Thesis (Ph.D.)--Aberdeen University, 2008. / Title from web page (viewed on March 9, 2009). Includes bibliographical references.

A normalised cDNA library was constructed from the synganglia of unfed adult <i>R. sanguineus.  </i>Of interest from a drug discovery perspective were ESTs encoding a chitinase enzyme and four transmembrane receptors including two glutamate-gated chloride receptors, a leucokinin-like receptor and a nicotinic acetylcholine receptor (nAChR) α subunit. The nAChR α subunit was chosen for further study.  This is the first identified full-length arachnid nAChR subunit.  Phylogenetically it is most similar to insect α1 nAChR group and has been called Rsα1.  This subunit is expressed in larval, nymphal and adult stages and within partially fed adult females.  <i>Rsα1 </i>was most abundant in the synganglion and also present in Malpighian tubules and oviduct yet was undetected in the salivary glands and gut tissues.  Using two-electrode voltage clamp in <i>Xenopus laevis </i>oocytes, Rsα1 did not functionally express as a homomer or when co-expressed with the vertebrate chicken β2 subunit using either RNA or DNA.  Chimeric constructs consisting of the tick N-terminal and the transmembrane portion of the <i>D. melanogaster </i>α2 nAChR (Dα2) (Rsα1-Dα2) and vice-versa were prepared.  Responses to acetylcholine were obtained from the Dα2-Rsα1 chimera showing that the Rsα1 nAChR can form a functional pore region.  However, no responses were obtained from the Rsα1-Dα2 chimera.  This preliminary data suggests that the Rsα1 nAChR cannot form a functional ligand binding region when expressed in Xenopus oocytes. The present study has proven that the tick synganglion is a rich source of transmembrane receptor targets for exploitation in future drug discovery.

Orientador: Rosemeire Cristina Linhari Rodrigues Pietro / Coorientador: Flávio Politi / Banca: Ilio Montanari Junior / Banca: Luis Vitor do Sacramento / Resumo: O Brasil é um dos maiores exportadores de carne bovina do mundo, entre 2003 e 2008 a receita com exportações cresceu de um bilhão para mais de cinco bilhões de dólares. Apesar disso, o setor enfrenta perdas consideráveis devido à ocorrência de infestações massivas de ectoparasitas como os carrapatos da espécie Rhipicephalus (Boophilus) microplus. Ainda dentro do agronegócio, outra produção que se encontra em amplo crescimento e demonstrando grande potencial de ganho de espaço no mercado internacional é a ovinocultura, com rebanho estimado em 14 milhões de animais, colocando o Brasil em 18º lugar no ranking mundial de exportações. Porém, existem grandes perdas econômicas devido à existência de infestações com endoparasitas, como o nematódeo gastrintestinail da espécie Haemonchus contortus. Em paralelo à preocupação com os prejuízos financeiros no agronegócio, outra espécie de carrapato, Rhipicephalus sanguineus, desperta interesse dos pesquisadores por ser o vetor de microrganismos causadores de importantes doenças em cães nas regiões tropicais e subtropicais. Devido ao mau uso, acaricidas e nematicidas sintéticos tem ocasionado o fenômeno de resistência, com isso a busca por novas substâncias a partir de espécies vegetais configura-se numa alternativa muito promissora para o controle desses parasitas. A espécie Achyrocline satureioides (Lam.) D.C. (Asteraceae), popularmente conhecida como macela, possui em sua composição compostos fenólicos, sobretudo flavonóis e flavanonas, ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Brazil is one of the largest beef exporter in the world and between 2003 and 2008, revenue from exports grew from one billion to more than five billion dollars. Nevertheless, the sector is facing considerable losses due to the occurrence of massive infestations of ectoparasites such as tick species of Rhipicephalus (Boophilus) microplus. In the agribusiness, another production that is in ample growth and showing great potential for space gain in the international market is the sheep industry, with herd estimated at 14 million animals, placing Brazil in 18th position in the world exports ranking. However, there are great economic losses due to the infestations of endoparasites, such as the gastrointestinal nematodes species of Haemonchus contortus. In parallel to the concern about the financial losses in agribusiness, other tick species, Rhipicephalus sanguineus, arouses interest of researchers for being the vector of microorganisms that causes major diseases to dogs in tropical and subtropical regions. Due to misuse of synthetic antiparasitic, which causes the phenomenon of resistance to them, the search for new substances from plant species sets up a very promising alternative for the biological control. The species Achyrocline satureioides (Lam.) DC (Asteraceae), popularly known as macela, has in its composition phenolic compounds, particularly flavonols and flavanones in the inflorescences. Based on the aspects, this study aimed to analyze the effectiveness of extractives of the first Brazilian cultivar of A. satureoides developed in the CPQBA on ticks R. (B.) microplus and R. sanguineus, as well as on the nematode H. contortus, using in vitro assays. The essential oil and the extracts of inflorescences of macela have shown that this plant has high activity on engorged females of R. (B.)... (Complete abstract click electronic access below) / Mestre

Orientador: Gervásio Henrique Bechara / Banca: Gustavo Seron Sanches / Banca: Gilson Pereira de Oliveira / Banca: Maria Izabel Camargo Mathias / Banca: Beatriz Rossetti Ferreira / Resumo: O controle de carrapatos à base de acaricidas químicos tem levado a seleção de ectoparasitos resistentes além de contaminação ambiental e de produtos de origem animal. Frente a isso, há crescente incentivo na busca por alternativas de controle do ectoparasito, como o desenvolvimento de vacinas. O presente estudo teve como objetivo avaliar a utilização de uma proteína recombinante da aquaporina do Rhipicephalus (Boophilus) microplus como antígeno em uma vacina contra R. sanguineus, em cães domésticos. A investigação foi realizada em cooperação científica com o United States Department of Agriculture/Agricultural Research Service (USDA/ARS). Os efeitos da vacina foram avaliados nos diferentes estádios do ectoparasito em cães previamente vacinados com o antígeno + adjuvante (Montanide) (G1) e em animais de um grupo controle inoculados apenas como adjuvante (G2). Foram avaliados: i. potencial biótico (parâmetros biológicos) dos carrapatos; ii. Título de anticorpos séricos (IgG) de cães por meio do ensaio imunoenzimático indireto (Teste ELISA) pós imunização; iii. Avaliação histopatológica do sitio de fixação dos carrapatos em diversos momentos pós-fixação na pele dos hospedeiros, incluindo a contagem de células inflamatórias migradas para o foco inflamatório; iv. Histologia do ovário dos carrapatos para observação de possíveis danos causados pela ação do imunógeno; v. locais de ação do antígeno no corpo do carrapato por meio de ensaio imunohistoquímico. Os principais resultados o... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Tick control based on chemical acaricides has led to rapid selection of resistant ectoparasites as well as environmental and animal products contamination. Therefore, there is an increasing incentive in the search for alternatives to the parasite's control, such as the development of vaccines. This study aimed to evaluate the use of a recombinant aquaporin R.(Boophilus) microplus protein as antigen in a vaccine against R. sanguineus in domestic dogs. The research was conducted on scientific cooperation with the United States Department of Agriculture / Agricultural Research Service (USDA / ARS). The vaccine's effects were evaluated at different stages of the ectoparasite in dogs previously vaccinated with antigen + adjuvant (Montanide) (G1) and in animals of a control group inoculated only with adjuvant (G2). It was evaluated: i. biotic potential (biological parameters) of ticks; ii. serum antibodies (IgG) titers of the dogs after immunization, by indirect enzymelinked immunosorbent assay (ELISA); iii. Histopathological evaluation of the tick's attachment site at various times post-fixation on the host's skin, including the inflammatory cell counts migrated into the inflammatory site; iv. Tick's ovarian histology for observation of possible damage caused by the action of the immunogen; v. possible antigen action sites in the tick's body by immunohistochemical assay. The main results were: 1) The engorgement period of adult females from the immunized group was 12% lower than the control group; 2) Larvae from the immunized group had 8.7% higher engorgement period than the control group and weighed 7.2% less; 3) Nymphs from the immunized group had 4.5% lower engorgement period and weighed 3.6% less than the control group; 4) Although the animals showed increased antibodies titer post-second immunization, these titers decreased rapidly; 5) The (Complete abstract click electronic access below) / Doutor

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2018-02-28T16:12:09Z No. of bitstreams: 2 Tese - Jaires Gomes de Oliveira Filho - 2018.pdf: 1814554 bytes, checksum: 3897a940820688b6672b09b6a409c4b8 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-02-28T16:12:35Z (GMT) No. of bitstreams: 2 Tese - Jaires Gomes de Oliveira Filho - 2018.pdf: 1814554 bytes, checksum: 3897a940820688b6672b09b6a409c4b8 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-02-28T16:12:35Z (GMT). No. of bitstreams: 2 Tese - Jaires Gomes de Oliveira Filho - 2018.pdf: 1814554 bytes, checksum: 3897a940820688b6672b09b6a409c4b8 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-02-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Rhipicephalus sanguineus sensu lato, the "brown dog tick", preferentially parasite the domestic dog, in the latter can parasite others mammals species including humans. This tick demonstrates a hunting behavior by its host, being widely attracted by the bark and the CO2 among other signs related to the presence of its hosts. Despite being commonly found parasite on dogs, it is known that some breeds such as beagles are less parasitic than other breeds like English Cocker Spaniel which can present a parasitic load about up to 11.5 times higher than mongrel dogs. It is notable a capacity of ticks and other arthropods in their hosts in relation to desirable or undesirable characteristics that can perceive these by means of chemoreception of volatile compounds emanated by these hosts. This adaptive tool is called olfactory aposematism. Olfactory apostotism is capable of an ectoparasite in avoiding its hosts through a perception of a volatile chemical emanated by it that signals a negative adaptive response to the arthropod. Usually this response may be linked to immune factors, excessive grooming, inaccessibility or other factors. One of the big problems nowadays undoubtedly is the control of ticks and diseases that are transmitted to their hosts during the blood repast. One of the alternatives for control of parasitism in order to deter ticks from the search for their hosts is a use of compounds found in resistant hosts that are interpreted by these arthropods as non-hosts. These compounds demonstrate a more specific activity between arthropod parasites and their hosts, since they were selected during an adaptation between species involved in this parasite-host relationship forging bases of parasite selection by susceptible and resistant hosts. / Rhipicephalus sanguineus sensu lato, também conhecido como “carrapato marrom do cão”, parasita preferencialmente o cão doméstico, no entanto pode parasitar inúmeras outras espécies mamíferas inclusive seres humanos. Este carrapato demonstra um comportamento de busca ativa por seu hospedeiro, sendo amplamente atraído pelo latido e pelo CO2 e outros sinais relacionados a presença de seus hospedeiros. Apesar de parasitar preferencialmente cães sabe-se que algumas raças como o beagle são menos parasitadas que outras raças como Cocker spaniel inglês que podem apresentar uma carga parasitaria cerca de até 11,5 vezes maior que cães mestiços. É notável a capacidade de carrapatos e demais artrópodes tem em selecionar seus hospedeiros em relação a características desejáveis ou indesejáveis que conseguem perceber destes, por meio da quimiorrecepção de compostos voláteis emanados pelos hospedeiros. A esta ferramenta adaptativa damos o nome aposematismo olfativo que é capacidade de um de parasito em evitar seus hospedeiros mediante a percepção de um químico emanado por este que sinalize uma resposta adaptava negativa ao artrópode. Geralmente esta resposta pode estar ligada a fatores imunes, excesso de grooming ou inacessibilidade ou demais fatores. Um dos grandes problemas na atualidade sem dúvida e o controle de carrapatos e doenças que são transmitem a seus hospedeiros durante o repasto sanguíneo. Uma das alternativas para o controle de parasitismo afim de dissuadir os carrapatos da busca por seus hospedeiros é uma utilização de compostos encontrados em hospedeiros resistentes que são interpretados por estes artrópodes como não hospedeiros. Estes compostos demonstram atividade mais especifica entre artrópode parasitos e seus hospedeiros, pois foram selecionados durante uma adaptação entre espécies envolvidas nesta relação parasitohospedeiro forjando bases da seleção de parasitos por hospedeiros suscetíveis e resistentes.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-09-20T19:27:14Z No. of bitstreams: 1 fernandacalmon.pdf: 376302 bytes, checksum: f059fa7ccf2af6362e23df2ba62301fb (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-09-22T15:20:06Z (GMT) No. of bitstreams: 1 fernandacalmon.pdf: 376302 bytes, checksum: f059fa7ccf2af6362e23df2ba62301fb (MD5) / Made available in DSpace on 2017-09-22T15:20:06Z (GMT). No. of bitstreams: 1 fernandacalmon.pdf: 376302 bytes, checksum: f059fa7ccf2af6362e23df2ba62301fb (MD5) Previous issue date: 2013-02-07 / O presente estudo objetivou avaliar a toxicidade de diferentes solventes e do Tween 80 sobre os estágios imaturos de Rhipicephalus sanguineus e sobre larvas e ninfas ingurgitadas e ninfas não ingurgitadas de Amblyomma cajennense. Para larvas não ingurgitadas de R. sanguineus foi utilizado o teste de pacote de larvas modificado e a mortalidade foi avaliada após 24 horas. O mesmo teste foi adaptado para a realização do experimento com ninfas não ingurgitadas das duas espécies e nesses dois experimentos foram testados os solventes etanol, metanol e acetona puros e dimetilsufóxido e tween 80 na concentração de 50μl/ml. Em relação aos testes com larvas e ninfas ingurgitadas foi utilizada a metodologia de imersão e a mortalidade foi avaliada após 15 dias. Os solventes etanol, metanol e acetona foram testados nas concentrações de 50, 250, 500, 750 e 1000 μl/ml, enquanto que o solvente dimetilsufóxido e o surfactante Tween foram testados somente a 50μl/ml, no entanto, para A.cajennense o surfactante foi acrescido com a concentração de 25μl/ml para os estágios ingurgitados. Para cada teste foi feito um controle com água destilada. Foram feitas dez repetições por tratamento e os grupos experimentais foram mantidos em câmara climatizada (27±1°C e UR>80±10%). Para R. sanguineus a acetona se mostrou tóxica nos estágios ingurgitados na maior concentração, o etanol e metanol foram tóxicos na maior concentração apenas para larvas ingurgitadas; para as larvas ingurgitadas de A. cajennense o etanol, metanol e a acetona forma tóxicos na maior concentração e o Tween matou 52 e 80% das larvas para as concentrações de 25 e 50μl/ml respectivamente, já para ninfas ingurgitadas o metanol matou 17,4 e a acetona 100% quando testados em qualidade pura, as ninfas não ingurgitadas não demonstraram sensibilidade aos solventes testados. Quanto a observação preliminar sobre a presença de ectoparasitos em aves silvestres, foram examinadas 58 aves de 5 famílias com prevalência de 15,5% de ectoparasitos. / The present study aimed to evaluate the toxicity of different solvents and of Tween 80 in immature stages of Rhipicephalus sanguineus and in larvae and engorged and non engorged nymphs of Amblyomma cajennense. For non engorged larvae of R. sanguineus it was utilized the larval packet test modified and mortality was evaluated after 24 hours. The same test was adapted for non engorged nymphs of both species and in both assays were tested ethanol, methanol and acetone in its pure concentrations and dimethylsulphoxide and Tween 80 in a concentration of 50μl/ml. For engorged larvae and nymphs it was utilized the immersion test and mortality was available after 15 days. The solvents ethanol, methanol and acetone were testes at concentrations of 50, 250, 500, 750 and 1000 μl/ml, while dimethylsulphoxide and the surfactant Tween were tested at concentrations of 50μl/ml, however, in the assays with A.cajennense engorged stages, the surfactant was added with a concentration of 25μl/ml. Ten repetitions were made for each treatment and the experimental groups were maintained in a BOD incubator (27±1°C e UR>80±10%).For each test it was made a control group with distilled water. For R.. sanguineus acetone showed toxic effects in engorged stages at the higher concentration, ethanol and methanol were toxic at higher concentration only for engorged larvae; to engorged larvae of A. cajennense the ethanol, methanol and acetone were toxic in the higher concentrations and the Tween caused mortality of 52 and 80% of larvae in concentrations of 25 and 50μl/ml respectively, for engorged nymphs, methanol caused a mortality of 17,4 and acetone of 100% when tested in pure concentrations, the tested solvents did not show any effect in engorged nymphs. As a preliminary remark on the presence of ectoparasites in wild birds, 58 birds were examined from 5 families with a prevalence of 15.5% of ectoparasites.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2015-12-02T19:00:12Z No. of bitstreams: 1 laryssaxavieraraujo.pdf: 1452466 bytes, checksum: 171c39ef6b34539f22d4565011471c2b (MD5) / Rejected by Adriana Oliveira (adriana.oliveira@ufjf.edu.br), reason: Título: somente primeira letra da primeira palavra em maiúsculo e nomes próprios também. Palavras-chave: primeira letra de cada palavra em maiúsculo. Acrescentar uma em cada linha (não precisa colocar ponto e nem vírgula no final) on 2015-12-03T11:58:48Z (GMT) / Submitted by Renata Lopes (renatasil82@gmail.com) on 2015-12-03T13:09:46Z No. of bitstreams: 1 laryssaxavieraraujo.pdf: 1452466 bytes, checksum: 171c39ef6b34539f22d4565011471c2b (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2015-12-03T13:58:23Z (GMT) No. of bitstreams: 1 laryssaxavieraraujo.pdf: 1452466 bytes, checksum: 171c39ef6b34539f22d4565011471c2b (MD5) / Made available in DSpace on 2015-12-03T13:58:23Z (GMT). No. of bitstreams: 1 laryssaxavieraraujo.pdf: 1452466 bytes, checksum: 171c39ef6b34539f22d4565011471c2b (MD5) Previous issue date: 2015-02-12 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Substâncias de origem vegetal como óleos essenciais e seus componentes têm demonstrado potencial para serem empregados no controle de diferentes pragas, incluindo carrapatos. Entre essas substâncias destacam-se os monoterpenos timol e carvacrol e o fenilpropanóide eugenol, moléculas que já tiveram sua atividade evidenciada sobre os carrapatos Rhipicephalus microplus e Rhipicephalus sanguineus s.l., espécies de grande importância econômica. Apesar da ação isolada dessas substâncias sobre carrapatos ter sido demonstrada in vitro em diferentes trabalhos, até o momento não existem estudos sobre o efeito da combinação das mesmas e relato de possível ação sinérgica sobre ixodídeos. Também são escassos os trabalhos que avaliam a atividade dessas substâncias em ambientes naturais ou semi-naturais, visando controlar carrapatos com ações direcionadas sobre a fase não parasitária. Dessa forma, este estudo teve como objetivos, avaliar os efeitos das combinações dos monoterpenos timol e carvacrol e do fenilpropanóide eugenol sobre larvas de R. microplus e R. sanguineus s.l. e avaliar a atividade carrapaticida do timol sobre larvas de R. microplus em condições semi-naturais. O primeiro capítulo traz os resultados dos efeitos das combinações das substâncias sobre as larvas desses carrapatos e para esse fim, foi utilizado o teste de pacote de larvas. Primeiramente foi feito o cálculo de CL50 e em seguida essas substâncias foram testadas em associação ou isoladas em concentrações subletais. Para larvas de R. microplus foram observados valores de CL50 para o timol, carvacrol e eugenol de 1,53; 1,76 e 4,67 mg/mL, respectivamente, e sinergismo entre todas as nove combinações testadas. Os valores de CL50 do timol, carvacrol e eugenol observados para larvas de R. sanguineus s.l., foram de 2,98; 3,29 e 5,19 mg/mL, respectivamente, sendo esse o primeiro estudo a determinar a CL50 dessas substâncias para R. sanguineus s.l. Para esta espécie, oito misturas apresentaram efeito sinérgico e apenas a combinação de carvacrol+timol na concentração da CL50, apresentou efeito sinérgico moderado. No segundo capítulo foi observado, pela primeira vez na literatura, que o timol ao ser aplicado em mudas de Brachiaria decumbens infestadas artificialmente com larvas de R. microplus foi capaz de reduzir 11 significativamente a infestação por esse carrapato. As maiores concentrações (10, 15, 20, 25 e 30,0 mg/mL) ocasionaram eficácias acima de 95% e os valores encontrados para as CL50 e CL90 foram de 3,45 e 9,25 mg/mL, respectivamente. Conclui-se que associações entre timol, carvacrol e eugenol em concentrações subletais apresentam efeito sinérgico sobre larvas de R. microplus e R. sanguineus s.l. e que o timol apresenta potencial para redução de larvas de R. microplus em condições semi-naturais. / Substances of plant origin, such as essential oils and their components have demonstrated the potential to be used to control different pests, including ticks. Among these substances stand out monoterpenes thymol and carvacrol and the phenylpropanoid eugenol, molecules that already had their activity demonstrated against ticks Rhipicephalus microplus and Rhipicephalus sanguineus s.l., species of great economic importance. Despite the isolated action of these substances on ticks has been demonstrated in vitro in different papers, until now there are no studies on the effect of the combination of this substances and report of possible synergistic action on ticks. Also there are few studies that evaluate the activity of these substances in natural and semi-natural environments in order to control ticks with targeted actions on the non-parasitic phase. Therefore, this study aimed to evaluate the effects of combinations of monoterpenes thymol and carvacrol and phenylpropanoid eugenol on larvae of Rhipicephalus microplus and Rhipicephalus sanguineus s.l. and evaluate the insecticidal activity of thymol on larvae of R. microplus in semi-natural conditions. The first chapter presents the results of the effects of combinations of substances on the larvae of these ticks. For R. microplus larvae were observed LC50 values for the thymol, carvacrol and eugenol of 1.53; 1.76 and 4.67 mg/ml, respectively, and synergism between all combinations tested. The LC50 values of thymol, carvacrol and eugenol observed for larvae of R. sanguineus s.l., were 2.98; 3.29 and 5.19 mg/ml, respectively. This is the first work reporting the LC50 values of these three substances against R. sanguineus s.l. For this species, eight combinations showed synergistic effect and only the combination of carvacrol+thymol in the concentration of LC50, showed moderate synergism. In this study it was observed that the larvae of R. microplus were more sensitive to the tested substances and their combinations. In the second chapter it was observed for the first time that thymol when applied in Brachiaria decumbens seedlings artificially infested with larvae of R. microplus was able to significantly reduce the infestation by this tick. The highest concentrations (10, 15, 20, 25 and 30.0 mg/ml) resulted efficiencies above 95% and the values found for the LC50 and LC90 were 3.45 and 9.25 mg/ml, respectively. It is concluded that associations between thymol, eugenol and carvacrol at sublethal concentrations have a synergistic effect on larvae of R. microplus and Rhipicephalus sanguineus s.l. and thymol has the potential for reducing R. microplus larvae in semi-natural conditions.

Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2017-07-21T11:57:41Z No. of bitstreams: 1 camiladecarvalhodelmonte.pdf: 1177411 bytes, checksum: 4c465e5e1042ff32579c95910ef00b7e (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-08-08T17:55:36Z (GMT) No. of bitstreams: 1 camiladecarvalhodelmonte.pdf: 1177411 bytes, checksum: 4c465e5e1042ff32579c95910ef00b7e (MD5) / Made available in DSpace on 2017-08-08T17:55:36Z (GMT). No. of bitstreams: 1 camiladecarvalhodelmonte.pdf: 1177411 bytes, checksum: 4c465e5e1042ff32579c95910ef00b7e (MD5) Previous issue date: 2017-03-30 / Rhipicephalus sanguineus sensu lato (s.l.) é um carrapato de conhecida importância médico-veterinária, devido ao seu potencial na transmissão de patógenos e aos danos diretos aos hospedeiros, como espoliação sanguínea, estresse, alergias e dermatites. O controle desses parasitos baseia-se, principalmente, no uso de substâncias químicas sintéticas, que frequentemente trazem conseqüências como contaminação ambiental, intoxicação dos animais e seus tratadores, e seleção de linhagens de carrapatos resistentes. O timol, um monoterpeno aromático isolado inicialmente de plantas da família Lamiaceae, vem apresentando bons resultados no controle de R. sanguineus s.l. em testes in vitro. Para que seja utilizado como um carrapaticida, o timol necessita ser veiculado em uma formulação farmacêutica adequada, que apresente facilidade de aplicação, custo acessível e segurança para uso tópico. O objetivo deste trabalho foi avaliar, pela primeira vez, a atividade carrapaticida in vitro de duas formulações de uso tópico contendo diferentes concentrações de timol, sobre larvas e ninfas, ingurgitadas e não ingurgitadas, de Rhipicephalus sanguineus s.l.. Para tal, foram desenvolvidas duas formulações-base: uma emulsão óleo em água (O/A) e uma solução hidroalcoólica, contendo diferentes concentrações de timol (0,5 mg/mL a 20 mg/mL). Para os bioensaios foi adotado o teste de pacote de larvas modificado, no caso de larvas e ninfas não ingurgitadas, com avaliação da mortalidade após 24 horas; e o teste de imersão, para larvas e ninfas ingurgitadas, com avaliação da mortalidade após 15 dias. O grupo controle constituiu-se das formulações-base, sem timol. Foram feitas 10 repetições para cada tratamento. Nos testes com emulsão, foi alcançada taxa de mortalidade média de 94,2% com a concentração de 0,75 mg/mL em larvas não ingurgitadas. No caso de larvas ingurgitadas, houve mortalidade média de 95,0% na concentração de 5,0 mg/mL. Ninfas não ingurgitadas tratadas com a emulsão a 2,5 mg/mL atingiram taxa de mortalidade média de 83,3% e no teste com ninfas ingurgitadas, foi verificada média de 86,0% de mortalidade para a concentração de 5,0 mg/mL. Nos testes com a solução hidroalcoólica, a mortalidade média encontrada para larvas não ingurgitadas foi de 88,1% para a concentração de 2,5 mg/mL. Para larvas ingurgitadas, a maior taxa de mortalidade verificada foi de 25,0%, na concentração de 20 mg/mL; o teste com ninfas não ingurgitadas apresentou taxas de mortalidade de 91,0% na concentração de 1,0 mg/mL e no teste com ninfas ingurgitadas verificaram-se baixas taxas de mortalidade, com o valor máximo de 18,3% para 20 mg/mL. Além dos testes em carrapatos, foram realizados testes de estabilidade preliminar com o objetivo de verificar eventuais problemas nas formulações. A solução hidroalcoólica mostrou-se estável em todas as condições testadas, nas concentrações de 2,5 e 5,0 mg/ml; a emulsão O/A mostrou sinais de instabilidade precoce na concentração de 5,0 mg/ml, porém, na concentração de 2,5 mg/ml apresentou-se estável. Os resultados obtidos indicaram que o timol, quando incorporado às formulações propostas, apresentou aumento de sua atividade acaricida sobre larvas não ingurgitadas de R. sanguineus s.l. tratadas topicamente, quando comparado aos dados da literatura; e embora tenha havido variações na toxicidade entre diferentes estágios e formas (ingurgitadas/não ingurgitadas), estas formulações parecem ser promissoras para um futuro uso terapêutico. / Rhipicephalus sanguineus sensu lato (s.l.) is a tick with known medical and veterinary importance, due to its potential for transmission of pathogens as well as the direct damage caused to hosts, such as blood spoliation, stress, allergies and dermatitis. Control of these parasites is mainly based on the use of synthetic chemical substances, but these often have negative consequences, including environmental contamination, intoxication of animals and handlers/owners, and selection of resistant strains. Thymol, an aromatic monoterpene initially isolated from plants of the family Lamiaceae, has presented good results in controlling R. sanguineus s.l. in in vitro tests. For use as an acaricide, thymol needs to be carried in a suitable pharmaceutical formulation, allowing easy application, reasonable cost and safety for topical use. The objective of this work was to assess, for the first time, the in vitro acaricidal activity of two topical formulations, each with different concentrations of thymol, on larvae and nymphs, both engorged and non-engorged, of R. sanguineus sensu lato. For this purpose, two base formulations were prepared: an oil-in-water (O/W) emulsion and a hydroalcoholic solution, containing different thymol concentrations (0.5 mg/mL to 20 mg/mL). The formulations were analyzed by the larval packet test (modified) in the case of larvae and non-engorged nymphs, with evaluation of mortality after 24 hours; and by the immersion test for larvae and engorged nymphs, with evaluation of mortality after 15 days. The control group was exposed to the base formulations without thymol. There were ten repetitions of each treatment. In the tests with the emulsion, the best average mortality rate was 94.2%, with the concentration of 0.75 mg/mL for non-engorged larvae. In the case of the engorged larvae, the best average mortality was 95.0% at the concentration of 5.0 mg/mL. The average mortality of the non-engorged nymphs treated with the emulsion containing 2.5 mg/mL was 83.3% and in the test with engorged nymphs, the mean mortality was 86.0% for the concentration of 5.0 mg/mL. In the tests with the hydroalcoholic solution, the highest average mortality among the non-engorged larvae was 88.1% for the concentration of 2.5 mg/mL. In turn, for the engorged larvae, the highest mortality was 25.0%, at the concentration of 20 mg/mL, while the test with non-engorged nymphs produced a mortality rate of 91.0% at the concentration of 1.0 mg/mL and in the test with engorged nymphs the maximum mortality was 18.3% with a concentration of 20 mg/mL. Besides the tests with the ticks, preliminary stability tests were carried out to verify possible problems with the formulations. The hydroalcoholic solution remained stable under all the conditions analyzed, at concentrations of 2.5 and 5.0 mg/ml, while the O/W emulsion showed signs of early instability at the concentration of 5.0 mg/ml but not at the concentration of 2.5 mg/ml. The results obtained indicate that the acaricidal activity of thymol, when included in the proposed formulations, was enhanced against non-engorged larvae with topical treatment in comparison with data in the literature. Although there were variations in toxicity between the different stages and forms (engorged and non-engorged), these formulations are promising for future therapeutic use.

In impoverished and resource limited communities such as townships, and welfare organizations, areas such as living and sleeping spaces are sometimes shared with animals, and occasionally humans. Dogs play an integral role in our lives and have become part of the family. Therefore, it is probable that ectoparasites, such as ticks, that feed on dogs also feed on other vertebrates, thereby, transmitting pathogens. The primary aim of this study was to screen for the presence of tick-borne pathogens in dogs from welfare organisations and townships in Cape Town, with special focus on Ehrlichia and Babesia spp. The reason for this choice of subject is due to the fact that very few tick-borne infection studies have focused on resource limited communities. Furthermore, welfare organisations have continuously attracted awareness due to the amount of unrestricted work performed by veterinarians in communities with limited resources. Consequently, the topic was borne. A total of 126 blood samples and 509 ticks (adults and nymphs) were collected directly from dogs from four welfare organisations and two townships in Cape Town. Samples were collected from April to July 2014. The four welfare organisations where samples were collected included the Animal Anti Cruelty League welfare organisations in Epping and Bellville, the Lucky Lucy Foundation in Joostenberg Vlakte and The Emma Animal Rescue Society (TEARS), located in the Sunnydale area. Samples were also collected from the Asanda village and Nomzamo, two townships located just outside the Cape Town suburb, the Strand. DNA was extracted from blood and ectoparasites and screened for the presence of Ehrlichia, Anaplasma, Theileria and Babesia species infections using touchdown PCR and RLB hybridization assays. Genus and species-specific probes were used during hybridization in order to identify specific parasite infections in the blood samples and the tick samples pooled according to geographical origin and species. Forty six (36.5%) of the blood samples tested positive for tick-borne pathogen DNA. Of the positive blood samples, 17 (13.5%) were infected with Ehrlichia canis; 16 (12.7%) with Babesia rossi and four (3.2%) samples were infected with Babesia vogeli. Incidental infections were also detected, these included Ehrlichia ruminantium (n=6, [4.7%]), Theileria taurotragi (n=2, [1.6%]) and Anaplasma sp. Omatjenne (n=1, [0.8%]) infections. DNA detected from 10 samples (7.94%) hybridized only to the Ehrlichia/Anaplasma genus-specific probes and four samples (3.17%) hybridized only to the Theileria/Babesia genus-specific probes. None of these 14 samples hybridized to any of the species-specific probes. Collected Rhipicephalus sanguineus (n=457) and Haemaphysalis elliptica (n=52) ticks were grouped into 15 pools, representing both tick species according to specific collection locations. Since only two H. elliptica from Asanda and one R. sanguineus from TEARS were collected, these ticks were mixed in pools of the dominant species as they were too few for DNA extraction. Ticks were collected from the Nomzamo Township (R. sanguineus n=400), Asanda village (H. elliptica n=2; R. sanguineus n=42), TEARS (H. elliptica n=21; R. sanguineus n=1), and the Animal Anti Cruelty League in both Epping (R. sanguineus n=14), and Bellville (H. elliptica n=29), in Cape Town. Analysis by the RLB assay showed that 11 (73.3%) of the 15 tick pools representing both tick species were positive for at least one parasite species. All positive samples hybridized with the Ehrlichia/Anaplasma genus-specific probe. Three (20%) tick pools containing both tick species tested positive for Ehrlichia canis infection, two (13.3%) tested positive for Babesia rossi and Babesia vogeli DNA was identified in one (6.6%) tick pool. The Theileria/Babesia genus-specific probe hybridised in three (20%) tick pools. These three pools were comprised of both R. sanguineus and H. elliptica tick species. These tick pools also tested positive for a specific Babesia tick-borne pathogen. Tick-borne pathogen DNA could not be detected in four (26.6%) tick pools. The fore-mentioned tick-borne pathogen DNA detected in the dog blood samples, and the ectoparasites collected from the same dogs during this study, suggests that dogs play a large role in the endemicity of these pathogens / Environmental Sciences / M. Sc. (Life Science)