Transmission electron microscopy applications for microbiological diagnosis

La microscopía electrónica de transmisión (MET) puede ser usada para el diagnóstico de enfermedades de origen microbiana, aunque su principal aplicación es en investigación. La MET provee detalles ultraestructurales, los cuales son útiles para la identificación de virus, bacterias, parásitos y hongos. El mayor aporte de la MET es en el diagnóstico rápido de enfermedades víricas. Mediante este instrumento, se pueden examinar diferentes tipos de muestras clínicas: sangre, heces, orina, biopsias, fluidos corporales, etc. En este trabajo se describen los métodos utilizados para la recolección, preparación y observación de las diferentes muestras y la aplicación de técnicas de inmunomicroscopía electrónica. Si bien la MET es un método muy útil en el diagnóstico rápido y la investigación de casos nuevos de origen infeccioso, la explotación completa de su potencial requiere de una aplicación temprana y coordinada con otros procedimientos de diagnóstico. En conclusión, la MET es una herramienta valiosa de diagnóstico microbiológico tanto en medicina humana como en veterinaria y su alcance se puede incrementar con la aplicación de métodos inmunológicos.Transmission electron microscopy (TEM) can be an important instrument in microbiology as well as in diagnosis and research. The TEM provides ultrastructural details witch are useful for the parasitological, bacteriological and mycological agents identification, but it is particularity valuable in the rapid diagnosis in viral illness. It can be applied to many body samples: blood, fecal samples, urinal, fluids, etc. Details for sample collection, preparation and examination are given. TEM can be a useful method for rapid diagnosis and investigation of new and unusual cases of infectious origin. However, full exploitation of it potential requires early and coordinated application of TEM with other diagnostic procedures. In conclusion, TEM is a valuable stool in the microbiologic diagnosis as well as in human medicine and veterinary and it can be to enhance with the application of immunologic techniques.Facultad de Ciencias Veterinaria

Transmission electron microscopy applications for microbiological diagnosis

La microscopía electrónica de transmisión (MET) puede ser usada para el diagnóstico de enfermedades de origen microbiana, aunque su principal aplicación es en investigación. La MET provee detalles ultraestructurales, los cuales son útiles para la identificación de virus, bacterias, parásitos y hongos. El mayor aporte de la MET es en el diagnóstico rápido de enfermedades víricas. Mediante este instrumento, se pueden examinar diferentes tipos de muestras clínicas: sangre, heces, orina, biopsias, fluidos corporales, etc. En este trabajo se describen los métodos utilizados para la recolección, preparación y observación de las diferentes muestras y la aplicación de técnicas de inmunomicroscopía electrónica. Si bien la MET es un método muy útil en el diagnóstico rápido y la investigación de casos nuevos de origen infeccioso, la explotación completa de su potencial requiere de una aplicación temprana y coordinada con otros procedimientos de diagnóstico. En conclusión, la MET es una herramienta valiosa de diagnóstico microbiológico tanto en medicina humana como en veterinaria y su alcance se puede incrementar con la aplicación de métodos inmunológicos.Transmission electron microscopy (TEM) can be an important instrument in microbiology as well as in diagnosis and research. The TEM provides ultrastructural details witch are useful for the parasitological, bacteriological and mycological agents identification, but it is particularity valuable in the rapid diagnosis in viral illness. It can be applied to many body samples: blood, fecal samples, urinal, fluids, etc. Details for sample collection, preparation and examination are given. TEM can be a useful method for rapid diagnosis and investigation of new and unusual cases of infectious origin. However, full exploitation of it potential requires early and coordinated application of TEM with other diagnostic procedures. In conclusion, TEM is a valuable stool in the microbiologic diagnosis as well as in human medicine and veterinary and it can be to enhance with the application of immunologic techniques.Facultad de Ciencias Veterinaria

Simulation models for estimating optimal vaccination timing for infectious bursal disease in broiler chickens in Paraguay

This study shows the results of estimating optimal vaccination timing for infectious bursal disease in broiler chickens in Paraguay, using spreadsheet simulation models.Fourteen flocks of broiler chicks were kept under observation.Sera were collected from randomly-selected 20 chicks per flock at 1, 4 and 8 days of age, and assayed by a commercial Enzyme-linked Immunosorbent Assay (ELISA) to evaluate Maternally Derived Antibody (MDA) titres.Deterministic (an age-based estimation method called the Deventer formula) and stochastic (through inclusion of uncertainty in the parameters) models were developed with the data.In the deterministic models, all the estimated optimal vaccination timings of each flock at the three sampling time points were between 16 and 24 days of age.In the stochastic models, each of the median optimal vaccination timings was estimated later than the corresponding point-estimate timing, generated by the deterministic version.Uniformity of the MDA titre distribution in the flocks was considered in relation to the number of vaccinations required.The ELISA results provide only a rough indication, in the case of deterministic model in particular.A stochastic version of the same model, in conjunction with the use of a concept of uniformity might give a solution to the problem.Facultad de Ciencias Veterinaria

Simulation models for estimating optimal vaccination timing for infectious bursal disease in broiler chickens in Paraguay

This study shows the results of estimating optimal vaccination timing for infectious bursal disease in broiler chickens in Paraguay, using spreadsheet simulation models.Fourteen flocks of broiler chicks were kept under observation.Sera were collected from randomly-selected 20 chicks per flock at 1, 4 and 8 days of age, and assayed by a commercial Enzyme-linked Immunosorbent Assay (ELISA) to evaluate Maternally Derived Antibody (MDA) titres.Deterministic (an age-based estimation method called the Deventer formula) and stochastic (through inclusion of uncertainty in the parameters) models were developed with the data.In the deterministic models, all the estimated optimal vaccination timings of each flock at the three sampling time points were between 16 and 24 days of age.In the stochastic models, each of the median optimal vaccination timings was estimated later than the corresponding point-estimate timing, generated by the deterministic version.Uniformity of the MDA titre distribution in the flocks was considered in relation to the number of vaccinations required.The ELISA results provide only a rough indication, in the case of deterministic model in particular.A stochastic version of the same model, in conjunction with the use of a concept of uniformity might give a solution to the problem.Facultad de Ciencias Veterinaria

Ultrastructural study of the coypo (Myocastor coypus) adenohypophysis

Por nuestro conocimiento no existen poblaciones concernientes a la ultraestructura de la adenohipófisis del Coipo. Este estudio tiene por objeto describir la estructura fina de las diferentes poblaciones celulares en la Pars distalis de la hipófisis del coipo adulto normal mediante técnicas convencionales para microscopía electrónica de transmisión: fijación en glutaraldehído post fijación en osmio e inclusión en resinas epoxy. Se emplearan 4 coipos machos y 4 hembras adultos mantenidos bajo condiciones naturales de luz, agua y alimento ad libitum. Se pudieron distinguir 5 tipos de células granuladas y 2 tipos de células no granuladas teniendo en cuenta principalmente la presencia de los gránulos de secreción y sus características. Las presentes observaciones efectuadas por primera vez en la adenohipófisis del coipo abren el camino para ampliar la información con nuevos estudios, especialmente basados en la inmunohistoquímica.The fine structure of the Myocastor coypus (coypu) adenohypophysis was studied by conventional techniques by transmission electron microscopy The material was fixed in glutaraldehyde post-fixed in osmium tetroxide and embedded in epoxy resins Five types of granulated cells as well as two types of agranular cells could be identified taking into account mainly the present and characteristics of their secretory granules When these cells were compared to those previously described in other mammals such as humans rats and mice somatotrophic and gonadotrophic cells were fairly recognized However the possibility of detecting other cell types without the use of immunocytochemical methods was less reliable to the species studied the presence of highly developed population of follicular agranular cell must be emphasized The present observations, made for the first time in the coypo adenohypophysis would open the way by further studies on the field especially those based in immunohistochemistry.Facultad de Ciencias Veterinaria

Avian Metapneumovirus: Review of Etiological, Clinical, Anatomopathological and Epidemiological Aspects

El Pneumovirus aviar (APV) es un patógeno viral de aves, que se ha asociado a infecciones del tracto respiratorio superior. El APV ha sido reclasificado y, junto con el Metapneumovirus humano (hMPV), fue asignado al género Metapneumovirus, motivo por el cual se lo denomina actualmente Metapneumovirus aviar (aMPV). Fue descripto por primera vez en 1978 en Sudáfrica. Luego se hizo presente en Europa, África, Medio Oriente y EE.UU. Fue clasificado en cuatro subtipos denominados: A, B, C y D. Si bien en pavos la enfermedad que provoca es grave, en pollos su rol como patógeno primario está menos aclarado. Se presenta junto con otros agentes en afecciones del aparato respiratorio y también formando parte de una entidad conocida como sindrome de cabeza hinchada. Los pollos pueden tener anticuerpos, incluso sin haber presentado signos clínicos. El mecanismo de transmisión requiere del contacto directo entre las aves. Su diseminación a grandes distancias es incierta, pero se postula que las aves silvestres son probables eslabones de la cadena. Generalmente, el diagnóstico se basa en pruebas serológicas, siendo la más utilizada la prueba de ELISA. En Argentina, se estima que este virus estaría presente pues se han detectado anticuerpos en sueros provenientes de aves en sistemas de cría comercial, pero hasta el momento no hay reportes de aislamiento del virus ni de su detección molecular.The Avian pneumovirus (APV) is a viral pathogen of birds, which has been associated with upper respiratory tract infections. Along with the Human metapneumovirus (hMPV), APV was placed in the genus Metapneumovirus. That is why it is currently called Avian metapneumovirus (aMPV). It was first reported in 1978 in South Africa. Then it was detected in Europe, Africa, Middle East and USA. It was classified into four subgroups called: A, B, C and D. While it causes a severe disease in turkeys, in chickens its role as a primary pathogen is less clear. It causes respiratory symptoms along with other agents and it also takes part of an entity known as swollen head syndrome. Chickens may have antibodies, without exhibiting signology. Transmission requires direct contact among birds. Its spread over long distances is uncertain, but wild birds are postulated as probable chain links. The diagnosis is usually based on serological tests, most commonly ELISA test. In Argentina its presence is estimated by antibodies detected in sera from commercial poultry, but there are no reports of isolation, or molecular detection.Facultad de Ciencias Veterinaria

Avian Metapneumovirus: Review of Etiological, Clinical, Anatomopathological and Epidemiological Aspects

El Pneumovirus aviar (APV) es un patógeno viral de aves, que se ha asociado a infecciones del tracto respiratorio superior. El APV ha sido reclasificado y, junto con el Metapneumovirus humano (hMPV), fue asignado al género Metapneumovirus, motivo por el cual se lo denomina actualmente Metapneumovirus aviar (aMPV). Fue descripto por primera vez en 1978 en Sudáfrica. Luego se hizo presente en Europa, África, Medio Oriente y EE.UU. Fue clasificado en cuatro subtipos denominados: A, B, C y D. Si bien en pavos la enfermedad que provoca es grave, en pollos su rol como patógeno primario está menos aclarado. Se presenta junto con otros agentes en afecciones del aparato respiratorio y también formando parte de una entidad conocida como sindrome de cabeza hinchada. Los pollos pueden tener anticuerpos, incluso sin haber presentado signos clínicos. El mecanismo de transmisión requiere del contacto directo entre las aves. Su diseminación a grandes distancias es incierta, pero se postula que las aves silvestres son probables eslabones de la cadena. Generalmente, el diagnóstico se basa en pruebas serológicas, siendo la más utilizada la prueba de ELISA. En Argentina, se estima que este virus estaría presente pues se han detectado anticuerpos en sueros provenientes de aves en sistemas de cría comercial, pero hasta el momento no hay reportes de aislamiento del virus ni de su detección molecular.The Avian pneumovirus (APV) is a viral pathogen of birds, which has been associated with upper respiratory tract infections. Along with the Human metapneumovirus (hMPV), APV was placed in the genus Metapneumovirus. That is why it is currently called Avian metapneumovirus (aMPV). It was first reported in 1978 in South Africa. Then it was detected in Europe, Africa, Middle East and USA. It was classified into four subgroups called: A, B, C and D. While it causes a severe disease in turkeys, in chickens its role as a primary pathogen is less clear. It causes respiratory symptoms along with other agents and it also takes part of an entity known as swollen head syndrome. Chickens may have antibodies, without exhibiting signology. Transmission requires direct contact among birds. Its spread over long distances is uncertain, but wild birds are postulated as probable chain links. The diagnosis is usually based on serological tests, most commonly ELISA test. In Argentina its presence is estimated by antibodies detected in sera from commercial poultry, but there are no reports of isolation, or molecular detection.Facultad de Ciencias Veterinaria

Avian Metapneumovirus: Review of Etiological, Clinical, Anatomopathological and Epidemiological Aspects

El Pneumovirus aviar (APV) es un patógeno viral de aves, que se ha asociado a infecciones del tracto respiratorio superior. El APV ha sido reclasificado y, junto con el Metapneumovirus humano (hMPV), fue asignado al género Metapneumovirus, motivo por el cual se lo denomina actualmente Metapneumovirus aviar (aMPV). Fue descripto por primera vez en 1978 en Sudáfrica. Luego se hizo presente en Europa, África, Medio Oriente y EE.UU. Fue clasificado en cuatro subtipos denominados: A, B, C y D. Si bien en pavos la enfermedad que provoca es grave, en pollos su rol como patógeno primario está menos aclarado. Se presenta junto con otros agentes en afecciones del aparato respiratorio y también formando parte de una entidad conocida como sindrome de cabeza hinchada. Los pollos pueden tener anticuerpos, incluso sin haber presentado signos clínicos. El mecanismo de transmisión requiere del contacto directo entre las aves. Su diseminación a grandes distancias es incierta, pero se postula que las aves silvestres son probables eslabones de la cadena. Generalmente, el diagnóstico se basa en pruebas serológicas, siendo la más utilizada la prueba de ELISA. En Argentina, se estima que este virus estaría presente pues se han detectado anticuerpos en sueros provenientes de aves en sistemas de cría comercial, pero hasta el momento no hay reportes de aislamiento del virus ni de su detección molecular.The Avian pneumovirus (APV) is a viral pathogen of birds, which has been associated with upper respiratory tract infections. Along with the Human metapneumovirus (hMPV), APV was placed in the genus Metapneumovirus. That is why it is currently called Avian metapneumovirus (aMPV). It was first reported in 1978 in South Africa. Then it was detected in Europe, Africa, Middle East and USA. It was classified into four subgroups called: A, B, C and D. While it causes a severe disease in turkeys, in chickens its role as a primary pathogen is less clear. It causes respiratory symptoms along with other agents and it also takes part of an entity known as swollen head syndrome. Chickens may have antibodies, without exhibiting signology. Transmission requires direct contact among birds. Its spread over long distances is uncertain, but wild birds are postulated as probable chain links. The diagnosis is usually based on serological tests, most commonly ELISA test. In Argentina its presence is estimated by antibodies detected in sera from commercial poultry, but there are no reports of isolation, or molecular detection.Facultad de Ciencias Veterinaria

Flock-level seroprevalence against avian pneumovirus amongst uruguayan broiler chickens

The objective of this study was to estimate the true prevalence of seropositive broiler chickens against avian pneumovirus at flock-level in Uruguay, using the Rogan-Gladen estimator in conjunction with Bayesian inference. A total of 181 pooled samples (consisting of 10 individual-chicken sera each) from the study area were examined with the enzyme-linked immunosorbent assay. All individual-chicken samples in the pools were also examined with the same assay. Forty-four pools were classified as test positive, because they included at least one individual-chicken classified as positive. The estimates for the deterministic (Rogan-Gladen approach) and stochastic (Bayesian approach) true prevalence were 30.9% [95% confidence interval (CI): 26.8-35.0%] and 31.4% (95% CI: 15.4-49.5%), respectively.Facultad de Ciencias Veterinaria

Comparison of the management characteristics of sero-positive and negative chickens against avian pneumovirus in Uruguay

The objective of this study was to investigate the risk factors, especially for management characteristics associated with the seropositivity of avian pneumovirus in broiler chickens Uruguay. Seventeen farms of broiler chickens (35 days of age) were studied from October 2008 to April 2009, comprised data collection through questionnaire intetviews for each study farm, in combination with blood sample collections for each chicken (n = 1861). Sera were analyzed using a commercial enzyme-linked immunosorbent assay. Univariate and multivariate analyses were used to describe the differences between the two chicken groups categorized according to seropositivity. Percentages of test positive were highly variable between the study farms (0.81%) on the basis of different sample sizes (30-224) The final multivariate logistic regression model indicated that five different study farms were less likely to have seropositive-chickens against avian pneumovirus compared with the reference farm (81% of test positive). Chickens introduced from the two unique hatcheries were less likely to be seropositive in comparison with chickens with no hatchery information.Facultad de Ciencias Veterinaria