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

Serological studie of metapneumovirus, Ornithobacterium rhinotracheale, Mycoplasma synoviae and M. gallisepticum in broilers in Uruguay

Las afecciones respiratorias son causantes de importantes pérdidas económicas en la producción de parrilleros. Estas ocasionan la muerte de animales, perjuicios en la ganancia de peso y conversión, así como decomisos durante la faena. Nuestro país es un caso singular al no estar presente la Enfermedad de Newcastle y estar prohibido el uso de todo tipo de vacunación contra ésta en parrilleros. Por ello se seleccionaron para la investigación los Mycoplasmas gallisepticum y synoviae, el Metapneumovirus y el Ornithobacterium rhinotra- cheale. Entre octubre 2008 y abril 2009 se obtuvieron 1866 muestras de suero de parrilleros de 35 días que correspondían al 1% de las aves de cada lote. Las 17 granjas participantes se ubicaban en los Departamentos de Montevideo, Canelones y Lavalleja y pertenecían a 3 diferentes integraciones. La técnica utilizada fue ELISA con kits comerciales de IDEXX Laboratories. Resultaron positivos a Metapneumivirus 195 (10.45%), a Ornithobacterium rhinotracheale 47 (2.51 %), a Mycoplasma synoviae 23 (1.23%) y a Mycoplasma gallisepticum 11 (0.58%). Si consideramos como unidad el lote, resultaron positivos 70.58 %, 82.35 %, 52.94 % y 41.17 % a las respectivas afecciones. La evidencia serológica de Metapneumivirus y Ornithobacterium muestra una considerable difusión entre aves y lotes. Para ambos Mycoplasmas los positivos fueron escasos si lo comparamos a los diagnósticos clínicos que se efectúan.Respiratory diseases causes important economic losses in poultry due to increase mortality, poor performance parameter such as growth per day or feed conversion, and an increase of condemnation rates. In Uruguay it is forbidden the vaccination against New Castle disease because the country is considered as free of this disease. The purpose of this study is determinate the serological evidence of Avian Metapneumovirus, Ornhitobacterium rhinotracheale, Mycoplasma gallisepticum and Mycoplasma synoviae. During October of 2008 and April of 2009, 1866 serum samples were taken from 35 days old broilers corresponding to the 1% of the total broiler population of each group. The 17 sampled farms are located in the departments of Montevideo, Canelones and Lavalleja belonging to 3 different companies. The serum samples were analyzed by ELISA technique using IDEXX commercial kits. 195 (10,45%) serum samples were positive to Metapneumovirus, 47 (2,51%) were positive to ORT, 23 (1,23%) to Mycoplasma synoviae and 11 (0,58%) positives to Mycoplasma gallisepticum. If we consider the 17 sampled farms as a 100% the results were 70,58% ; 82,35% ; 52,94% and 41,17% respectively for each disease. The serological evidence of metapneumovirus and ORT shows a considerable diffusion between birds and groups. For both Mycoplasmas the positive serum samples were few compared with the positive clinical field diagnosis.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

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

Serological evidence of infection with Ornithobacterium rhinotracheale in broilers in Uruguay

Ornithobacterium rhinotracheale fue identificado como patógeno para las aves en pavos en Alemania durante 1981. Posteriormente se lo asocia a problemas respiratorios en patos y parrilleros. En América del Sur su presencia por aislamiento o serología está reportada en Brasil (1998), Perú (1999) y Argentina (2009 enviado a publicar).El interés en demostrar la eventual presencia de anticuerpos al patógeno en nuestro medio se relaciona a importantes pérdidas económicas registradas en la producción de parrilleros en otras áreas geográficas. Se obtuvieron 1870 muestras de sangre de parrilleros con 35 días de edad que correspondían al 1% de las aves de cada lote. Se sangraron 17 granjas ubicadas en Montevideo, Canelones y Lavalleja pertenecientes a 3 diferentes integraciones. La técnica utilizada fue ELISA con kits comerciales (IDEXX). Resultaron positivos 47 sueros correspondientes a 2.52% del total. De los 17 lotes estudiados, 14 tenían aves positivas (82,35%). Se encontraron positivos en las 3 integraciones.Los resultados demuestran por primera vez evidencia serológica de la presencia de Ornithobacterium rhinotracheale en parrilleros en nuestro país.In Germany during 1981 Ornhitobacterium rhinotracheale was isolated from the respiratory tracks of turkeys. Nowadays, ORT is considered a respiratory pathogen for poultry. In South America, ORT presence was determinate by serology or isolation in Brazil (1998), Peru (1999) and Argentina (2009 in press). The interest in determining the presence of antibodies against this pathogen it is related with the important economical looses in the broiler production due to respiratory diseases. 1870 blood samples were obtained from 35 days old broilers from 17 farms with 3 different origins (integrating companies) located in the cities of Montevideo, Canelones and Lavalleja corresponding to the 1% of the total broiler population of the 17 farms. The antibodies against ORT were quantified by an Enzyme-linked immunosorbent assay (ELISA) using commercial kits (IDEXX). 47 serum samples were positive corresponding to a 2,52 % of the total samples. Of the 17 farms in the study, 14 had positive results (82,35 %). Serological evidence was found in the 3 origins. (Integrating companies). This is the first serological evidence report of ORT in broilers in Uruguay.Facultad de Ciencias Veterinaria

Serological evidence of infection with Ornithobacterium rhinotracheale in broilers in Uruguay

Ornithobacterium rhinotracheale fue identificado como patógeno para las aves en pavos en Alemania durante 1981. Posteriormente se lo asocia a problemas respiratorios en patos y parrilleros. En América del Sur su presencia por aislamiento o serología está reportada en Brasil (1998), Perú (1999) y Argentina (2009 enviado a publicar).El interés en demostrar la eventual presencia de anticuerpos al patógeno en nuestro medio se relaciona a importantes pérdidas económicas registradas en la producción de parrilleros en otras áreas geográficas. Se obtuvieron 1870 muestras de sangre de parrilleros con 35 días de edad que correspondían al 1% de las aves de cada lote. Se sangraron 17 granjas ubicadas en Montevideo, Canelones y Lavalleja pertenecientes a 3 diferentes integraciones. La técnica utilizada fue ELISA con kits comerciales (IDEXX). Resultaron positivos 47 sueros correspondientes a 2.52% del total. De los 17 lotes estudiados, 14 tenían aves positivas (82,35%). Se encontraron positivos en las 3 integraciones.Los resultados demuestran por primera vez evidencia serológica de la presencia de Ornithobacterium rhinotracheale en parrilleros en nuestro país.In Germany during 1981 Ornhitobacterium rhinotracheale was isolated from the respiratory tracks of turkeys. Nowadays, ORT is considered a respiratory pathogen for poultry. In South America, ORT presence was determinate by serology or isolation in Brazil (1998), Peru (1999) and Argentina (2009 in press). The interest in determining the presence of antibodies against this pathogen it is related with the important economical looses in the broiler production due to respiratory diseases. 1870 blood samples were obtained from 35 days old broilers from 17 farms with 3 different origins (integrating companies) located in the cities of Montevideo, Canelones and Lavalleja corresponding to the 1% of the total broiler population of the 17 farms. The antibodies against ORT were quantified by an Enzyme-linked immunosorbent assay (ELISA) using commercial kits (IDEXX). 47 serum samples were positive corresponding to a 2,52 % of the total samples. Of the 17 farms in the study, 14 had positive results (82,35 %). Serological evidence was found in the 3 origins. (Integrating companies). This is the first serological evidence report of ORT in broilers in Uruguay.Facultad de Ciencias Veterinaria

Stochastic estimation for seroprevalence of infections laryngotracheitis virus in broilers in Uruguay

The objective of this study was to estimate the true seroprevalence of seropositive individual broilers against infectious laryngotracheitis virus in Uruguay using a Bayesian inference software based on Markov chain Monte Carlo technique. Seventeen farms were kept under investigation between 2008 and 2009. Each study flock was randomly selected at different farms recruited from the capital city Montevideo, Canelones and Lavalleja Departments. The required total sample size was determined by power analysis, and blood samples collected were analysed using a commercial ELISA for the detection of antibody to the pathogen mentioned above. The overall seroprevalence of the virus was estimated at 31.5% [95% Bayesian credible interval (16.8–49.2%); N = 1790]. Because none of the study broilers had been inoculated against the virus prior to sampling, most of these results could be ascribed to natural exposure by field viruses and/or vaccine viruses from neighbouring layers. It should be considered as further risk assessment for clarifying the suitable vaccines to prevent chicken population in Uruguay from the virus.El objetivo de este estudio fue estimar la real seroprevalencia de pollos parrilleros seropositivos contra el virus de la laringotraqueítis infecciosa en Uruguay, mediante el uso de un “software” de inferencia Bayesiana que aplica la metodología de Monte Carlo basado en Cadenas de Markov (MCMC). En la investigación se incluyeron diecisiete granjas entre los años 2008 y 2009. Cada galpón fue seleccionado al azar en granjas ubicadas en la ciudad capital, Montevideo, y en los Departamentos de Canelones y Lavalleja. El tamaño de muestra necesario fue determinado en base al poder estadístico del análisis, y las muestras de sangre recolectadas fueron analizadas utilizando un ELISA comercial para la detección de anticuerpos contra el patógeno mencionado anteriormente. La seroprevalencia total del virus fue estimada en 31.5% [95% intervalo de credibilidad Bayesiano (16.8–49.2%); N = 1790]. Debido a que ninguno de los individuos bajo estudio habían sido vacunado contra el virus previamente al muestreo, la mayoría de los resultados podrían ser atribuidos a la exposición natural al virus de campo y/o al virus vacunal de aves en galpones vecinos. Esto debería ser tenido en cuenta como un elemento adicional del análisis de riesgo en la adecuada selección de vacunas para prevenir el contagio del virus a la población de pollos en Uruguay

Flock-level seroprevalence against Ornithobacterium rhinotracheale among broilers in Uruguay

The objective of this study was to estimate the true prevalence of seropositive broiler flocks against Ornithobacterium rhinotracheale in Uruguay, South America. Seventeen farms of broiler chickens greater than 35 days of age were studied. The field investigation was conducted between October 2008 and April 2009. Individual-chicken sera and pooled sera (containing 10 individual-chicken sera each) were analyzed using a commercial ELISA for the detection of antibody against Ornithobacterium rhinotracheale in chicken serum. A total of 181 pooled samples from the study area representing 17 farms were examined. Fifty-four pools were classified as test positive, because they included at least one individual-chicken classified as positive. On the basis of deterministic approach, the estimates for the apparent prevalence and true prevalence at flock-level were 30% and 17%, respectively. The true prevalence estimate with the Bayesian model (stochastic approach) was slightly lower and having wider confidence intervals [11% (95% CI: 0%-32%)].Facultad de Ciencias Veterinaria

Assessing the seroprevalence against avian pneumovirus and Ornithobacterium rhinotracheale in broilers in Uruguay

The objective of this study was to estimate the true prevalence of individual chickens serologically test-positive against avian pneumovirus and Ornithobacterium rhinotracheale in Uruguay. Seventeen different broiler farms existed in three different provinces in Uruguay were recruited and the 1861 broilers were investigated. Individual-chicken sera were analyzed using a commercial enzyme-linked immunosorbent assay. The overall true seroprevalence was 1.9% [95% Bayesian Credible Interval (BCI): <1-7.4%] and less than 0.1% (95% BCI: 0-<0.1%) against avian pneumovirus and Ornithobacterium rhinotracheale, respectively. The result seroprevalence was relatively lower than that reported by other authors in a neighbouring country Argentina where the infection of these diseases was recently observed. This difference was discussed.Facultad de Ciencias Veterinaria