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1.
ScientificWorldJournal ; 2014: 347043, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24987729

RESUMO

Mortality models often have inbuilt identification issues challenging the statistician. The statistician can choose to work with well-defined freely varying parameters, derived as maximal invariants in this paper, or with ad hoc identified parameters which at first glance seem more intuitive, but which can introduce a number of unnecessary challenges. In this paper we describe the methodological advantages from using the maximal invariant parameterisation and we go through the extra methodological challenges a statistician has to deal with when insisting on working with ad hoc identifications. These challenges are broadly similar in frequentist and in Bayesian setups. We also go through a number of examples from the literature where ad hoc identifications have been preferred in the statistical analyses.


Assuntos
Modelos Estatísticos , Mortalidade , Algoritmos , Humanos
2.
BMC Vet Res ; 10: 90, 2014 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-24755093

RESUMO

BACKGROUND: The study evaluated the effect of New Neonatal Porcine Diarrhoea Syndrome (NNPDS) on average daily gain (ADG) and mortality and described the clinical manifestations in four herds suffering from the syndrome. NNPDS is a diarrhoeic syndrome affecting piglets within the first week of life, which is not caused by enterotoxigenic Escherichia coli (ETEC), Clostridium perfringens (C. perfringens) type A/C, Clostridium difficile (C. difficile), rotavirus A, coronavirus, Cystoisospora suis, Strongyloides ransomi, Giardia spp or Cryptosporidium spp. RESULTS: Piglets were estimated to have a negative ADG of 9 and 14 g when diarrhoeic for 1 day and >1 day respectively. However, if only diarrhoeic on the day of birth, no negative effect on ADG was seen. Piglets originating from severely affected litters were estimated to have a reduced ADG of 38 g. The study did not show an overall effect of diarrhoea on mortality, but herd of origin, sow parity, birth weight, and gender were significantly associated with mortality. In one of the herds, approximately 25% of the diarrhoeic piglets vs. 6% of the non-diarrhoeic piglets died, and 74% of necropsied piglets were diagnosed with enteritis. These findings indicate that the high mortality seen in this herd was due to diarrhoea. CONCLUSIONS: NNPDS negatively affected ADG in piglets, and even piglets that were diarrhoeic for one day only experienced a reduction in ADG. However, the study showed that diarrhoea restricted to the day of birth did not affect ADG and suggested this phenomenon to be unrelated to the syndrome. Since the diarrhoeal status of the litter had important effects on ADG, future research on NNPDS probably ought to focus on piglets from severely affected litters.The study showed important dissimilarities in the course of diarrhoea between the herds, and one herd was considerably more affected than the others. Within this herd, NNPDS seemed to be associated with a higher mortality, whereas in general the study did not show lethal effects of NNPDS.


Assuntos
Diarreia/veterinária , Doenças dos Suínos/mortalidade , Animais , Animais Recém-Nascidos/crescimento & desenvolvimento , Dinamarca/epidemiologia , Diarreia/epidemiologia , Diarreia/mortalidade , Diarreia/fisiopatologia , Feminino , Masculino , Prevalência , Suínos/crescimento & desenvolvimento , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/fisiopatologia , Síndrome , Aumento de Peso
3.
BMC Vet Res ; 9: 206, 2013 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-24119974

RESUMO

BACKGROUND: Neonatal diarrhoea is a frequent clinical condition in commercial swine herds, previously regarded to be uncomplicated to treat. However, since 2008 it seems that a new neonatal diarrhoeic syndrome unresponsive to antibiotics and common management practices has emerged. Routine laboratory examinations have not detected any pathogen related to this syndrome. The primary purpose of this study was to evaluate if well-known enteric pathogens could be associated with outbreaks of neonatal diarrhoea, thus question the hypotheses of a new syndrome. Furthermore, we wanted to evaluate macroscopic and microscopic findings associated with these outbreaks and if possible propose a preliminary piglet-level case-definition on syndrome New Neonatal Porcine Diarrhoea syndrome (NNPDS). RESULTS: Four well-managed herds experiencing neonatal diarrhoea with no previously established laboratory conclusion and suspected to suffer from New Neonatal Porcine Diarrhoea Syndrome, were selected. Within these herds, 51 diarrhoeic and 50 non-diarrhoeic piglets at the age of three to seven days were necropsied and subjected to histological and microbiological examination. Faeces were non-haemorrhagic. Neither enterotoxigenic E. coli, Clostridium perfringens type A or C, Clostridium difficile, rotavirus, coronavirus, Cryptosporidium spp, Giardia spp, Cystoisospora suis nor Strongyloides ransomi were associated with diarrhoea in the investigated outbreaks. Macroscopically, the diarrhoeic piglets were characterized by filled stomachs and flaccid intestines without mucosal changes. The predominant histological lesions were villous atrophy in jejunum and ileum. Epithelial lesions in colon were seen in one third of the case piglets. CONCLUSIONS: The results of the study supported the hypothesis that a new neonatal porcine diarrhoea was present in the investigated herds, since no known pathogen(s) or management factors could explain the diarrhoeal outbreaks. Based on the findings in the four herds the following case-definition of NNPDS was suggested: Non-haemorrhagic diarrhoea during the first week of life, without detection of known infectious pathogens, characterized by milk-filled stomachs and flaccid intestines at necropsy.


Assuntos
Diarreia/veterinária , Doenças dos Suínos/patologia , Animais , Animais Recém-Nascidos , Estudos de Casos e Controles , Dinamarca/epidemiologia , Diarreia/epidemiologia , Diarreia/patologia , Suínos , Doenças dos Suínos/epidemiologia
4.
Can J Vet Res ; 68(1): 66-70, 2004 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-14979438

RESUMO

The aim of the experimental study was to compare the humoral immune response and occurrence of adverse effects following single or multiple simultaneous vaccination of sows against Mycoplasma hyopneumonia, toxigenic Pasteurella multocida, and Actinobacillus pleuropneumoniae. In addition, passively transferred antibodies to piglets were studied until weaning at 3 weeks of age. Fever was seen in a few sows within the first 12 hours after the 1st and 2nd vaccination. No difference in the occurrence of other adverse effects was observed between groups. Antibody levels were significantly higher in vaccinated sows and their offspring compared with the control group. This was found to be independent of single or simultaneous vaccinations with the 3 vaccines. In conclusion, applying multiple vaccines simultaneously to sows appeared not to influence the occurrence of adverse effects or the sow's serum levels of antibodies at the time of farrowing, nor the offspring's serum levels up to 3 weeks of age.


Assuntos
Anticorpos Antibacterianos/análise , Vacinas Bacterianas/imunologia , Doenças dos Suínos/prevenção & controle , Vacinação/veterinária , Infecções por Actinobacillus/prevenção & controle , Infecções por Actinobacillus/veterinária , Actinobacillus pleuropneumoniae/imunologia , Animais , Animais Recém-Nascidos , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Imunidade Materno-Adquirida , Mycoplasma hyopneumoniae/imunologia , Infecções por Pasteurella/prevenção & controle , Infecções por Pasteurella/veterinária , Pasteurella multocida/imunologia , Pneumonia Suína Micoplasmática/prevenção & controle , Suínos , Resultado do Tratamento
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