Trypanosomosis is a parasitic disease in man, domestic and wild animals and is of major economic importance in many parts of the world, particularly in Sub-Saharan Africa. Trypanosoma congolense, T vivax and T brucei brucei are the major pathogenic trypanosomes infecting cattle in sub-Saharan Africa. The parasite itself is not directly responsible for the disease, but rather causes illness through the release of pathogenic factors. One of the major pathogenic factors released by trypanosomes is proteinases. Trypanotolerant cattle produce antibodies against a trypanosomal proteinase, congopain, that inhibit congopain activity. Congopain thus has vaccine potential. This study describes the mapping of immunogenic epitopes of congopain to identify peptide regions of the protein that induce enzyme inhibitory antibodies for inclusion in a trypanosome vaccine. This vaccine approach targets the disease, rather than the parasite by focusing on a pathogenic factor. These peptides also have potential for use in diagnostic assays. Peptides from the catalytic domain of a trypanosomal cysteine proteinase, congopain, were selected using an epitope prediction program. Peptides selected were from the two forms of congopain called CP1 and CP2. Antibodies against peptide-carrier conjugates were produced in chickens. The antibodies recognised native congopain, recombinant CP2 and the recombinant catalytic domain (C2). This suggests that the peptides selected have promise for use in vaccines. The peptides were also used to determine whether they are natural immunogenic epitopes of CP2 and thus have potential for use in diagnostic assays. Antibodies in the sera from T. congolense infected cattle recognised all the peptides in an ELISA. Antibodies in the sera from C2-immunised, non-infected cattle recognised most of the peptides in an ELISA. In order to distinguish between T. congolense and T vivax infection, two different peptides from the C-terminal extensions of CP2 and vivapain were used in ELISA tests with sera from infected cattle. Although anti-peptide antibodies produced against the two C-terminal extension peptides were specific for their respective peptides, thereby indicating the discriminatory power of the peptides selected, there was cross-reactivity by the sera from T. congolense and T. vivax infected cattle. Optimal antibody binding peptide sequences of these two peptides need to be identified by testing modified sequences of these two peptides to improve the sensitivity of this assay. In addition to attempting to define the epitopes of congopain, preliminary studies to increase the immunogenicity of congopain were also undertaken. Alpha 2-macroglobulin is a natural host inhibitor of proteinases. Inhibition occurs by entrapment of an active proteinase within the alpha 2-macroglobulin cage. In addition, it has been demonstrated that antigen complexed with alpha 2-macroglobulin becomes more immunogenic, resulting in enhanced antigenic presentation of an entrapped antigen. This study reports the interaction between congopain and alpha 2-macroglobulin. The preliminary results of this study showing congopain-alpha 2-macroglobulin interaction could be used to explore the possibility of increasing the immunogenicity of congopain and congopain epitopes by complexing these to alpha 2-macroglobulin. Congopain epitopes complexed with alpha 2-macroglobulin could be used to form a peptide-based vaccine. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.

The protozoan parasite Trypanosoma congolense is one of the aetiological agents of African animal trypanosomiasis that is transmitted by the tsetse fly. The parasite causes nagana in animals and affects livestock throughout sub-Saharan Africa. The toxicity of available drugs and the emergence of drug resistant parasites have affected the treatment of trypanosomiasis. Control of the disease has also been difficult due to ineffective vector control and the potential of trypanosomes to express hundreds of antigenetically distinct proteins on their surface. Vaccination against trypanosomiasis has been thought to be a possible control method. Since a vaccine based on variable surface proteins of the parasite is unlikely, research has been directed towards the identification of invariant pathogenic factors of the parasite as potential targets for therapy. Congopain, the major cysteine protease of T. congolense has been implicated in the pathology of the disease. Antibodies against congopain are known to contribute to the mechanisms of natural resistance to trypanosomiasis known as trypanotolerance by neutralising the pathogenic effects of the enzyme. Oligopeptidase B (OpdB), a trypanosomal serine protease has also been associated as a pathogenic factor of the disease. It is released into the host’s circulation by dead or dying parasites and retains its catalytic activity since it is insensitive to host serum inhibitors. In the present study, the catalytic domain of congopain (C2) and the use of alpha-2-macroglobulin (α2M) as an adjuvant were investigated for their potential use in an anti-disease vaccine. α2-Macroglobulin has been used to varying degrees to target different antigens to cells of the immune system and enhance their immunogenicity. A previous study showed that antibodies raised in rabbits against C2 complexed to α2M gave a higher percentage inhibition than antibodies made using C2 mixed with Freund’s adjuvant. In the present study, goats were immunised with C2 complexed with α2M to confirm the enhanced immunogenicity of C2 and the production of anti-C2 antibodies with superior inhibitory properties. Following immunisation, goats were challenged with T. congolense (strain IL 1180) and showed sustained antibody production during the two month infection period. Goat antibodies made using C2 in complex with α2M inhibited the hydrolysis of hide powder azure by C2 by 96%. Maximum inhibition of the hydrolysis of azocasein was observed to be 63% and hydrolysis of Z-Phe-Arg-AMC by C2 was inhibited by 73%. In order to determine the vaccine potential of OpdB, protein was recombinantly expressed as a glutathione-S-transferase fusion protein in the pGEX expression system and purified by glutathione agarose affinity chromatography and molecular exclusion chromatography. Since a small yield of protein necessitated several rounds of expression and extensive purification, OpdB was subsequently expressed as a His-tagged fusion protein in the pET bacterial expression system. Recombinant protein was easily purified using nickel chelate affinity chromatography. Purified OpdB was used with alum for the immmunisation of mice to produce antibodies capable of inhibiting enzyme activity. Following immunisation, mice were challenged with T. congolense (strain IL 1180) and also showed sustained antibody production following two months infection. Since all mice died, the administration of OpdB conferred no protection; however, anti-OpdB mouse antibodies inhibited 86% of OpdB activity against the substrate Z-Arg-Arg-AMC. In addition immunised mice were observed to survive 40% longer than control mice as they had previously been immunised with OpdB and were able to mount a rapid immune response against this pathogenic factor during infection. In general it could be concluded that immunisation of goats with C2 in complex with α2M produced antibodies with superior inhibitory properties. The immunisation of mice with OpdB and alum also produced inhibitory antibodies and previous administration of OpdB enabled mice to mount a rapid immune response against OpdB during infection. Antibody mediated enzyme inhibition demonstrates the potential use of C2 and OpdB as vaccines that may contribute to the development of an effective anti-disease vaccine. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 4 uppsatser.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 132-145).

Cattle ticks and tick-borne infections (TBIs) undermine cattle health and productivity in the whole of sub-Saharan Africa (SSA) including Nigeria. In this West African country, two thirds of the cattle population are reared in the central-northern regions, kept under the traditional pastoral husbandry of Fulani herders. Under the Fulanis’ management, cattle are grazed extensively, being exposed to infestation by several tick genera (i.e. Amblyomma, Hyalomma, and Rhipicephalus spp., sub-genus Boophilus spp. included), vectors of the causative agents of the most important bovine TBIs in West Africa: anaplasmosis, babesiosis and ehrlichiosis (cowdriosis). Nevertheless, the Fulani pastoralists do not usually employ chemicals to control ticks in their cattle, merely relying on traditional methods (i.e. manual removal of the most conspicuous specimens). This approach, however, does not prevent cattle from being re-infested, leaving the animals challenged by a broad variety of other tick species, most of which are vectors of economically relevant TBIs. Knowledge of tick and TBIs occurrence is an essential pre-requisite to assist field diagnosis and devising effective control strategies for a given area. Existing information on tick infestation of cattle in Nigeria is rather out-dated, mostly derived from studies carried out in the south of the country. Similarly, all studies published to date on cattle TBIs in the country do not include any molecular analysis, being based instead on cytological and/or serological diagnostics. Therefore, the aim of the present thesis was to assess the presence of cattle ticks and TBIs occurring in an area of Central Nigeria (i.e. Plateau State). This is a densely populated area with traditionally managed cattle, where no acarides have historically been employed on livestock. The work undertaken herein firstly reviews the information available to date on ticks and TBIs known to be endemic in Nigerian cattle, identifying gaps present in the existing knowledge, leading to the rationale of this study. An initial survey was conducted documenting the tick species infesting cattle in Central Nigeria, in order to assess the infestation rate of surveyed animals at the time of the year when the tick load on the host is known to be most abundant (i.e. the wet season). The survey provided novel information on tick populations in cattle in Nigeria disclosing the presence of a broad variety of species, most of which are vectors of hazardous TBIs. In order to conduct a molecular diagnosis of the TBIs within the study area, a novel methodology was developed (i.e. reverse line blotting, RLB). The application of this approach was based on a thorough review of its application to the diagnosis of TBIs worldwide as well as in SSA. The optimisation of the RLB at the University of Edinburgh to enable the detection of a broad-spectrum of TBIs in Nigeria, caused by an array of five genera of microorganisms (i.e. Ehrlichia and Anaplasma, Theileria and Babesia, Rickettsia spp.) is presented. The assessment of the analytical sensitivity of this technique for the detection of Anaplasma marginale, a highly endemic tick-borne pathogen in SSA, demonstrated a detection threshold of ≥ 7 infected cells (keeping the limit of a natural infection). The occurrence of TBIs in cattle in the study area was assessed during a large-scale epidemiological survey through the application of the validated RLB. This study disclosed the occurrence of a high prevalence of several bovine TBIs in Central Nigeria, some of which are of great veterinary and zoonotic concern. The RLB enabled the detection of carrier status as well as of numerous multiple infections (69.5%, 95% CI: 65.5–73.6%). Based on the findings presented, endemic stability for highly prevalent haemoparasites (i.e. Theileria mutans, Theileria velifera, Theileria taurotragi, Anaplasma marginale, Ehrlichia species Omatjenne) is postulated, whereas a more instable epidemiological scenario is hypothesized for other microorganisms (i.e. Anaplasma centrale and Babesia bovis), which might be connected with outbreaks of clinically apparent disease, sporadically seen in the study area. The effect of a monthly tsetse-borne trypanosomiasis-focused control programme (based on the application 0.005% deltamethrin spray formulation, applied only to the lower quarters of cattle) on the kinetics of bovine TBIs was assessed at the village level. Longitudinal monitoring of control and treated cattle was conducted over the period of eleven months. Results generated provide input to the improvement of future control strategies to be rolled out across SSA, aiming to achieve an integrated control of both trypanosomiasis and TBIs. The present thesis contributes to a better understanding of the epidemiology of bovine TBIs in Nigeria as well as in the rest of West Africa, using a highly sensitive tool of wide applicability. These findings will be shared with the local pastoralist communities to further promote effective yet sustainable, vector control, in tune with the traditional long-established practices.

Made available in DSpace on 2016-08-11T14:41:26Z (GMT). No. of bitstreams: 1 LuanaFS_DISSERT (1).pdf: 878379 bytes, checksum: 33da82b9ffe4df27a055e3cb7283f62a (MD5) Previous issue date: 2014-03-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Chagas disease affects humans and many animals susceptible, among which dogs are considered the main reservoir in the domestic cycle, and the diagnosis in this important species for assessing the risk of transmission to the population in a region. The successful control and prevention requires knowledge among the population about the disease and ways to avoid it. In this context, we observe the Community Health Agents (CHA), working in the dissemination of information on these and other endemic diseases. Thus, the present study aimed to evaluate the knowledge about Chagas disease by owners of dogs positive for the disease and, in addition, verify that the CHA active in the neighborhoods where these owners reside, know Chagas disease to perform a job education in satisfactory health, and to assess whether these agents include the prevention of disease in their daily work and municipal management empowers and provides working conditions for these professionals. Several interviews with 34 owners of dogs seropositive for Chagas disease and 48 were performed with CHA. In both cases was used a semi-structured questionnaire with open and closed questions about Chagas disease, and for CHA, were added questions about the prevention and control activities performed by them and about the conditions of work offered for these professionals. In addition, at the time of the visit to interview the owners, blood was collected from seropositive dogs to confirm the diagnosis by Polymerase Chain Reaction (PCR). Of the 34 dogs, nine (26.47%) had a diagnosis confirmed by PCR, confirming the presence of the parasite in the peripheral circulation of the animal and maintaining the consequent risk of the disease cycle. There was also a lack of knowledge of the owners about the symptoms of human Chagas disease, vector characteristics, general preventive measures of the disease susceptibility of dogs, symptoms, cure and vaccine canine Chagas disease, and the habit of accumulating matter organic outside the home, which acts as a risk factor for the occurrence of the disease in animals and men who share the same environment. However, there was no association between this environmental risk factor or between people's knowledge about the disease and positivity of dogs. About the CHA, it was found that although these show know the susceptibility of humans to the disease, its symptoms, the vector and measures to prevent it, they do not know the etiologic agent, the mechanisms of transmission and prevention of the same.It was also found that there is little inclusion of health education activities related to the Chagas disease in their daily work and conditions offered by the municipality are unsatisfactory. Thus, the research highlights the importance of establishing monitoring programs for Chagas infection in domestic animals and from this, health services can identify areas at risk of transmission, and encourage education work in more emphatic by the CHA health in these areas. As a consequence, the population at risk know more about the disease and ways to prevent it, and thus there will be more successful in the prevention and control the disease / A doença de Chagas acomete o homem e diversos animais suscetíveis, dentre os quais os cães são considerados os principais reservatórios no ciclo doméstico, sendo o diagnóstico nessa espécie importante para avaliação do risco de transmissão para população em uma região. O êxito no controle e prevenção da doença requer o conhecimento por parte da população sobre a enfermidade e as formas de evitá-la. Nesse contexto, observam-se os Agentes Comunitários de Saúde (ACS), atuando na divulgação de informações sobre essa e outras endemias. Assim, o presente estudo objetivou avaliar o conhecimento sobre a doença de Chagas por proprietários de cães sororreagentes a antígenos de T. cruzi e, paralelamente, verificar se os ACS atuantes nos bairros em que esses proprietários residem, conhecem a doença de Chagas para realizar um trabalho de educação em saúde satisfatório, bem como avaliar se esses agentes incluem a prevenção da doença em seu trabalho diário e se a gestão municipal capacita e fornece condições de trabalho para esses profissionais. Para tanto, foram realizadas entrevistas com 34 proprietários de cães sororreagentes 48 ACS com área de atuação nos bairros de residência desses proprietários. Utilizou-se nos dois casos, questionário semiestruturado contendo perguntas sobre a doença, sendo que para os ACS, acrescentaram-se questões sobre as atividades de prevenção e controle realizadas por eles e sobre suas condições de trabalho. Em adição, no momento da visita para entrevista dos proprietários, foi coletado sangue dos cães sororreagentes para confirmação do diagnóstico por Reação em Cadeia da Polimerase (PCR). Dos 34 cães, nove (26,47%) tiveram resultados positivos na PCR, confirmando a presença do parasita na circulação periférica do animal, e consequente risco de manutenção do ciclo da doença. Verificou-se ainda falta de conhecimento dos proprietários acerca dos sintomas da doença de Chagas humana, características do vetor, medidas gerais de prevenção da doença, suscetibilidade dos cães, sintomas, inexistência de cura e vacina para a doença canina, além do hábito de acumular matéria orgânica no peridomicílio, que atua como fator de risco para a ocorrência da doença nos animais e homens que compartilham do mesmo ambiente. No entanto, não houve associação entre este fator de risco ambiental ou entre o conhecimento da população sobre a doença e a positividade dos cães. Sobre os ACS, constatou-se que, embora estes demonstrem conhecer a suscetibilidade do homem à doença, seus sintomas, o vetor e medidas para evitá-lo, eles desconhecem o agente etiológico, os mecanismos de prevenção e de transmissão da mesma. Verificou-se ainda que a inclusão de atividades de educação em saúde relacionadas à doença no seu trabalho diário é insuficiente e as condições oferecidas pelo município são insatisfatórias. Dessa forma, a pesquisa destaca a importância da criação de programas de monitoramento da infecção chagásica nos animais domésticos e a partir disso, a possibilidade de identificação pelos serviços de saúde das áreas com risco de transmissão, além de incentivar um trabalho de educação em saúde mais enfático pelos ACS nestas áreas. Como consequência, haverá maior êxito na prevenção e controle dessa importante antropozoonose

Trypanosoma evansi is a protozoan parasite which infects a wide variety of mammalian hosts leading to the development of trypanosomiasis. Several papers have investigated the enzymatic changes in lymphocytes, important cells involved in immune responses, which are important for understanding the pathological mechanism of trypanosomiasis in animals. Among them we highlight the ectoATPases, enzymes that hydrolyze extracellular nucleotides and nucleosides of adenine. The curcumin (cur) has been associated with several beneficial effects associated with its use in animals experimentally infected with T. evansi, since this compound exhibits its properties among inflammatory and anti-parasitic effects. This study aimed to evaluate the activity of enzymes of the purinergic system in lymphocytes of rats supplemented or not with curcumin 30 days before infection with Trypanosoma evansi. Thirty-two adult male Wistar rats were divided into four groups. The uninfected control group (C) received saline intraperitoneally (IP), the infected control group (CI) received by the same route 0.2 ml of blood with 1x106 parasites and treatment with corn oil. The group pre-infection 20 (PreI20) received 20mg/kg curcumin and pre-infection group 60 (PreI60) received 60mg/kg of curcumin for 30 days prior to inoculation with T. evansi. After inoculation, the 03 treated groups continued to receive daily curcumin within 15 days before euthanasia. The NTPDase activity for both the hydrolysis of ATP to ADP increased significantly in the infected control group compared to the control group (P <0.05). The ADA activity decreased significantly in the infected control group compared to the control (P <.05). The use of curcumin at doses of 20 and 60 mg / kg for 30 days prior to infection with T.evansi reduced significantly NTPDase activity and increased significantly ADA activity in the treated groups (P <0.05). The results of this study support the evidence that the use of curcumin prior infection with T. evansi induces immunomodulatory effects, since they maintain the NTPDase activity reduced in lymphocytes, and maintains high ADA activity, favoring the response against the parasite. Thus, it is suggested that curcumin can be used as a food supplement for animals in areas where trypanosomosis is endemic. / O Trypanosoma evansi é um protozoário o qual infecta uma grande diversidade de hospedeiros mamíferos levando ao desenvolvimento da tripanossomíase. Diversos trabalhos têm investigado as alterações enzimáticas em linfócitos, importantes células envolvidas com respostas imunológicas, as quais são importantes para a compreensão do mecanismo patológico da tripanossomíase em animais. Dentre elas se destacam as NTPDases, enzimas que hidrolisam nucleotídeos e nucleosídeos extracelulares de adenina. A curcumina (Cur) tem sido relacionada com diversos efeitos benéficos associados ao seu uso em animais experimentalmente infectados com o T. evansi, uma vez que este composto apresenta dentre suas propriedades efeitos antiinflamatórios e antiparasitários. Este estudo teve por objetivo avaliar a atividade das enzimas do sistema purinérgico nos linfócitos de ratos, suplementados ou não com curcumina 30 dias antes da infecção por Trypanosoma evansi. Trinta e dois ratos Wistar adultos foram distribuídos em grupos controle não infectado (C), recebeu solução fisiológica via intraperitoneal (IP), o grupo controle infectado (CI) recebeu pela mesma via 0,2ml de sangue com 1x106 parasitas e tratamento com óleo de milho. O grupo pré-infecção 20 (PreI20) recebeu 20mg/kg de curcumina e o grupo pré-infecção 60 (PreI60) recebeu 60mg/kg de curcumina por 30 dias prévios à inoculação com T. evansi.. Após a inoculação, os 3 grupos tratados continuaram a receber a curcumina diariamente no período de 15 dias até a eutanásia. A atividade da NTPDase tanto para a hidrólise do ATP quanto do ADP aumentou significativamente no grupo CI quando comparado ao grupo controle (P<0,05). A atividade da ADA diminuiu significativamente no grupo CI em relação ao controle (P<0,05). A utilização da Curcumina nas doses de 20 e 60mg/Kg por 30 dias prévios a infecção com o T. evansi reduziu significativamente a atividade da NTPDase e aumentou significativamente a atividade da ADA nos grupos tratados (P<0,05). Os resultados deste trabalho reforçam a evidencia que o uso da curcumina previamente a infecção por T. evansi induz efeitos imunomodulatórios, pois mantêm a atividade da NTPDase nos linfócitos reduzida, e mantém alta a atividade da ADA, favorecendo a resposta contra o parasita. Desta forma, sugere-se que a curcumina possa ser utilizada como suplemento alimentar para animais em áreas onde a tripanosomose é endêmica.

Made available in DSpace on 2014-06-11T19:27:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-08-18Bitstream added on 2014-06-13T20:16:26Z : No. of bitstreams: 1 viol_ma_me_araca.pdf: 293015 bytes, checksum: bdc10c5bc3d8d20c951f2fc3b6dc7f4e (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O objetivo deste estudo foi detectar reações cruzadas por Leishmania spp. e Trypanossoma cruzi pelo Ensaio Imunoenzimático Indireto (ELISA), pela Reação de Imunofluorescência Indireta (RIFI) e pela Reação em Cadeia da Polimerase (PCR). Assim, foram colhidas 408 amostras sanguíneas de cães domiciliados no município de Araçatuba,SP, de ambos os sexos, de diversas raças e com idade a partir de seis meses. Em relação à Leishmania spp., pela RIFI, 14,95 % (61/408) foram reagentes. A positividade por meio do ELISA, foi de 20,10% (82/408) e pela PCR, 29,66% (121/408), com diferença significativa para o sexo e a idade destes animais (p<0,05). Para Trypanosoma spp., a ocorrência de anticorpos pelo ELISA foi de 10,54% (43/408) e pela PCR, 2,45% (10/408) cães foram positivos. Pela RIFI, 10,29% (42/408) dos animais foram considerados positivos e somente o sexo apresentou diferença significativa (p<0,05). Neste trabalho, constatou-se que 10,54%(43/408) dos animais foram soropositivos por ELISA para Trypanosoma spp., sendo que 79,07%(34/43) obtiveram resultados positivos no diagnóstico molecular para Leishmania spp. e dos 10,29% (42/408) positivos por RIFI, 95,24% (40/42) dos cães confirmaram a infecção por este parasita. Por meio dos resultados obtidos, pode-se inferir que foram evidenciadas reações cruzadas nos ensaios sorológicos para ambos os protozoários, nos animais analisados neste trabalho / The aim of this study was to detect cross-infection by Leishmania spp. and Trypanosoma spp. by indirect immunosorbent assay (ELISA), by Indirect Immunofluorescence (IFA) and by the Polymerase Chain Reaction (PCR). Thus, blood samples were collected from 408 domestic dogs of both sexes, different races and ages from six months. For Leishmania spp. by IFA, 14.95% (61/408) were positive. Positive by ELISA, was 20.10% (82/408), and PCR 29.66% (121/408), with significant difference for sex and age of animals (p <0.05). For Trypanosoma spp., the occurrence of antibodies by ELISA, was 10.54% (43/408), and PCR, 2.45% (10/408) dogs were positive. By IFA, 10.29% (42/408) of the animals were considered positive and only sex was significant difference (p <0.05). In this work it was found that 10.54% (43/408) animals were seropositive by ELISA for Trypanosoma spp., 79.07% (34/43) had positive results in molecular diagnostic for Leishmania spp. and 10.29% (42/408) positive by IFA, 95.24% (40/42) dogs confirmed the infection by this parasite. Through the results obtained can be inferred that cross-infection were observed by both protozoa in animals of this paper

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Trypanosoma evansi is the causative agent of the disease known as Mal das cadeiras or Surra in horses. Has a wide geographical distribution and is commonly found parasitizing several species of domestic and wild animals. Anemia is a common feature and perhaps the most important in infections with T. evansi, however, the mechanisms by which it originates has not been fully elucidated. Considering that iron deficiency may play a crucial role in anemia caused by trypanosomiasis, due to their involvement in hematopoietic, the aim of this study was to evaluate the possible effects of experimental infection with Trypanosoma evansi in Wistar rats on the iron status and of its forms of storage and carting, and also storage in the bone marrow level, establishing a correlation with hematologic findings. To that end, 32 male Wistar rats were divided into four groups, two control groups (C5 and C30) composed by six non-inoculated animals and two test groups (T5 and T30) inoculated with T. evansi, with 10 animals in each group. Blood samples were collected at 5 days post-inoculation (C5 and T5) and 30 days post-inoculation (C30 and T30). Iron status was determined in serum using commercial kits of ferrozine and cromazurol iron, ferritin, transferrin and iron binding capacity. The transferrin saturation index was calculated from the results obtained. The bone marrow was also evaluated for the presence of iron, by the reaction of Pearls. It was observed that the levels of iron, cromazurol iron and total and latent iron binding capacity decreased significantly (P <0.05) at 5 and 30 days pi in animals in the infected group when compared to the control group. Since the levels of transferrin and ferritin increased (P <0.05). The transferrin saturation index increased to 5 days pi, observing the decline of the index at 30 days pi. Infected animals showed a greater tendency to accumulate iron in bone marrow. Infection with T. evansi in rats caused anemia and changes in iron metabolism, as those related to the peaks of parasitemia. These results suggest that changes in iron metabolism may be related to body's immune response to infection and anemic status of infected animals. / O Trypanosoma evansi é o agente etiológico da doença conhecida como Mal das Cadeiras ou Surra em equinos. Apresenta ampla distribuição geográfica e é comumente observado parasitando diversas espécies de animais domésticos e silvestres. A anemia é uma característica comum e talvez a mais importante nas infecções por T. evansi, porém, os mecanismos pelos quais ela se origina ainda não foram completamente elucidados. Considerando-se que deficiência de ferro pode desempenhar um papel crucial na anemia causada pela tripanossomose, devido ao seu envolvimento nos processos hematopoiéticos, o objetivo deste estudo foi avaliar os possíveis efeitos da infecção experimental por Trypanosoma evansi em ratos Wistar sobre o status do ferro e de suas formas de armazenagem e carreamento e, ainda, estocagem em nível de medula óssea, estabelecendo uma correlação com os achados hematológicos. Para isso foram utilizados 32 ratos machos da linhagem Wistar, distribuídos em quatro grupos, sendo dois grupos controle (C5 e C30) compostos de seis animais não inoculados em cada grupo e dois grupos teste (T5 e T30), inoculados com T. evansi, com 10 animais em cada grupo. Amostras de sangue foram coletadas no dia 5 pós-inoculação (C5 e T5) e dia 30 pós-inoculação (C30 e T30). O status do ferro foi determinado em soro, utilizando-se kits comerciais de ferro cromazurol e ferrozine, ferritina, transferrina e capacidade de ligação do ferro. Os índices de saturação da transferrina foram calculados a partir dos resultados obtidos. A medula óssea também foi avaliada, quanto à presença de ferro, através da reação de Pearls. Foi observado que os níveis de ferro, ferro cromazurol e capacidade total e latente de fixação do ferro diminuíram significativamente (P<0,05) aos 5 e 30 dias pi nos animais infectados em relação ao grupo controle. Já os níveis de transferrina e ferritina aumentaram (P<0,05). O índice de saturação da transferrina aumentou aos 5 dias pi, observando-se declínio do índice aos 30 dias pi. Os animais infectados apresentaram tendência a um maior acúmulo de ferro na medula óssea. A infecção por T. evansi em ratos causou anemia e alterações no metabolismo do ferro, estando estas relacionadas aos picos de parasitemia. Estes resultados sugerem que as alterações no metabolismo do ferro podem estar relacionadas à resposta imune do organismo à infecção e ao estado anêmico dos animais parasitados.

Made available in DSpace on 2014-10-09T12:35:47Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:51Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP