keuls to compare the mean. The tested oil fungal formulations showed daily efficacy ranging between 85,08 and 96,13% compared to their respective controls. The group trated with isolated ARSEF 3641 formulated both in mineral oil and vegetable oil showed the better efficacy when compared to the respective control groups. Also, during tick females? laying period, it was possible to observe Metarhizium spp. externalization on R. microplus engorged females cuticle in all groups that were exposed to fungal formulations, confirming the ability of these fungal isolates on develop all growth stages over this arthropod in semi-natural conditions. Both fungal isolates formulated in vegetable or mineral oil showed to be able to remain active in semi-natural environment as they were pathogenic and effective against engorged females, and able to reduce significantly future generations of the tick. / O carrapato Rhipicephalus microplus ? considerado um dos principais agentes de parasitismo em bovinos por representar significativas perdas econ?micas na pecu?ria de leite e corte. Sendo o fungo Metarhizium spp, um promissor agente biocontrolador para este artr?pode, por apresentar grande virul?ncia e efic?cia contra este ectoparasita. Agentes microbianos quando lan?ados a campo, podem sofrer grande influ?ncia pelas intemp?ries ambientais, devendo estes receberem componentes que favore?am a sua patogenicidade, perman?ncia e viabilidade no ambiente, a fim de atingirem resultados satisfat?rios. Visto isto, diferentes ve?culos oleosos v?m sendo alvos de estudos como componentes adjuvantes. O objetivo deste trabalho foi investigar, sob condi??es seminaturais, a perman?ncia no solo, a virul?ncia e a efic?cia de dois isolados do fungo Metarhizium anisopliae s.l. (ARSEF 3641 e CG 148) formulados em ?leo (soja e mineral) sobre f?meas de R. microplus, assim como a taxa e recupera??o de larvas. O fungo foi produzido em massa a partir do cultivo dos isolados em arroz e para a forma??o do ambiente seminatural, sementes de Brachiaria brizantha, cultivar Marandu, foram plantadas em vasos de polipropileno. O experimento foi composto por sete grupos: Controle CTR (grupo sem tratamento); Controle OLV (tratado com ?leo vegetal e Tween 80 a 0,1%), Controle OLM (tratado com ?leo mineral e Tween 80 a 0,1%), Tratado 3641 OLV (tratado com o isolado ARSEF 3641 + ?leo vegetal + Tween 80 a 0,1%); Tratado 3641 OLM (tratado com o isolado f?ngico ARSEF 3641 + ?leo mineral + Tween 80 a 0,1%); Tratado CG 148 OLV (tratado com o isolado 148 + ?leo vegetal + Tween 80 a 0,1%); Tratado CG 148 OLM (tratado com o isolado CG 148 + ?leo mineral + Tween 80 a 0,1%). Cada grupo conteve dez vasos. Foram pulverizados sobre a superf?cie do solo de cada vaso, 80ml da formula??o a 108 con?dios/ml de acordo com o grupo proposto para cada formula??o e posteriormente 5 f?meas ingurgitadas de peso m?dio e homog?neo foram adicionadas em cada vaso. Os mesmos foram vistoriados diariamente para a avalia??o da mortalidade das f?meas. O percentual de efic?cia das formula??es dos isolados testados foi obtido a partir da compara??o entre o n?mero de larvas vivas coletadas no ?pice das folhas da forrageira dos grupos controles e dos grupos tratados. A coleta de larvas foi realizada no 7?, 14? e 21? ap?s a eclos?o das mesmas. Para a avalia??o da presen?a de Metarhizium spp. no solo, foi estabelecido e validada uma metodologia para a quantifica??o do n?mero de col?nias encontradas em amostras coletadas de cada vaso antes da pulveriza??o e no 3?, 7?, 21? e 60? dia ap?s o tratamento. A valida??o do m?todo se fez pelo confronto da avalia??o de tr?s observadores utilizando o teste Kaapa. Para a an?lise estat?stica dos demais dados, os mesmos foram submetidos ? distribui??o da normalidade pelo teste de Shapiro-Wilk sendo classificados como n?o param?tricos e foi utilizado o teste de Kruskal Wallis para an?lise de vari?ncia, seguido do Student-Newman-Keuls para compara??o entre as ordena??es m?dias. Os grupos tratados com as formula??es f?ngicas oleosas apresentaram efic?cia m?dia no controle de R. microplus variando entre 85,08 e 96,13% em rela??o aos seus respectivos grupos controles durante o per?odo de avalia??o do n?mero de larvas infestantes. O isolado ARSEF 3641 formulado tanto em ?leo vegetal quanto em ?leo mineral apresentou os melhores percentuais de efic?cia. Durante o per?odo de postura das f?meas, foi poss?vel encontrar a exterioriza??o de Metarhizium sp. nas mesmas em todos os grupos tratados com as formula??es f?ngicas, confirmando a capacidade dos isolados f?ngicos em se manterem e realizarem todas as fases de desenvolvimento sobre o artr?pode em condi??es seminaturais. Ambos os isolados testados, nas duas condi??es de formula??es propostas, mostraram-se aptos a permanecerem ativos no ambiente seminatural, virulentos e eficazes contra f?meas de R. microplus, sendo capazes de reduzir significativamente gera??es futuras do carrapato.

Until 2014, scientific knowledge on the diversity of Chilean Ixodoidea summarized 19 species and only agents of Borrelia and Rickettsia genera had been detected. The objectives of this study were to evaluate the occurrence of further agents of Anaplasma, Borrelia, Coxiella, Ehrlichia, Rickettsia and Hepatozoon by means of molecular tools. Obtained sequences were inserted into a phylogenetic context in order to evaluate their relatedness to microorganisms of know pathogenic roles. As agents of Coxiella genus resulted to be related to endosymbiotic bacteria, data on these organisms was used to perform a taxonomic study with ticks of the Ornithodoors capensis sensu lato complex. The results confirm that Chilean ticks harbor at least three new borrelial, one new rickettsial, and three new Hepatozoon species for science. Moreover, Rickettsia amblyommatis, Rickettsia hoogstraalii and Rickettsia lusitaniae are added to the list of Chilean rickettsiae. Although ticks were positive to Anaplasmataceae PCRs, an accurate study including longer fragments of the 16S RNA targeted gene must be performed in order to confirm their specific identity. Coxiella-like endosymbionts are specific of every of the four O. capensis s. l. species analyzed in this study, and therefore constitute a useful tool in order to confirm the identities and define genetic boundaries of ticks of this group in South America. Finally, the results of this study add at least five new species of Argasidae family into Chilean fauna of ticks, and point the occurrence of several forms that need further assessment in order to accurately confirm their identities. / Até 2014, o conhecimento científico sobre a diversidade de Ixodoidea no Chile estava representado por 19 espécies e apenas agentes infecciosos dos gêneros Borrelia e Rickettsia haviam sido descritos. O objetivo deste estudo foi o de avaliar a ocorrência de outros patógenos transmitidos por carrapatos por meio de técnicas moleculares orientadas para a deteção de Anaplasma, Borrelia, Coxiella, Ehrlichia, Rickettsia e Hepatozoon. As sequências obtidas foram analisadas filogeneticamente, identificando-se suas posições em comparação à de organismos de papeis patogénicos já conhecidos. Como os agentes do gênero Coxiella apresentaram proximidade filogenética em relação a bactérias congenêricas endosimbiontes, os dados sobre estas foram utilizados para realizar um estudo taxonômico em carrapatos do complexo Ornithodoros capensis sensu lato. Em geral, os resultados confirmam a presença de pelo menos três novas espécies de Borrelia, uma nova Rickettsia, e três novas espécies de Hepatozoon para a ciência. Rickettsia amblyommatis, Rickettsia hoogstraalii e Rickettsia lusitaniae foram inseridas como novos agentes associados a carrapatos no Chile. Embora alguns carrapatos fossem positivos para a presença de bactérias da família Anaplasmataceae, futuros estudos devem ser desenvolvidos para confirmar a sua condição especifica, especialmente através da obtenção de maiores fragmentos do gene codificante para RNA 16S. Os organismos tipo Coxiella são específicos para cada uma das quatro espécies de carrapatos do grupo O. capensis analisados neste estudo. Portanto, constituem uma ferramenta de valor taxonômico para confirmar as identidades e limites genéticos destes. Finalmente, os resultados deste estudo adicionam pelo menos cinco novas espécies de carrapatos para a família Argasidae no Chile e apontam a ocorrência de várias morfotipos de condição incerta que precisam de maiores análises para esclarecer a com certeza a sua posição taxonômica.

Orientador: Maria Izabel Souza Camargo / Resumo: O presente trabalho teve como objetivo avaliar o efeito tóxico e terapêutico do extrato da glândula salivar (EGS) de fêmeas de carrapatos Rhipicephalus sanguineus senso lato (Acari: Ixodidae), alimentadas por 2 dias em hospedeiros, em diferentes concentrações, por meio de injeções intraperitoneais em ratas Wistar. Os resultados clínicos mostraram que na concentração de 10 μg/μL houve aumento da frequência de neutrófilos e diminuição da de linfócitos. Na análise histológica do fígado, observou-se que o extrato nessa concentração causou alguns efeitos tóxicos como vacuolização citoplasmática nos hepatócitos e desorganização estrutural dos cordões celulares. Nas concentrações de 40 e 80 μg/μL, as ratas ganharam peso corporal e tiveram o peso relativo do fígado diminuído, evidenciandoo que essas concentrações causaram toxicidade sistêmica. Nesse trabalho foi também analisado o efeito do EGS apenas na concentração de 0,04μg/μL, sobre lesões pré-neoplásicas (LPN) no fígado de ratos Wistar e observou-se aumento no peso relativo apenas do fígado nos animais dos grupos LPN e LPN+EGS quando comparados ao controle. A histologia mostrou que os animais LPN, antes da injeção do extrato, foram os que tiveram o tecido hepático com maiores danos (desorganização dos cordões, aumento de tecido conjuntivo, vacuolização citoplasmática, células apoptóticas e aumento na frequência de células de Kupffer, células de defesa deste órgão) os quais foram reduzidos quando os ratos receberam o EGS. No pres... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study aimed to evaluate the toxic and pharmacological effect of salivary gland extract (SGE) of female ticks Rhipicephalus sanguineus in different concentrations through intraperitoneal injections in Wistar rats. Clinical results showed that at the concentration of 10 μg/μL there was an increase in neutrophil frequency and a decrease in lymphocytes. It was also observed that in the liver histological analysis, the extract at this concentration caused some toxic effects: cytoplasmic vacuolization in the hepatocytes and structural disorganization in the cellular cords. At concentrations of 40 and 80 μg/μL, rats body weight increased, and relative liver weight decreased, showing that these concentrations caused systemic toxicity. In this study, was analysed the effect of SGE in the concentration of 0.04 μg/μL on the pre-neoplasic lesions (PNL) in the liver of Wistar rats, and there was an increase in the relative weight of the liver in the groups PNL and PNL + SGE. The histology showed that the PNL animals had the hepatic tissue with the biggest damage (cord disorganization, increase of connective tissue, cytoplasmic vacuolization, apoptotic cells and increased Kupffer cell quantity, indicating immune response), those alterations were reduced when the mice received the SGE as treatment. In the study about the in vitro evaluation of the acaricides effect of thymol and carvacrol on RML-15 cells from R. sanguineus s.l. ticks were carried out. Thymol at all tested concentration... (Complete abstract click electronic access below) / Doutor

Taiwan Security Market is a typical order-driven market, and the business transactions are matched through the electronic trading system since 1988. In this work, we study the joint distributions of tick size changes of bid price and ask price, bid volume, and ask volume¡@for each matching order in Taiwan Stock Exchange (TSEC). Exponentially weighted moving average (EWMA) method is adopted to update the joint distribution of the incoming order variables aforementioned. Here we propose five methods to determine the update timing and consider three different initial matrices of the joint distributions. In empirical study, the daily matching data of two enterprises Uni-president Enterprises Corporation and Formosa Plastics Corporation in April, 2005 are considered. The goodness of fit for the joint distributions are determined by Chi-square Goodness of Fit Test. The results show that EWMA method provide good fit for most of the daily transaction data.

In this paper, we investigate the problem of estimating the autocorrelation of squared returns modeled by diffusion processes with data observed at non-equi-spaced discrete times. Throughout, we will suppose that the stock price processes evolve in continuous time as the Heston-type stochastic volatility processes and the transactions arrive randomly according to a Poisson process. In order to estimate the autocorrelation at a fixed delay, the original non-equispaced data will be synchronized. When imputing missing data, we adopt the previous-tick interpolation scheme. Asymptotic property of the sample autocorrelation of squared returns based on the previous-tick synchronized data will be investigated. Simulation studies are performed and applications to real examples are illustrated.

SUMMARY Assessment of health care services quality and accessibility for tick-borne encephalitis patients in Kaunas region Liucijus Ambraška Supervisor Janina Petkevičienė, Dr.Sc.Assoc. Prof., Department of Social Medicine. Faculty of Public Health, Kaunas University of Medicine.- Kaunas, 2005.-P.68 Key words: tick-borne encephalitis, quality and accessibility of health care services Incidence of tick-borne encephalitis (TBE) is increasing by data of Lithuanian health information center. Aim of the study – to assess accessibility and quality of health care services for TBE patients in Kaunas region. Objectives: to establish peculiarities of transmission TBE infection and opinion about TBE prophylaxis of reconvalescents; to evaluate duration of admission period of TBE patients to specialized hospital and peculiarities of monitoring after discharging and satisfaction with health care services; to determine standpoint of general practitioners (GP) on TBE prophylaxis and reconvalescents monitoring problems. Methods. Case histories of TBE patients treated in Kaunas Clinical Hospital of Infectious Diseases in years 2001-2002 (n=187) analyzed. Questionnaires about state of health and assessment of quality of health care services during period of illness and reconvalescence were posted. 104 answers received. Questionnaires about standpoint on TBE control problems handed to 150 GP and returned by 101. Original questionnaires used. Differences between groups assessed using Mann-Whitney... [to full text]

The main objective oft his dissertation was to identify the causes of the rise of the tick population in KwaZulu-Natal in 1999. After 100 years of intensive chemical tick control, tick numbers remain high and the stock losses caused by tick borne diseases are still significant. In South Africa legislation was introduced to support intensive chemical tick control. Ticks have consistently shown themselves to possess a genetic pool containing the potential to resist a wide range of chemical poisons. The introduction of new chemicals followed by widespread use, has often resulted in the appearance of a tick population resistant to those chemicals. The problem is compounded by the fact that some farmers are also found to be helping ticks to multiply by not following instructions given by the chemical industry on how to use dips. Chemicals which are used to control ticks are also beyond the financial means of many cattle owners especially in resource- poor communities. Apart from the high cost of intensive tick control, the chemicals that are used to destroy ticks are very poisonous, not only to ticks but to the birds which are natural predators of ticks. The negative effects of these chemicals on the environment combined with the high cost of tick control has forced a revision of intensive chemical tick control strategy. There is now a shift to use methods of tick control which are friendly to the environment and affordable to the resource-poor communities. This dissertation provides a historical overview of the problem in KwaZulu-Natal and recommendations on how to deal with the problem in future. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001.

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains xv, 126 p.; also includes graphics (some col.). Includes bibliographical references (p. 96-107). Available online via OhioLINK's ETD Center

Rhiphicephalus microplus is one of the main ectoparasites of cattle in regions of tropical and subtropical climate. The economic losses caused by this parasite are related to treatment costs, decreased productivity and disease transmission. Currently the use of chemical products is still the most common form of control of the cattle tick, however, its use in an inadequate and suppressive way, has been causing the development of resistance to different classes of commercially available acaricides. Thus, the control of this parasite has been characterized by presenting a great challenge for technicians and producers. An alternative to tick control is the association of two different pharmacological bases, and currently this form of presentation is widely found commercially. The objective of this work is to describe the evaluation of the effectiveness of organophosphates and synthetic pyrethroids based on different combinations of R. microplus in the state of Rio Grande do Sul, Brazil. For this, 54 samples of cattle farms were collected, located in different municipalities of the state of Rio Grande do Sul. The evaluation of the in vitro efficacy of the acaricides tested was performed through the adult immersion test (AIT). In order to carry out the tests, four commercially available products were chosen: Ectoparasiticide A - 15% cypermethrin + 25% chlorpyrifos + 1% citronellal - (Colosso®, Ouro Fino Animal Health), Ectoparasiticide B - 15% cypermethrin + 30% chlorpyrifos + 15% fenthion - (Colosso FC30®, Ouro Fino Animal Health), Ectoparasiticide C - 50% chlorpyriphos + 6% cypermethrin high-cis - (Flytion®, Clarion Biosciences Ltda.) and Ectoparasiticide D - 16% ethion + 8.5% chlorpyriphos + 5% alpha-cypermethrin - (Potenty®, MSD Animal Health). The cypermethrin/ chlorpyrifos/ fenthion combination showed the best results, with an average efficiency greater than 95%, being effective in 94.44% (51/54) of the tested farms. The product containing the cypermethrin / chlorpyrifos / citronellal combination had a lower mean efficacy (62.11%), being effective in only 29.62% (16/54) of the properties tested. R. microplus presents different degrees of resistance to the association of organophosphates and synthetic pyrethroids, and multiple resistance was observed in most of the populations studied. Only the cypermethrin/ chlorpyrifos/ fenthion combination showed acceptable mean levels of efficacy in the tick populations studied. In this way, it is essential to establish a frequent monitoring of the effectiveness of the carrapaticides used, in order to prolong their useful life, contributing to their rational use for tick control in cattle. / Rhiphicephalus microplus é um dos principais ectoparasitas de bovinos em regiões de clima tropical e subtropical. As perdas econômicas que este parasita causa, estão relacionadas aos custos com tratamento, diminuição da produtividade e transmissão de doenças. Atualmente o uso de produtos químicos ainda é a forma mais comum de controle do carrapato bovino, no entanto, seu uso de maneira inadequada e supressiva, vem causando o desenvolvimento de resistência às diferentes classes de acaricidas disponíveis comercialmente. Assim, o controle deste parasita tem se caraterizado por apresentar um grande desafio para técnicos e produtores. Uma alternativa ao controle do carrapato é a associação de duas bases farmacológicas diferentes, sendo que atualmente esta forma de apresentação é amplamente encontrada a nível comercial. O objetivo deste trabalho é descrever a avaliação da eficácia de associações carrapaticidas, a base de organofosforados e piretroides sintéticos, em diferentes populações de R. microplus no estado do Rio Grande do Sul, Brasil. Para isto, foram coletadas amostras de carrapatos de 54 propriedades, localizadas em diferentes municípios do estado do Rio Grande do Sul. A avaliação da eficácia in vitro dos acaricidas testados foi realizada através do teste de imersão de teleóginas (bicarrapaticidograma). Para a realização dos testes, foram escolhidos quatro produtos comercialmente disponíveis, sendo eles denominados: Produto A - 15% cipermetrina + 25% cloripirifós + 1% citronelol - (Colosso®, Ouro Fino Saúde Animal), Produto B - 15% cipermetrina + 30% cloripirifós + 15% fenthion - (Colosso FC30®, Ouro Fino Saúde Animal), Produto C - 50% cloripirifós + 6% cipermetrina high-cis - (Flytion®, Clarion Biosciences Ltda.), Produto D - 16% ethion + 8.5% cloripirifós + 5% alfa-cipermetrina - (Potenty®, MSD Saúde Animal). A associação de cipermetrina/clorpirifós/fenthion, apresentou os melhores resultados, com eficácia média superior a 95%, sendo eficaz em 94,44% (51/54) das propriedades testadas. O produto contendo a associação de cipermetrina/clorpirifós/citronelal, apresentou menor eficácia média (62,11%), sendo eficaz em apenas 29,62% (16/54) das propriedades testadas. R. microplus, apresenta diferentes graus de resistência à associação de organofosforados e piretroides sintéticos, sendo observado resistência múltipla em boa parte das populações estudadas. Apenas a combinação de cipermetrina/clorpirifos/fenthion apresentou níveis médios aceitáveis de eficácia nas populações de carrapato estudadas. Desta maneira, é fundamental estabelecer um monitoramento frequente da eficácia dos carrapaticidas utilizados, a fim de prolongar sua vida útil, contribuindo para o seu uso racional para o controle do carrapato em bovinos.