Bayesian hierarchical models for disease mapping applied to contagious pathologies.

Disease mapping aims to determine the underlying disease risk from scattered epidemiological data and to represent it on a smoothed colored map. This methodology is based on Bayesian inference and is classically dedicated to non-infectious diseases whose incidence is low and whose cases distribution is spatially (and eventually temporally) structured. Over the last decades, disease mapping has received many major improvements to extend its scope of application: integrating the temporal dimension, dealing with missing data, taking into account various a prioris (environmental and population covariates, assumptions concerning the repartition and the evolution of the risk), dealing with overdispersion, etc. We aim to adapt this approach to model rare infectious diseases proposing specific and generic variants of this methodology. In the context of a contagious disease, the outcome of a primary case can in addition generate secondary occurrences of the pathology in a close spatial and temporal neighborhood; this can result in local overdispersion and in higher spatial and temporal dependencies due to direct and/or indirect transmission. In consequence, we test models including a Negative Binomial distribution (instead of the usual Poisson distribution) to deal with local overdispersion. We also use a specific spatio-temporal link in order to better model the stronger spatial and temporal dependencies due to the transmission of the disease. We have proposed and tested 60 Bayesian hierarchical models on 400 simulated datasets and bovine tuberculosis real data. This analysis shows the relevance of the CAR (Conditional AutoRegressive) processes to deal with the structure of the risk. We can also conclude that the negative binomial models outperform the Poisson models with a Gaussian noise to handle overdispersion. In addition our study provided relevant maps which are congruent with the real risk (simulated data) and with the knowledge concerning bovine tuberculosis (real data).

Bovine neutrophils in health and disease.

Bovine neutrophils have similarities to those of other species with respect to mechanisms of their activation and migration into tissue, modulation of immune responses and the balance between microbial killing and host tissue damage. However, bovine neutrophils have biochemical and functional differences from those of other species, which may yield insights about the comparative biology of neutrophils. Neutrophils play protective and harmful roles in the infectious diseases of cattle that occur at times of transition: respiratory disease in beef calves recently arrived to feedlots and mastitis and other diseases of postparturient dairy cows. An important research focus is the mechanisms by which risk factors for these diseases affect neutrophil function and thereby lead to disease and the prospect of genetic or pharmacologic improvement of disease resistance. Further, in keeping with the One Health paradigm, cattle can be considered a model for studying the role of neutrophils in naturally occurring diseases caused by host-adapted pathogens and are thus an intermediary between studies of mouse models and investigations of human disease. Finally, the study of bovine neutrophils is important for agriculture, to understand the pathogenesis of these production-limiting diseases and to develop novel methods of disease prevention that improve animal health and reduce the reliance on antimicrobial use.

Enfermidades do sistema digestório de bovinos da região semiárida do Brasil / Digestive diseases of cattle from the semiarid of Brazil

Os problemas digestivos são importantes causas de afecções em bovinos e estudos sobre a frequência de ocorrência destas na região semiárida do Brasil ainda não foram realizados. Objetivou-se com este trabalho obter informações sobre a ocorrência de doenças do sistema digestório em bovinos atendidos no Hospital Veterinário da Universidade Federal de Campina Grande no período de janeiro de 2000 a dezembro de 2014. No período do levantamento foram atendidos 1.202 bovinos, sendo 19,4% (233/1202) diagnosticados com enfermidades do sistema digestório. A taxa de letalidade das enfermidades foi 49,8% (116/233). As reticulites traumáticas e a indigestão vagal foram diagnosticadas, respectivamente, em 13,3%e 5,1% dos animais atendidos, sendo considerados distúrbios motores frequentes e de alta letalidade devido à gravidade das lesões, demora no atendimento clínico e imprecisão no diagnóstico. A obstrução ao fluxo da ingesta foi também uma condição identificada frequentemente, sendo ocasionada por obstruções esofágicas (4,3%), impactações no rúmen (11,7%), omaso e/ou abomaso (3,4%) e principalmente acidentes intestinais (26,2%), tendo a totalidade dos casos superado os distúrbios fermentativos da cavidade ruminorreticular. Actinobacilose (6,9%), actinomicose (3%) e paratuberculose (1,7%) foram as doenças infecciosas bacterianas diagnosticadas. As doenças infecciosas virais diagnosticadas foram a febre catarral maligna (4,3%), diarreia viral bovina e a doença das mucosas (3%). As doenças parasitárias foram também importantes causas de morbidade em bovinos jovens (9,4%) apesar dos sistemas de criação com baixa lotação e as condições climáticas da região não favorecerem a sobrevivência de parasitos gastrintestinais, demonstrando que não estão sendo implantadas medidas de controle adequadas para estas enfermidades. Os distúrbios motores da cavidade ruminorreticular, seguido das obstruções intestinais e das doenças infecciosas digestivas são os mais frequentes problemas digestivos de bovinos na região semiárida do Brasil. A ingestão de corpos estranhos é um dos mais graves problemas na região sendo necessário intenso trabalho de divulgação sobre medidas profiláticas. Além disso, medidas de controle e profilaxia de enfermidades infectocontagiosas como a diarreia viral bovina e a paratuberculose precisam ser divulgadas, pela possibilidade de disseminação destas nos rebanhos da região.(AU)

Digestive problems are important causes of diseases in cattle and studies on the frequency of its occurrence in the semiarid region of Brazil have not been conducted. The aim of this study was to acquire information on the occurrence of digestive diseases of cattle attended at the Veterinary Hospital of the Federal University of Campina Grande from January 2000 to December 2014. During the period of the survey 1,202 cattle were attended, from which 19.4% (233/1202) were diagnosed with digestive disorders. The lethality rate of the diseases was 49.8% (116/233). Traumatic reticulitis and vagal indigestion were diagnosed respectively in 13.3% e 5.1% of the animals treated being considered common and high lethality motor disorders, which were attributed to the severity of injuries, delay in the clinical care and inaccurate diagnoses. Obstruction of the intake flow, caused by esophageal obstruction (4.3%), rumen impactations (11.7%), omasum and/or abomasum impaction (3.4%), and especially intestinal accidents (26.2%) was a commonly identified condition, and its case totality exceeded the number cases of ruminorreticular cavity fermentative disorders. Actinobacillosis (6.9%), actinomycosis (3%) and paratuberculosis (1.7%) were the bacterial infectious diseases diagnosed, and the first was the most frequent. Viral infectious diseases diagnosed were malignant catarrhal fever (4.3%), bovine viral diarrhea and mucosal disease (3%). Despite the management systems with low animal density and climatic conditions of the region do not favor the survival of gastrointestinal parasites, parasitic diseases were also important causes of morbidity in young cattle (9.4%), suggesting that suitable control measures for those diseases have not been implemented Motor disorders of the ruminoreticular cavity, followed by intestinal obstructions and digestive infectious diseases are the most frequent digestive problems of cattle in the semi-arid region of Brazil. The ingestion of foreign bodies is one of the most serious problems in the region and intense work is needed to disseminate it on prophylactic measures. In addition, measures for the control and prophylaxis of infectious diseases such as bovine viral diarrhea and paratuberculosis need to be disclosed, due to the possibility of dissemination of these diseases in the herds of the region.(AU)