Single-strand conformation polymorphism was used to detect different haplotypes of the 16S mitochondrial rDNA gene within samples of Gulf Coast ticks, Amblyomma maculatum Koch, collected from Payne County, Oklahoma and Brazos and Refugio Counties, Texas. Ticks were collected from dogs, horses, and cattle. The haplotype frequencies from the cattle collections were compared to a similar study, conducted in 1999, to detect if any changes in frequencies had occurred. There were significant differences (p<0.05) between the haplotype frequencies from 1999 and 2007. The haplotype designated as D was highly prevalent in all sampled populations, however was not detected in Oklahoma and Texas eight years earlier. Possible explanations for this occurrence include ticks with this haplotype having a higher fecundity, resistance to drought, or resistance to acaricides. Comparisons of the haplotypes of ticks collected from cattle solely in 2007 showed that the haplotype frequencies of Brazos County and Payne County are more similar than to Refugio County. The haplotype frequencies found on various hosts were also compared and no significant differences were found (p>0.05).

Thesis (Ph.D.) -- University of Adelaide, Dept. of Zoology, 1980. / Typescript (photocopy).

Trabalhos recentes de genética, morfologia e biologia conduzidos nas Américas, demostraram que Amblyomma cajennense é um complexo de pelo menos seis espécies distintas, cada espécie associada a uma área biogeográfica. Neste contexto, o presente estudo conduzido no Brasil realizou análises morfológicas e moleculares de carrapatos adultos, previamente identificados como A. cajennense e depositados nas coleções de carrapatos Coleção Nacional de Carrapatos, da Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo, e na Coleção Acarológica do Instituto Butantan do Instituto Butantan de São Paulo. Amostras adicionais de carrapatos foram obtidos através de trabalhos de campo. Os carrapatos foram coletados em vida livre, animais domésticos (equinos, suínos) e silvestres atropelados (anta, tamanduá), durante três expedições de coleta, sendo uma no nordeste do país entre os municípios de Bequimão/MA e Estrela do Norte/GO; uma no noroeste do país entre os municípios de Presidente Médici/RO e Vila Bela da Santíssima Trindade/MT; e uma terceira no centro-norte do país entre os municípios de Sinop/MT e Cuiabá/MT. Os resultados morfológicos e moleculares obtidos demonstraram a ocorrência de pelo menos duas espécies distintas de carrapatos (A. cajennense sensu stricto e Amblyomma sculptum) do complexo A. cajennense ocorrendo no território nacional. De modo geral, a distribuição da espécie A. cajennense s. s. está confirmada no Brasil em três estados da região Norte (Pará, Rondônia e Tocantins), em um estado da região Nordeste (Maranhão) e do Centro-Oeste (Mato Grosso). Salienta-se um único encontro de uma fêmea de A. cajennense s. s. em uma propriedade rural do município de Porangatu, no extremo norte do estado de Goiás, na divisa com o estado de Tocantins. A ocorrência de A. sculptum está confirmada nos seguintes estados brasileiros da região Norte: Pará, Rondônia e Tocantins; Nordeste: Bahia, Maranhão, Pernambuco e Piauí; Centro-Oeste: Distrito Federal, Goiás, Mato Grosso e Mato Grosso do Sul; Sudeste: Espírito Santo, Minas Gerais, Rio de Janeiro e São Paulo; e Sul: Paraná. Estes dados indicam que o papel de cada uma destas espécies na transmissão de patógenos deve ser reavaliado de acordo com seu novo status taxonômico. / Recent genetic, biological and morphological studies have demonstrated that Amblyomma cajennense is a complex of at least six distinct species, each species linked to a biogeographic area in the American continent. In this context, the present study aimed to perform morphological and molecular analyzes of adult ticks, previously identified as A. cajennense, deposited in the collections of ticks \"Coleção Nacional de Carrapatos\", the Faculty of Veterinary Medicine and Zootechny of the University of São Paulo and in the \"Coleção Acarológica do Instituto Butantan\" the Butantan Institute of São Paulo. Adicional tick specimens were obtained through fieldwork. Ticks were collected in the vegetation, domestic animals (horses, pigs) and road-killed wild animals (tapir, anteater) during three field expeditions, one in the northeast of the country between the municipalities of Bequimão/MA and Estrela do Norte/GO; one in the northwest of the country between the municipalities of Presidente Médici/RO and Vila Bela da Santíssima Trindade/MT; and a third one in the center-north of the country between the municipalities of Sinop/MT and Cuiabá/MT. The morphological and molecular results demonstrated the occurrence of at least two distinct species of ticks (A. cajennense sensu stricto and Amblyomma sculptum) of the A. cajennense species complex occurring in the Brazilian land. In general, the distribution of the species A. cajennense s. s. is confirmed in Brazil in three northernern states (Pará, Rondônia and Tocantins) one Northeast state (Maranhão) and one Midwest state (Mato Grosso). It is note worthy the findings of a single female of A. cajennense s. s. on a farm in the municipality of Porangatu, in the far north of the state of Goiás at the northern end of the state of Goiás, at the border with the state of Tocantins. The occurrence of A. sculptum is confirmed in the following Brazilian states Northern region: Pará, Rondônia and Tocantins; Northeastern region: Bahia, Maranhão, Piauí and Pernambuco; Midwester region: Distrito Federal, Goiás, Mato Grosso and Mato Grosso do Sul; Southeastern region: Espírito Santo, Minas Gerais, Rio de Janeiro and São Paulo; and Southern region: Paraná. These data indicate that the role of each of these species in pathogen transmission should be re-assessed according to its new taxonomic status.

Trabalhos recentes de genética, morfologia e biologia conduzidos nas Américas, demostraram que Amblyomma cajennense é um complexo de pelo menos seis espécies distintas, cada espécie associada a uma área biogeográfica. Neste contexto, o presente estudo conduzido no Brasil realizou análises morfológicas e moleculares de carrapatos adultos, previamente identificados como A. cajennense e depositados nas coleções de carrapatos Coleção Nacional de Carrapatos, da Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo, e na Coleção Acarológica do Instituto Butantan do Instituto Butantan de São Paulo. Amostras adicionais de carrapatos foram obtidos através de trabalhos de campo. Os carrapatos foram coletados em vida livre, animais domésticos (equinos, suínos) e silvestres atropelados (anta, tamanduá), durante três expedições de coleta, sendo uma no nordeste do país entre os municípios de Bequimão/MA e Estrela do Norte/GO; uma no noroeste do país entre os municípios de Presidente Médici/RO e Vila Bela da Santíssima Trindade/MT; e uma terceira no centro-norte do país entre os municípios de Sinop/MT e Cuiabá/MT. Os resultados morfológicos e moleculares obtidos demonstraram a ocorrência de pelo menos duas espécies distintas de carrapatos (A. cajennense sensu stricto e Amblyomma sculptum) do complexo A. cajennense ocorrendo no território nacional. De modo geral, a distribuição da espécie A. cajennense s. s. está confirmada no Brasil em três estados da região Norte (Pará, Rondônia e Tocantins), em um estado da região Nordeste (Maranhão) e do Centro-Oeste (Mato Grosso). Salienta-se um único encontro de uma fêmea de A. cajennense s. s. em uma propriedade rural do município de Porangatu, no extremo norte do estado de Goiás, na divisa com o estado de Tocantins. A ocorrência de A. sculptum está confirmada nos seguintes estados brasileiros da região Norte: Pará, Rondônia e Tocantins; Nordeste: Bahia, Maranhão, Pernambuco e Piauí; Centro-Oeste: Distrito Federal, Goiás, Mato Grosso e Mato Grosso do Sul; Sudeste: Espírito Santo, Minas Gerais, Rio de Janeiro e São Paulo; e Sul: Paraná. Estes dados indicam que o papel de cada uma destas espécies na transmissão de patógenos deve ser reavaliado de acordo com seu novo status taxonômico. / Recent genetic, biological and morphological studies have demonstrated that Amblyomma cajennense is a complex of at least six distinct species, each species linked to a biogeographic area in the American continent. In this context, the present study aimed to perform morphological and molecular analyzes of adult ticks, previously identified as A. cajennense, deposited in the collections of ticks \"Coleção Nacional de Carrapatos\", the Faculty of Veterinary Medicine and Zootechny of the University of São Paulo and in the \"Coleção Acarológica do Instituto Butantan\" the Butantan Institute of São Paulo. Adicional tick specimens were obtained through fieldwork. Ticks were collected in the vegetation, domestic animals (horses, pigs) and road-killed wild animals (tapir, anteater) during three field expeditions, one in the northeast of the country between the municipalities of Bequimão/MA and Estrela do Norte/GO; one in the northwest of the country between the municipalities of Presidente Médici/RO and Vila Bela da Santíssima Trindade/MT; and a third one in the center-north of the country between the municipalities of Sinop/MT and Cuiabá/MT. The morphological and molecular results demonstrated the occurrence of at least two distinct species of ticks (A. cajennense sensu stricto and Amblyomma sculptum) of the A. cajennense species complex occurring in the Brazilian land. In general, the distribution of the species A. cajennense s. s. is confirmed in Brazil in three northernern states (Pará, Rondônia and Tocantins) one Northeast state (Maranhão) and one Midwest state (Mato Grosso). It is note worthy the findings of a single female of A. cajennense s. s. on a farm in the municipality of Porangatu, in the far north of the state of Goiás at the northern end of the state of Goiás, at the border with the state of Tocantins. The occurrence of A. sculptum is confirmed in the following Brazilian states Northern region: Pará, Rondônia and Tocantins; Northeastern region: Bahia, Maranhão, Piauí and Pernambuco; Midwester region: Distrito Federal, Goiás, Mato Grosso and Mato Grosso do Sul; Southeastern region: Espírito Santo, Minas Gerais, Rio de Janeiro and São Paulo; and Southern region: Paraná. These data indicate that the role of each of these species in pathogen transmission should be re-assessed according to its new taxonomic status.

Tularemia is a one of the most complex zoonotic diseases. Francisella tularensis McCoy and Chapin, the causative agent of tularemia is considered endemic in Texas, but outbreaks are rare and there are few human cases each year. Tularemia is listed as a Category A biological weapon and air samples are taken daily in select major metropolitan areas, including Houston, to monitor for its presence. I determined the potential risk for tularemia introduction and spread in southeast Texas through field surveillance for the pathogen and its major arthropod vector in the region, Amblyomma americanum (L.); completion of a habitat capability map for A. americanum, based on landscape analysis of the study area; and potential movement and long-term establishment of tularemia through development of a spatially explicit, agent-based, simulation model. Field and laboratory investigations resulted in the identification of two samples positive for F. tularensis. A feral cat tested positive for Type B tularemia using a new aptamer-based assay, and one sample returned positive in Amblyomma maculatum by polymerase chain reaction. This work sheds light on a complex host-pathogen-vector interaction in the rural to urban interface and establishes a framework for future tularemia field work and pathogen modeling in the rural to urban interface.

Tularemia is a one of the most complex zoonotic diseases. Francisella tularensis McCoy and Chapin, the causative agent of tularemia is considered endemic in Texas, but outbreaks are rare and there are few human cases each year. Tularemia is listed as a Category A biological weapon and air samples are taken daily in select major metropolitan areas, including Houston, to monitor for its presence. I determined the potential risk for tularemia introduction and spread in southeast Texas through field surveillance for the pathogen and its major arthropod vector in the region, Amblyomma americanum (L.); completion of a habitat capability map for A. americanum, based on landscape analysis of the study area; and potential movement and long-term establishment of tularemia through development of a spatially explicit, agent-based, simulation model. Field and laboratory investigations resulted in the identification of two samples positive for F. tularensis. A feral cat tested positive for Type B tularemia using a new aptamer-based assay, and one sample returned positive in Amblyomma maculatum by polymerase chain reaction. This work sheds light on a complex host-pathogen-vector interaction in the rural to urban interface and establishes a framework for future tularemia field work and pathogen modeling in the rural to urban interface.

Concern over the vector potential of the Gulf Coast tick, Amblyomma maculatum Koch, with the pathogen Ehrlichia ruminantium Dumler, causative agent of the disease heartwater, has increased the need for fundamental knowledge of tick ecology and behavior, specifically immature tick biology. Texas strain A. maculatum adult male ticks, known to emit attraction-aggregation-attachment pheromone (AAAP), were used to artificially simulate immature tick interaction with adults, in forced environments, on cattle. Artificial areas were grouped by treatment level, which were 1) aggregating, attached adult males, 2) aggregating attached adult females or 3) an empty area with no adults, as a control. Immature ticks were noted to be 6 times more likely to be aggregating in the AAAP treatment area when adult males were present. In the presences of either adult female ticks or no ticks at all, immature ticks were found to be attaching at random within the given area were they where permitted to feed. A second correlation of mortality was noted among immature ticks in the presence of AAAP emitting adult male ticks. In the permitted area where immature ticks could attach and feed, immature ticks were twice as likely to have survived to engorgement if adult male ticks were present in the area as well (53%). There was no difference in the survival rate among immature ticks if adult females were present or no adults at all, 26% and 21%, respectively. The study demonstrated that a significant attraction existed between immature ticks and attached adult males emitting AAAP.

Utilizou-se técnicas de geoprocessamento e imagens geradas pelo Sistema Landsat 7 - ETM+, para identificar áreas favoráveis ao crescimento das populações de Amblyomma cajennense e, conseqüentemente, o risco de infestação humana pelo carrapato no Município de Piracicaba, São Paulo, Brasil. As imagens de satélite permitiram determinar os valores de temperatura e do Índice de Vegetação por Diferença Normalizada (NDVI) que, em associação com as variáveis, densidade de eqüinos e modelo preditivo de distribuição de capivaras (Hydrochoerus hydrochaeris), foram utilizadas para construir um modelo de risco multivariado identificando assim áreas favoráveis ao crescimento de populações do carrapato. Verificou-se que a população humana exposta às regiões altamente desfavoráveis ou desfavoráveis ao crescimento de populações de A. cajennense é de, no mínimo, 70,14% podendo chegar a 96,16%. Por outro lado, de 0,04% a 15,23% da população está exposta a áreas favoráveis ou altamente favoráveis ao longo do ano. / Geoprocessing techniques and Landsat 7 - ETM+ images were used to identify suitable areas for the development of Amblyomma cajennense populations and the resulting risk of human infestation by that tick in Piracicaba, São Paulo, Brazil. Temperature and Normalized Difference Vegetation Index (NDVI) were calculated based on satellite images, and those data were later associated with horse density and a predictive model of spatial distribution of capybaras (Hydrochoerus hydrochaeris) to build a multi-variant risk model. It was observed that the human population exposed to extremely unsuitable or unsuitable areas ranges from 70.14% to 96.16%. On the other hand, 0.04% to 15.23% of the human population is exposed to suitable or extremely suitable areas throughout the year.

Typescript (photocopy) / 193 leaves : ill., maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Zoology, 1980

Made available in DSpace on 2014-06-11T19:27:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-05-22Bitstream added on 2014-06-13T20:57:20Z : No. of bitstreams: 1 monteiro_ger_me_jabo.pdf: 4718837 bytes, checksum: 348326537ee49fc7b15073f8d7e90dfd (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / No presente estudo avaliou-se o desenvolvimento de resistência a ninfas do ixodídeo Amblyomma cajennense, induzida por infestações controladas, e a possível existência de reatividade cruzada com Amblyomma hebraeum. Para tal, caprinos sem contato prévio com carrapatos, com seis meses de idade, machos ou fêmeas, foram infestados três vezes sucessivamente com ninfas de A. cajennense. Ademais, outro grupo de caprinos foi infestado nas mesmas condições com ninfas de A. hebraeum e colhidos soros para pesquisa de possível reatividade cruzada com A. cajennense. Observou-se que caprinos desenvolveram resistência apenas parcial a ninfas de A. cajennense, como demonstrado pela alteração significativa dos seguintes parâmetros biológicos das ninfas, em relação à primoinfestação: redução de 41,7% e 37,1% no peso de ingurgitamento, respectivamente na 2ª e 3ª infestações; aumento de 20% no período de ecdise e redução de 25,7% na taxa de ecdise, respectivamente nas 3ª e 2ª infestações. Não houve alteração no período de ingurgitamento nem na porcentagem de recuperação de ninfas com as infestações sucessivas. A reação cutânea induzida pelas ninfas de A. cajennense durante as infestações em caprinos caracterizou-se por infiltrado de células inflamatórias, predominantemente neutrófilos e basófilos, estas últimas envolvidas na imunidade a carrapatos por meio de hipersensibilidade basofílica cutânea. Células apresentadoras de antígeno, nomeadamente macrófagos, linfócitos B e células dendríticas foram detectadas por imunoistoquímica em linfonodos drenantes de locais de fixação dos carrapatos, em maior número nos linfonodos dos animais infestados... / This study evaluated the acquision of resistance against Amblyomma cajennense nymphs in naïve goats, induced by repeated and controlled infestations, and a possible cross-reactivity with A. hebraeum. Ten naive goats, of both sexes, aged six months were used throughout the experiment. Animals were infested artificially thrice, 30 days intervals between infestations. In addition, goats were infested at same conditions with the tick A. hebraeum as well. Sera from these animals were collected looking for possible cross-reactivity between antigens from these ixodids. It was observed that goats developed partially resistance to A. cajennense nymphs from the 1st infestation on as shown by changes in some biological parameters, as follows: increase of 41.7% and 37.1% in engorgement weight, respectively at the 2nd and 3rd infestations, decrease in 25.7% in nymph s ecdise rate and increase of 20% in ecdise period, respectively at the 3rd and 2nd infestations. It was not observed alterations in engorgement period and percentage of yielded nymphs. Biopsies of tick bite lesions induced by A. cajennense nymphs during infestations in goats were characterized by inflammatory reaction with cellular influx by neutrophils and basophils predominantly, being the last one involved in the well-known cutaneous basophilia. Antigen presenting cells like macrophages, B-lymphocytes and dendritic cells were detected by immunohistochemical analysis of lymph nodes draining tick infested areas. It should be stressed that these cells were found in higher numbers at lymph nodes from infested goats than from the naïve ones. Western blotting analysis of nymphal A. cajennense extracts revealed shared polypeptides (160, 90 and 16kDa) when used sera from goats infested with A. cajennense either A. hebraeum, indicating cross reactivity between these two tick species.