Made available in DSpace on 2014-06-11T19:27:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-11Bitstream added on 2014-06-13T20:36:41Z : No. of bitstreams: 1 sacchi_abv_me_jabo.pdf: 876901 bytes, checksum: bbd58ecdb2c29112b3d0b1112c51b549 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O presente trabalho teve por objetivo pesquisar no sangue de cervos-do-pantanal (B. dichotomus), a presença de DNA de agentes rickettsiais, tais como Ehrlichia chaffeensis, E. ewingiii, E. canis, Anaplasma phagocytophilum, A. marginale e Neorickettsia risticii, pela Reação em Cadeia pela Polimerase (PCR), além de estudar a prevalência de anticorpos anti-E. chaffeensis e anti-A. phagocytophilum utilizando-se a Reação de Imunofluorescência Indireta (RIFI). Os 143 animais utilizados foram capturados durante o desenvolvimento do Projeto Cervo-do-Pantanal (1998 a 2002) na área de inundação da Usina Hidrelétrica de Porto Primavera, no Rio Paraná, e divididos em quatro sub-populações de acordo com o local e momento da captura, em áreas denominadas MS01, MS02 (Mato Grosso do Sul, antes e após a inundação, respectivamente), PX (Rio do Peixe, depois da primeira cota de inundação) e AGUA (Rio Aguapeí, depois da inundação). Na avaliação sorológica, as freqüências de animais positivos para anticorpos anti-E. chaffeensis e anti-A. phagocytophilum foram de 76,76% e 20,20% em MS01, 88,88% e 22,22% em PX, 88,88% e 5,55% em MS02, e 94,12% e 5,88% em AGUA, respectivamente. Na pesquisa de DNA, dos 143 animais testados, 61 (42,65%) foram positivos para E. chaffeensis, sendo 38 (38,38%) de MS01, 4 (44,44%) de PX, 12 de MS02 (66,66%) e 7 (41,18%) de AGUA. Amostras positivas enviadas para seqüenciamento revelaram 100% de similaridade com amostras de Ehrlichia chaffeensis da Argentina e dos Estados Unidos (números de acesso no Genbank EU826516.2 e AF416764.1, respectivamente). Já para o genogrupo de A. phagocytophilum, 70 cervos (48,95%) foram considerados positivos. Destes, 51 (51,51%) são provenientes de MS01, 12 (66,66%) de MS02 e 7 (41,18%) de AGUA. Animais provenientes de PX foram todos negativos. Amostras positivas enviadas para seqüenciamento... / The present work had as objective to research in the blood of marsh deer (B. dichotomus), the presence of rickettsial agents DNA such as Ehrlichia chaffeensis, E. ewingii, E. canis, Anaplasma phagocytophilum, A. marginale e Neorickettsia risticii, by the Polimerase Chain Reaction (PCR), as well as studying the prevalence of anti-E. chaffeensis and anti-A. phagocytophilum antibodies using Indirect Imunofluorescence Reaction (IFA). The 143 animals that were used were captured during the development of the Marsh Deer Project (1998 to 2002) in the flood area of the Porto Primavera Hydroelectric Power Station, in Parana River, and divided in four sub-populations according to the local and moment of the capture, in areas denominated MS01, MS02 (Mato Grosso do Sul, before and after flood respectively), PX (Peixe’s River, after the first flood quota) and AGUA (Aguapeí River, after flood). In the serological avaliation, the frequency of positive animals for anti-E. chaffeensis and anti-A. phagocytophilum antibodies were 76,76% and 20,20% in MS01, 88,88% and 22,22% in PX, 88,88% and 5,55% in MS02, and 94,12% and 5,88% in AGUA, respectively. In the DNA research, from the 143 tested animals, 61 (42,65%) were positive for E. chaffeensis, 38 (38,38%) from MS01, 4 (44,44%) from PX, 12 from MS02 (66,66% and 7 (41,18%) from AGUA. Positive samples send to sequency demonstrate 100% of similarity with samples of Ehrlichia chaffeensis from Argentina and United States (numbers of access in Genbank EU826516.2 and AF416764.1, respectively). For the A. phagocytophilum genogroup, 70 deers (48,95%) were considered positive. Of these, 51 (51,51%) come from MS01, 12 (66,66%) from MS02 and 7 (41,18%) from AGUA. The animals that come from PX were all negative. Positive samples send to sequencing demonstrated 99% of similarity with a sample of Anaplasma... (Complete abstract click electronic access below)

Orientador: Rosangela Zacarias Machado / Banca: José Maurício Barbanti Duarte / Banca: Natalino Hajime Yoshinari / Resumo: O presente trabalho teve por objetivo pesquisar no sangue de cervos-do-pantanal (B. dichotomus), a presença de DNA de agentes rickettsiais, tais como Ehrlichia chaffeensis, E. ewingiii, E. canis, Anaplasma phagocytophilum, A. marginale e Neorickettsia risticii, pela Reação em Cadeia pela Polimerase (PCR), além de estudar a prevalência de anticorpos anti-E. chaffeensis e anti-A. phagocytophilum utilizando-se a Reação de Imunofluorescência Indireta (RIFI). Os 143 animais utilizados foram capturados durante o desenvolvimento do Projeto Cervo-do-Pantanal (1998 a 2002) na área de inundação da Usina Hidrelétrica de Porto Primavera, no Rio Paraná, e divididos em quatro sub-populações de acordo com o local e momento da captura, em áreas denominadas MS01, MS02 (Mato Grosso do Sul, antes e após a inundação, respectivamente), PX (Rio do Peixe, depois da primeira cota de inundação) e AGUA (Rio Aguapeí, depois da inundação). Na avaliação sorológica, as freqüências de animais positivos para anticorpos anti-E. chaffeensis e anti-A. phagocytophilum foram de 76,76% e 20,20% em MS01, 88,88% e 22,22% em PX, 88,88% e 5,55% em MS02, e 94,12% e 5,88% em AGUA, respectivamente. Na pesquisa de DNA, dos 143 animais testados, 61 (42,65%) foram positivos para E. chaffeensis, sendo 38 (38,38%) de MS01, 4 (44,44%) de PX, 12 de MS02 (66,66%) e 7 (41,18%) de AGUA. Amostras positivas enviadas para seqüenciamento revelaram 100% de similaridade com amostras de Ehrlichia chaffeensis da Argentina e dos Estados Unidos (números de acesso no Genbank EU826516.2 e AF416764.1, respectivamente). Já para o genogrupo de A. phagocytophilum, 70 cervos (48,95%) foram considerados positivos. Destes, 51 (51,51%) são provenientes de MS01, 12 (66,66%) de MS02 e 7 (41,18%) de AGUA. Animais provenientes de PX foram todos negativos. Amostras positivas enviadas para seqüenciamento... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The present work had as objective to research in the blood of marsh deer (B. dichotomus), the presence of rickettsial agents DNA such as Ehrlichia chaffeensis, E. ewingii, E. canis, Anaplasma phagocytophilum, A. marginale e Neorickettsia risticii, by the Polimerase Chain Reaction (PCR), as well as studying the prevalence of anti-E. chaffeensis and anti-A. phagocytophilum antibodies using Indirect Imunofluorescence Reaction (IFA). The 143 animals that were used were captured during the development of the Marsh Deer Project (1998 to 2002) in the flood area of the Porto Primavera Hydroelectric Power Station, in Parana River, and divided in four sub-populations according to the local and moment of the capture, in areas denominated MS01, MS02 (Mato Grosso do Sul, before and after flood respectively), PX (Peixe's River, after the first flood quota) and AGUA (Aguapeí River, after flood). In the serological avaliation, the frequency of positive animals for anti-E. chaffeensis and anti-A. phagocytophilum antibodies were 76,76% and 20,20% in MS01, 88,88% and 22,22% in PX, 88,88% and 5,55% in MS02, and 94,12% and 5,88% in AGUA, respectively. In the DNA research, from the 143 tested animals, 61 (42,65%) were positive for E. chaffeensis, 38 (38,38%) from MS01, 4 (44,44%) from PX, 12 from MS02 (66,66% and 7 (41,18%) from AGUA. Positive samples send to sequency demonstrate 100% of similarity with samples of Ehrlichia chaffeensis from Argentina and United States (numbers of access in Genbank EU826516.2 and AF416764.1, respectively). For the A. phagocytophilum genogroup, 70 deers (48,95%) were considered positive. Of these, 51 (51,51%) come from MS01, 12 (66,66%) from MS02 and 7 (41,18%) from AGUA. The animals that come from PX were all negative. Positive samples send to sequencing demonstrated 99% of similarity with a sample of Anaplasma... (Complete abstract click electronic access below) / Mestre

Anaplasmosis, a persistent intraerythrocytic infection of cattle by Anaplasma marginale, causes severe anemia and a higher rate of abortion, resulting in significant loss to both dairy and beef industries. Clinical diagnosis is based on symptoms and confirmatory laboratory tests are required. Currently, all the diagnostic assays have been developed with whole antigens with indirect ELISA based on multiple epitopes. In a pioneer investigation we demonstrated the use of critical motifs of an epitope as biomarkers for immunosensor applications. Mimotopes of the MSP1a protein functional epitope were obtained through Phage Display after three cycles of selection of a 12-mer random peptide library against the neutralizing monoclonal antibody 15D2. Thirty-nine clones were randomly selected, sequenced, translated and aligned with the native sequence. The consensus sequences SxSSQSEASTSSQLGA was obtained, which is located in C-terminal end of the 28-aa repetitive motif of the MSP1a protein, but the alignment and sequences variation among mimotopes allowed us to map the critical motif STSSxL within the consensus sequence. Based on these results, two peptides were chemically synthesized; one based on the critical motif (STSSQL, Am1) and the other based on the consensus sequence aligned with the native epitope (SEASTSSQLGA, Am2). Sera from 24 infected and 52 healthy animals were tested by ELISA for reactivity against Am1 and Am2, which presented sensitivities of 96% and 100%, respectively. The Am1 peptide was incorporated onto a biolectrode (graphite modified with poly-3-hydroxyphenylacetic acid) and direct serum detection was demonstrated by impedance, differential pulse voltammetry, and atomic force microscopy. The electrochemical sensor system proved to be highly effective in discriminating sera from positive and negative animals. These immunosensors were highly sensitive and selective for positive IgG, contaminants did not affect measurements, and were based on a simple, fast and reproducible electrochemical system. / Anaplasmose, uma infecção intraeritrocitária obrigatória de bovinos, causada pela Anaplasma marginale, causa severa anemia e alta taxa de aborto, resultando em perda significativa para a indústria de laticínios e carne. O diagnóstico clínico é baseado nos sintomas e exames laboratorias confirmatórios são necessários. Atualmente, todos os ensaios de diagnósticos têm sido desenvolvidos com ELISA indireto de antígenos totais baseado em epítopos múltiplos. Em uma investigação pioneira demonstramos o uso de motivos críticos de um epítopo como biomarcador para a aplicação em imunossensores. Mimotopos do epítopo funcional da proteína MSP1a foram obtidos por meio de Phage Display, após três ciclos de seleção, de uma biblioteca randômica de peptídeos 12-mer contra o anticorpo monoclonal 15D2. Trinta e nove clones foram selecionados aleatoriamente, sequenciados, traduzidos e alinhados com a sequência nativa. Foi obtida a sequência consenso SxSSQSEASTSSQLGA, que está localizada na extremidade C-terminal do motivo repetitivo de 28-aa da proteína MSP1a, mas o alinhamento e a variação das sequências entre os mimotopos nos permitiu mapear o motivo crítico STSSxL dentro da sequência consenso. Com base nesses resultados, dois peptídeos foram quimicamente sintetizados; um baseado no motivo crítico (STSSQL, Am1) e o outro baseado na sequência consenso alinhada com o epítopo nativo (SEASTSSQLGA, Am2). Soro de 24 animais infectados e 52 animais saudáveis foram testados por ELISA quanto à reatividade contra Am1 e Am2, que apresentou sensibilidades de 96% e 100%, respectivamente. O peptide Am1 foi incorporado a um bioeletrodo (grafite modificado com ácido poli-3-hidroxyfenilacético) e a detecção direta de soro foi demonstrada por impedância, voltametria de pulso diferencial e microscopia de força atômica. O sistema de sensor eletroquímico provou ser altamente eficaz em soro de animais positivos de negativos. Este imunossensor foi altamente sensível e seletivo para IgG positiva, contaminantes não afetaram as medições, e foram baseados e um sistema simples, rápido e reprodutível. / Doutor em Genética e Bioquímica

No description available.

Master of Science / Department of Diagnostic Medicine/Pathobiology / Roman Reddy R. Ganta / Ehrlichia and Anaplasma species are rickettsial organisms which infect a variety of mammalian species. The organisms are transmitted from ticks and are maintained in reservoir hosts. Several pathogens have been identified in recent years as the causative agents for emerging infections in people. One of the primary reservoir hosts for the pathogens is the white tailed deer. In this study, 147 deer blood samples and 37 ticks were evaluated for the prevalence of Ehrlichia/Anaplasma species by TaqMan-based real time amplification assay and DNA sequence analysis. One hundred and thirteen (74%) samples tested positive with the Ehrlichia/Anaplasma genera-specific probe. Further analysis of the samples with the probes specific for human ehrlichiosis agents, E. chaffeensis and E. ewingii identified 4 (2.7%) and 7 (4.7%) positives, respectively. Test positives from 24 randomly selected samples were further evaluated by sequence analysis targeting to a 450 bp segment of 16S rRNA gene. All 24 samples were confirmed as positive for the Ehrlichia GA isolate # 4 (GenBank #U27104.1). DNAs from 37 pools of ticks collected from the white tailed deer were also evaluated. The TaqMan-based real time PCR assay with Anaplasma/Ehrlichia common probe identified 29 (78%) tick pools as positives whereas E. chaffeensis- and E. ewingii-specific probes identified three (8%) and one (3%) positives, respectively. The PCR and sequence analysis of tick samples identified Gram-negative bacteria species which included one endosymbiont of Rickettsia species (one tick pool), one Alcaligenes faecalis strain (three tick pools), five different Pseudomonas species (9 tick pools) and five different uncultured bacteria organisms (7 tick pools). Although the pathogenic potential of the white-tailed deer isolates of Anaplasma and Ehrlichia agents remains to be established, their high prevalence and the presence of human ehrlichiosis pathogens in white-tailed deer is similar to earlier findings. The high prevalence of the deer isolates of Anaplasma and Ehrlichia species demonstrates the need for further assessment of the pathogenic potential of these organisms to people and domestic animals.

The present thesis examines questions related to the temporal origin of the Flavivirus genus and the ecology of tick-borne pathogens. In the first study, we date the origin and divergence time of the Flavivirus genus. It has been argued that the first flaviviruses originated after the last glacial maximum. This has been contradicted by recent analyses estimating that the tick-borne flaviviruses emerged at least before 16,000 years ago. It has also been argued that the Powassan virus was introduced into North America at the time between the opening and splitting of the Beringian land bridge. Supported by tip date and biogeographical calibration, our results suggest that this genus originated circa 120,000 (156,100–322,700) years ago if the Tamana bat virus is included in the genus, or circa 85,000 (63,700–109,600) years ago excluding the Tamana bat virus. In the second study we estimate the prevalence of tick-borne encephalitis virus (TBEV) in host-seeking Ixodes ricinus from 29 localities in Sweden and compare our data with those of neighbouring countries. Nymphs and adult ticks were screened for TBEV using a real-time PCR assay. The mean TBEV prevalence for all tick stages combined was 0.26% for Sweden and 0.28% for all Scandinavian countries, excluding Iceland. The low prevalence of TBEV in nature may partly be explained by the fact that TBEV occurs in spatially small foci and that the inclusion of ticks from non-infected foci will reduce the prevalence estimate. In the third and fourth study, we conducted the first large-scale investigations to estimate the prevalence and geographical distribution of Anaplasma spp. and Rickettsia spp. in host-seeking larvae, nymphs and adults of I. ricinus ticks in Sweden. Ticks were collected from several localities in central and southern Sweden and were subsequently screened for the presence of Anaplasma spp. and Rickettsia spp. using a real-time PCR assay. For all active tick stages combined, the mean prevalence of Anaplasma spp. and Rickettsia spp. in I. ricinus in Sweden was estimated to 1.1% and 4.8%, respectively. It was also shown that A. phagocytophilum and R. helvetica are the main Anaplasma and Rickettsia species occurring in Sweden.

Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-10-19T13:49:16Z No. of bitstreams: 1 2016 - Claudia Bezerra da Silva.pdf: 8032175 bytes, checksum: ef71dd2a0e7801e9000e116c822a3a00 (MD5) / Made available in DSpace on 2017-10-19T13:49:16Z (GMT). No. of bitstreams: 1 2016 - Claudia Bezerra da Silva.pdf: 8032175 bytes, checksum: ef71dd2a0e7801e9000e116c822a3a00 (MD5) Previous issue date: 2016-03-11 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / and investigate the circulation of this agent in dogs in the Itaguai microregion, Rio de Janeiro, Brazil, and dogs and ticks in two provinces of the island of Cuba, analyzing epidemiological aspects associated with infections caused by this bacterium in dogs. A new real-time polymerase chain reaction method (qPCR) was patterned to target the citrate synthase gene (gltA) for the identification of A. platys in naturally infected dogs. The primers and probe were designed to amplify a fragment of 84 base pairs based on gltA gene sequences of A. platys available in GenBank. 186 blood samples of dogs from Itaguai microregion, Rio de Janeiro, Brazil, were tested by qPCR. The same samples were tested by cytology and nested polymerase chain reaction (nPCR, 16S rDNA) to determine the performance of qPCR front of these techniques. 17.20% of the samples tested positive by qPCR were significantly more than that detected by nPCR (13.98%). The qPCR technique was more specific than cytology, due to false-positive results obtained by optical microscopy. The prevalence of A. platys in dogs from Itaguai microregion was 14.4%. Dogs less than six months, infested by ticks, that spend the most of the time restrict to domestic environment and without shelter are factors associated with infection by this hemoparasite in dogs in the study area. During research, A. platys held in Cuba, 100 blood samples were collected from residents dogs in four cities located in the provinces of Havana and Mayabeque. When inspecting the animals, found ticks were collected, identified and carefully grouped, forming a total of 49 pools. DNA extracted from blood samples from dogs and ticks were subjected nPCR (16S rDNA). Positive samples in nPCR were also subjected to conventional PCR (gltA gene), and the products were sequenced. Only the species Rhipicephalus sanguineus sensu lato was found in Cuban dogs and 10.2% (n=5/49) of these ticks added to 16.0% (n=16/100) dogs were considered positive for A. platys. All sequences analyzed of the gltA and 16S rDNA genes, respectively, showed a 99-100% identity with sequences from A. platys reported in other countries. Phylogenetic analysis showed two clusters defined for the 16S rDNA gene and three clusters defined for the gltA gene. Based on the gltA gene, the deduced amino acid sequence showed two points of non-synonymous mutations at positions 88 and 168 compared to the reference sequence DQ525687. A preliminary study on the epidemiological aspects associated with infection with A. platys showed no statistical association with the variables studied (p> 0.05). This study also to report the first evidence of A. platys in both dogs and ticks in Cuba also presents for the first time the development of a new qPCR method that contributes to the advancement of research involving A. platys. The epidemiological study in Brazil allowed us to identify significant factors in the occurrence of canine anaplasmosis, while in Cuba, it can be concluded that more research is needed to assess what the deciding factors in the transmission and spread of A. platys in that country. / platys, e investigar a circula??o deste agente em c?es na microrregi?o de Itagua?, Rio de Janeiro, Brasil, e c?es e carrapatos em duas prov?ncias da ilha de Cuba, analisando aspectos epidemiol?gicos associados ? infec??o causada por esta bact?ria em c?es. Um novo m?todo de rea??o em cadeia da polimerase em tempo real (qPCR) foi padronizado com alvo no gene citrato sintase (gltA) para a identifica??o de A. platys em c?es naturalmente infectados. Os oligoiniciadores e a sonda foram desenhados para amplificar um fragmento de 84 pares de base baseado em sequ?ncias do gene gltA de A. platys dispon?veis no GenBank. 186 amostras de sangue de c?es da microrregi?o de Itagua?, Rio de Janeiro, Brasil, foram testados pela qPCR. As mesmas amostras foram testadas pela citologia e rea??o em cadeia da polimerase nested (nPCR, 16S rDNA) para determinar o desempenho da qPCR frente ? essas t?cnicas. 17,20% das amostras testadas pela qPCR foram positivas, significativamente mais do que detectado pela nPCR (13,98%). A t?cnica de qPCR foi mais espec?fica que a citologia, em virtude dos resultados falsopositivos obtidos pela microscopia ?ptica. A preval?ncia de A. platys em c?es da microrregi?o de Itagua? foi de 14,4%. C?es com menos de seis meses, infestados por carrapatos, que possam maior tempo restrito ao ambiente dom?stico e sem abrigo s?o fatores associados a infec??o por este hemoparasito em c?es na regi?o do estudo. Durante investiga??o de A. platys realizada em Cuba, 100 amostras de sangue foram coletadas de c?es residentes em quatro cidades localizadas nas prov?ncias de Habana e Mayabeque. Ao inspecionar os animais, carrapatos encontrados foram coletados, identificados e criteriosamente agrupados, formando um total de 49 pools. Amostras de DNA extra?das do sangue dos c?es e de carrapatos foram submetidas a nPCR (16S rDNA). Amostras positivas na nPCR foram tamb?m submetidas a PCR convencional (gene gltA), e os produtos foram sequenciados. Somente a esp?cie Rhipicephalus sanguineus sensu lato foi encontrada em c?es cubanos, e 10,2% (n=5/49) desses carrapatos somado aos 16,0% (n=16/100) de c?es foram considerados positivos para A. platys. Todas as sequ?ncias analisadas dos genes gltA e 16S rDNA, respectivamente, mostraram uma identidade de 99-100% com sequ?ncias de A. platys reportadas em outros pa?ses. A an?lise filogen?tica mostrou dois clusters definidos para o gene 16S rDNA e tr?s clusters definidos para o gene gltA. Com base no gene gltA, a sequ?ncia de amino?cidos deduzidos demonstrou dois pontos de muta??es n?o-sin?nimas nas posi??es 88 e 168 comparados com sequ?ncia de refer?ncia DQ525687. Um estudo preliminar sobre os aspectos epidemiol?gicos associados com a infec??o por A. platys demonstrou nenhuma associa??o estat?stica com as vari?veis avaliadas (p > 0,05). O presente estudo al?m de relatar a primeira evid?ncia de A. platys em ambos c?es e carrapatos em Cuba, tamb?m apresenta pela primeira vez o desenvolvimento de um novo m?todo de qPCR que contribui para o avan?o da pesquisa envolvendo A. platys. O estudo epidemiol?gico realizado no Brasil permitiu identificar fatores importantes na ocorr?ncia da anaplasmose canina, enquanto em Cuba, pode-se concluir que mais investiga??es s?o necess?rias para avaliar quais os fatores decisivos na transmiss?o e dispers?o de A. platys nesse pa?s.

Ticks and tick borne-diseases (TBD) are major challenges to cattle production among smallholder farmers in the semiarid areas of South Africa. Nguni cattle have been reported to be resistant to ticks and TBD, however, the mechanisms responsible for the trait are not fully understood. The broad objective of this study was to determine the mechanisms of resistance to ticks in Nguni cattle reared in the semiarid areas of South Africa. Tick infestation levels, body condition scores (BCS), packed cell volumes (PCV) and the molecular prevalence of A. marginale were determined in Nguni (n = 70) and local crossbred (n = 79) cattle reared in the semiarid areas of South Africa. Relationships among skin thickness, hair length, coat score and tick counts were assessed in seven to nine month old Nguni (n = 12) and Bonsmara (n = 12) heifers. As a follow up, cutaneous hypersensitivity responses to unfed larval extracts (ULE) of the ticks Rhipicephalus decoloratus and Rhipicephalus microplus were examined in heifers to determine host immunity to the ticks. Tick counts and inflammatory cell infiltrates in skin biopsies from feeding sites of adult R. microplus ticks in nine-month-old Nguni and Bonsmara heifers were also evaluated. The molecular prevalence of A. marginale was similar in the Nguni (47.7 %) and local crossbred (52.3 %) cattle. Nguni cattle suffered less severe losses from and were more vi resilient to A. marginale infection than local crossbreds. Nguni heifers had lower coat scores, hair length and tick counts than the Bonsmara heifers. The relationship between tick counts and coat score was positive and linear in the Nguni (y = 1.90x – 0.40) and quadratic in Bonsmara (y = -7.98x2 + 12.74x - 3.12) heifers. Bonsmara cattle showed a more intense immediate reaction and no delayed hypersensitivity reaction to ULE of Rhipicephalus ticks. Nguni heifers presented a less intense immediate reaction and a delayed hypersensitivity reaction at 72 h post inoculation with ULE of Rhipicephalus ticks. Reactions to R. decoloratus ULE produced a more intense skin response at all time intervals in both breeds than that of R. microplus. Parasitized sites in Nguni heifers had higher (P < 0.05) counts of basophils, mast and mononuclear cells than those in the Bonsmara heifers. Conversely, parasitized sites in Bonsmara heifers had higher (P < 0.05) neutrophil and eosinophil counts than those in the Nguni heifers. Tick count was negatively correlated (P < 0.05) with basophil and mast cell counts. There was a positive correlation between eosinophil counts and tick counts in both breeds, and between tick counts and mononuclear cell counts in the Bonsmara breed. It was concluded that smooth and short coats, delayed type hypersensitivity and cutaneous basophil and mast cell infiltrations are responsible for increased tick resistance in the indigenous Nguni cattle breed of South Africa. / Ph.D. University of KwaZulu-Natal, Pietermaritzburg 2013.

The main aim of the current study was to determine the prevalence and diversity of potentially zoonotic bacterial genera in accurately identified indigenous rodents from South Africa. Bacterial prevalence and diversity were determined by PCR amplification and sequence analyses. Rodents were molecularly identified by amplification and sequence analysis of the mitochondrial cytochrome b gene region. Three species (Aethomys ineptus, Mastomys coucha and Otomys angoniensis) belonging to murid species complexes were identified. Furthermore, phylogenetic analyses revealed that both the proposed subspecies (R. dilectus dilectus and R. d. chakae) within the recently erected Rhabdomys dilectus occur in Hammanskraal and at the University of Pretoria Experimental farm, both in the Gauteng Province of South Africa. An overall bacterial prevalence of 38.6 % was observed in kidney samples of commensal and natural indigenous rodents after molecular screening with broad range 16S rRNA gene primers. Nucleotide sequence analyses identified a diverse range of bacterial genera namely, Bartonella, Anaplasma, Helicobacter, Burkholderia, Streptococcus, Aerococcus and Lactobacillus. Some members of these genera have been identified as causative agents of human and animal diseases, being transmitted either through environmental contamination or through haematophagous arthropod vectors. Subsequent genus-specific bacterial screening focussed on vector-borne genera identified in the commensal and natural rodent populations sampled. Bartonella prevalence and genetic diversity was compared between a natural and commensal population of the southern multimammate mouse (M. coucha) using two gene regions (Citrate synthase gene and NADH dehydrogenase gamma subunit gene). A significantly higher infection prevalence was detected in the commensal population (92.9 %) as compared to the natural population (56.9 %). No differences however, were detected between infection status and the ectoparasite loads calculated for both rodent populations. Apart from several novel Bartonella strains identified in both M. coucha populations, phylogenetic analyses also identified a species of known zoonotic potential (B. elizabethae) in both populations. The present study represents one of the first to screen indigenous rodents for tick-borne members of the bacterial family Anaplasmataceae. Anaplasma bovis-like DNA was detected in five of the six rodent species sampled (A. ineptus, Lemniscomys rosalia, M. coucha, O. angoniensis and R. dilectus) at an overall prevalence of 39.2 %. The potentially zoonotic Ehrlichia ewingii was detected in M. coucha samples only at a prevalence of 5.3 %. The diverse bacterial genera detected in commensal and natural populations of indigenous rodents comprise members of zoonotic potential and agricultural significance, highlighting the importance of continuous disease surveillance of indigenous rodents. / Dissertation (MSc)--University of Pretoria, 2014. / National Research Foundation (NRF) / Zoology and Entomology / MSc / Unrestricted

No description available.