Submitted by (edna.saturno@ufrpe.br) on 2016-08-11T12:26:26Z No. of bitstreams: 1 Artur Cezar de Carvalho Fernandes.pdf: 332869 bytes, checksum: fbb2c1878e6222c62de730cbb70d1d09 (MD5) / Made available in DSpace on 2016-08-11T12:26:26Z (GMT). No. of bitstreams: 1 Artur Cezar de Carvalho Fernandes.pdf: 332869 bytes, checksum: fbb2c1878e6222c62de730cbb70d1d09 (MD5) Previous issue date: 2012-02-16 / The Enzootic Bovine Leukosis (EBL) is a threat to the health of cattle herds in the state of Pernambuco and improvement in the use of epidemiological tools to identify and eliminate outbreaks of the disease demands attention. The aim of this study was to evaluate the leukocyte count as an aid in the identification of outbreaks of EBL and sanitation of livestock, from tests performed to establish the prevalence of this insidious retrovirus and Bovine Tuberculosis (BT) in cattle raised in several cities in the state. Were submitted for the EBL´s serodiagnosis 1000 bovine samples originating from 33 herds, 920 of them being previously submitted to the tuberculin test. Approximately 70% (694/1000) of the bovine leukocyte counts were analyzed, and disregarded animals with inconclusive results to two diagnostic tests and the positive to the tuberculin test. Thus, 530 samples were divided into two experimental groups, according to the results of AGID: GI = white blood cell count of 379 seronegative cattle, and IGI = white blood cell count of 151 seropositive cattle. The prevalence of EBL and BT were 28% (282/1000) and 11% (99/920), respectively. Overall, the mean values of leukocytes were: total = 12.0 ± 4.7 and lymphocytes = 8.1 ± 5.4 (x103/mm3). Considering the experimental groups, the mean values of leukocytes in GI (total = 11.5 ± 3.8 and = 7.6 ± 5.1 lymphocytes x103/mm3) were significantly lower (p <0.05) than those of GII (total = 13.3 ± 6.3 and = 9.1 ± 5.9 lymphocytes x103/mm3). 30% (159/530) of cattle examined had leukocytosis due to lymphocytosis - LL (total leukocytes and lymphocytes larger than x103/mm3 12.1 and 8.4, respectively), with the higher frequency of GI animals (99/379) with this lymphoproliferative disorder than GII (60/151), however the average values of GII leukocyte (total = 18.6 ± 6.5 and lymphocytes = 14.0 ± 6.7 x103/mm3) were significantly higher (p <0.05) to GI (total = 15.9 ± 3.1 and lymphocytes = 12.1 ± 8.0 x103/mm3). Analyzing the cattle with LL and that had leukocyte values above the reference standard deviation (total = 15.0 = 12.7 x103/mm3 and lymphocytes, respectively), there wasn´t significant difference between GI (total = 19 , 9 = ± 3.5 and 15.8 ± 3.9 lymphocytes x103/mm3) and GII (total = 23.2 ± 7.4 and 19.2 ± 7.4 lymphocytes = x103/mm3). Cattle GI (seronegative) with LL (total> 15.0 and lymphocytes> 12.7 x103/mm3) were considered suspect because leukocyte counts did not differ significantly with those of GII (seropositive) with LL. It is concluded that with the VLB demonstration of interference in leukocyte counts of cattle examined and the identification of suspect cattle not detected by AGID, the leukocyte count lends itself as an auxiliary to the identification of outbreaks of LEB and sanitation of livesto / A Leucose Enzoótica dos Bovinos (LEB) é uma ameaça à saúde dos rebanhos bovinos do estado de Pernambuco e o aperfeiçoamento no uso de ferramentas epidemiológicas para identificação e eliminação de focos desta doença demanda atenção. O objetivo com a realização deste estudo foi avaliar a leucometria como um recurso auxiliar para a identificação de focos da LEB e saneamento dos rebanhos, a partir de ensaios realizados para estabelecer a prevalência dessa insidiosa retrovirose e da Tuberculose Bovina (TB) em rebanhos criados em vários municípios do estado. Foram submetidas ao sorodiagnóstico para LEB amostras de 1.000 bovinos procedentes de 33 rebanhos, sendo 920 deles submetidos previamente ao teste da tuberculina (TCC). Em aproximadamente 70% (694/1000) dos bovinos foram realizadas análises leucométricas, sendo desconsiderados das mesmas os animais com resultados inconclusivos aos dois testes diagnósticos e os positivos ao teste da tuberculina. Desta forma, 530 amostras foram distribuídas em dois grupos experimentais, em função dos resultados à IDGA: GI = leucogramas de 379 bovinos soronegativos; e GII = leucogramas de 151 bovinos soropositivos. As prevalências da LEB e TB foram 28% (282/1000) e 11% (99/920), respectivamente. Globalmente, os valores médios dos leucócitos foram: totais = 12,0 ± 4,7 e linfócitos = 8,1 ± 5,4 (x103/mm3). Considerando os grupos experimentais, os valores médios dos leucócitos do GI (totais = 11,5 ± 3,8 e linfócitos = 7,6 ± 5,1 x103/mm3) foram significativamente menores (p<0,05) do que os do GII (totais = 13,3 ± 6,3 e linfócitos = 9,1 ± 5,9 x103/mm3). Dentre os bovinos examinados 30% (159/530) apresentaram leucocitose por linfocitose – LL (leucócitos totais e linfócitos maiores do que 12,1 e 8,4 x103/mm3, respectivamente), tendo o GI maior frequência de animais (99/379) com esta disfunção linfoproliferativa do que o GII (60/151), contudo os valores leucométricos médios do GII (totais = 18,6 ± 6,5 e linfócitos = 14,0 ± 6,7 x103/mm3) foram significativamente superiores (p<0,05) aos do GI (totais = 15,9 ± 3,1 e linfócitos = 12,1 ± 8,0 x103/mm3). Analisando os bovinos portadores de LL e que apresentaram os valores leucométricos acima do limite tolerável de referência (totais = 15,0 e linfócitos = 12,7 x103/mm3, respectivamente), não foi observada diferença significativa entre os grupos GI (totais = 19,9 ± 3,5 e linfócitos = 15,8 ± 3,9 x103/mm3) e GII (totais = 23,2 ± 7,4 e linfócitos = 19,2 ± 7,4 x103/mm3). Bovinos do GI (soronegativos) portadores de LL (totais > 15,0 e linfócitos > 12,7 x103/mm3) foram considerados suspeitos, pois não apresentaram diferença leucométrica significativa com os do GII (soropositivos) portadores de LL. Conclui-se que, com a demonstração da interferência do VLB no leucograma dos bovinos examinados e com a identificação de bovinos suspeitos não detectados pela IDGA, a leucometria se presta como recurso auxiliar para a identificação de focos da LEB e saneamento dos rebanhos.

Pas de résumé en français / Malaria is a devastating global health problem that affected 219 million people and caused 660,000 deaths in 2010. Inaccurate estimation of the level of infection may have adverse clinical and therapeutic implications for patients, and for epidemiological endpoint measurements. The level of infection, expressed as the parasite density (PD), is classically defined as the number of asexual parasites relative to a microliter of blood. Microscopy of Giemsa-stained thick blood smears (TBSs) is the gold standard for parasite enumeration. Parasites are counted in a predetermined number of high-power fields (HPFs) or against a fixed number of leukocytes. PD estimation methods usually involve threshold values; either the number of leukocytes counted or the number of HPFs read. Most of these methods assume that (1) the distribution of the thickness of the TBS, and hence the distribution of parasites and leukocytes within the TBS, is homogeneous; and that (2) parasites and leukocytes are evenly distributed in TBSs, and thus can be modeled through a Poisson-distribution. The violation of these assumptions commonly results in overdispersion. Firstly, we studied the statistical properties (mean error, coefficient of variation, false negative rates) of PD estimators of commonly used threshold-based counting techniques and assessed the influence of the thresholds on the cost-effectiveness of these methods. Secondly, we constituted and published the first dataset on parasite and leukocyte counts per HPF. Two sources of overdispersion in data were investigated: latent heterogeneity and spatial dependence. We accounted for unobserved heterogeneity in data by considering more flexible models that allow for overdispersion. Of particular interest were the negative binomial model (NB) and mixture models. The dependent structure in data was modeled with hidden Markov models (HMMs). We found evidence that assumptions (1) and (2) are inconsistent with parasite and leukocyte distributions. The NB-HMM is the closest model to the unknown distribution that generates the data. Finally, we devised a reduced reading procedure of the PD that aims to a better operational optimization and a practical assessing of the heterogeneity in the distribution of parasites and leukocytes in TBSs. A patent application process has been launched and a prototype development of the counter is in process.

Malaria is a devastating global health problem that affected 219 million people and caused 660,000 deaths in 2010. Inaccurate estimation of the level of infection may have adverse clinical and therapeutic implications for patients, and for epidemiological endpoint measurements. The level of infection, expressed as the parasite density (PD), is classically defined as the number of asexual parasites relative to a microliter of blood. Microscopy of Giemsa-stained thick blood smears (TBSs) is the gold standard for parasite enumeration. Parasites are counted in a predetermined number of high-power fields (HPFs) or against a fixed number of leukocytes. PD estimation methods usually involve threshold values; either the number of leukocytes counted or the number of HPFs read. Most of these methods assume that (1) the distribution of the thickness of the TBS, and hence the distribution of parasites and leukocytes within the TBS, is homogeneous; and that (2) parasites and leukocytes are evenly distributed in TBSs, and thus can be modeled through a Poisson-distribution. The violation of these assumptions commonly results in overdispersion. Firstly, we studied the statistical properties (mean error, coefficient of variation, false negative rates) of PD estimators of commonly used threshold-based counting techniques and assessed the influence of the thresholds on the cost-effectiveness of these methods. Secondly, we constituted and published the first dataset on parasite and leukocyte counts per HPF. Two sources of overdispersion in data were investigated: latent heterogeneity and spatial dependence. We accounted for unobserved heterogeneity in data by considering more flexible models that allow for overdispersion. Of particular interest were the negative binomial model (NB) and mixture models. The dependent structure in data was modeled with hidden Markov models (HMMs). We found evidence that assumptions (1) and (2) are inconsistent with parasite and leukocyte distributions. The NB-HMM is the closest model to the unknown distribution that generates the data. Finally, we devised a reduced reading procedure of the PD that aims to a better operational optimization and a practical assessing of the heterogeneity in the distribution of parasites and leukocytes in TBSs. A patent application process has been launched and a prototype development of the counter is in process.