Epidemiología, diagnóstico y efecto de la presencia del virus de la leucosis bovina enzoótica en animales asintomáticos sobre parámetros productivos, reproductivos y sanitarios

La Leucosis Enzoótica Bovina (LEB) es una enfermedad producida por el Virus de la Leucosis Bovina (VLB) que afecta a sistemas productivos intensivos, principalmente bovinos de leche. La mayoría (~ 90%) de los animales infectados son portadores asintomáticos del virus y clínicamente sanos, siendo posible detectar la presencia de anticuerpos circulantes anti-VLB o del ADN proviral en los linfocitos infectados. En Uruguay, la principal importancia de esta infección radica en las restricciones en los mercados internacionales para la exportación de animales en pie, siendo un problema que se agrava cada vez más en nuestro país ya que conlleva a la permanencia de los animales seropositivos en los rodeos. Sin embargo, se desconoce con precisión el impacto real de la presencia del virus en portadores asintomáticos sobre parámetros productivos, reproductivos y sanitarios. Por lo tanto, el objetivo general de esta tesis doctoral es aportar conocimiento original vinculado a estos aspectos. En primer lugar, se determinó una tasa de seroconversión anual de 39.8% en un sistema de cría modelo de vaquillonas Holando en Uruguay, encontrándose un efecto negativo sobre los índices de concepción en vaquillonas infectadas con VLB. En segundo lugar, se encontraron asociaciones a campo entre animales seropositivos a VLB y la presencia de anticuerpos contra enfermedades de la reproducción; específicamente se encontró una asociación negativa con Herpesvirus bovino – 1 y Leptospira spp. Asimismo, al inmunizar contra Fiebre Aftosa y Clostridiosis bovinos infectados con VLB, se encontró una respuesta significativamente menor en los títulos de IgM e IgG1 contra Fiebre Aftosa. Finalmente, y en relación con el diagnóstico de VLB, se estandarizó una nueva herramienta molecular llamada Droplet Digital PCR que permitió detectar un 26% más de animales positivos que por la técnica de referencia de la OIE (nested PCR). Estos resultados buscan responder algunas preguntas desde el punto de vista práctico de este virus en producción bovina. A raíz de estos hallazgos se generaron nuevas hipótesis que deben ser profundizadas en futuros experimentos

Experimental evaluation of correlations used to calculate friction factor for turbulent flow in cylindrical pipes

Los sistemas hidráulicos encargados de la distribución de agua a los usuarios tienen un rol importante en su calidad de vida. Por ello, la determinación de manera precisa del factor de fricción en tuberías, es de gran importancia en el diseño de redes de distribución de agua debido a que influye directamente en el cálculo de caídas de presión (pérdidas de carga) en los sistemas hidráulicos. El objetivo del presente trabajo fue evaluar en forma experimental diferentes correlaciones que describan, mediante una forma explícita, el factor de fricción en una tubería bajo flujo turbulento y la correlación implícita de Colebrook-White. Esto se realizó mediante la comparación de valores numéricos predichos por las correlaciones respecto al valor experimental, encontrándose que la correlación de Colebrook-White predice el factor de fricción con menor porcentaje de error de las 27 correlaciones estudiadas. Para la solución de la ecuación de Colebrook-White se utilizó el método de Newton-Raphson, dado que ésta presenta una estructura recurrente que puede ser llevada a algoritmos y resuelta rápidamente mediante programas computacionales. En este trabajo se desarrolló una herramienta en lenguaje de programación C++ para resolver la ecuación de Colebrook-White.The hydraulic systems that distribute water to users have an important role in their quality of life. For this reason, the precise determination of the friction factor in pipes is of great importance in the design of water distribution networks because it directly influences the calculation of pressure drop (head losses) in hydraulic systems. The objective of the present work was to evaluate in an experimental manner different correlations that describe, in an explicit form, the friction factor in a pipe under turbulent flow and the implicit Colebrook-White correlation. This was done by comparing the numerical values predicted by the correlations in regard to the experimental value, finding that the Colebrook-White correlation predicts the friction factor with the lowest error percentage among the 27 correlations studied. For the solution of the Colebrook-White equation the Newton-Raphson method was used, given that it presents a recurrent structure that can be taken to algorithms and quickly solved by computer programs. In this work, a tool was developed in the C ++ programming language to solve the Colebrook-White equation.Peer Reviewe

Efecto de la ozonoterapia en el <i>Protoparvovirus carnívoro</i> tipo 1

El Parvovirus canino tipo 2, actualmente reclasificado y denominado Protoparvovirus carnívoro tipo 1 (CPPV-1), es uno de los agentes virales infecciosos más importante como causante de muerte de cachorros caninos. Produce una profusa diarrea hemorrágica y el tratamiento consiste en administrar terapia de sostén, no existiendo un tratamiento antiviral especifico. La ozonoterapia se considera una pro-droga que activa el sistema antioxidante endógeno mostrando múltiples efectos beneficiosos, como inmunoestimulación e inactivación de patógenos como por ejemplo los virus desnudos mediante la peroxidación de las proteínas de la cápside. Por lo expuesto, el objetivo de este trabajo fue evaluar la eficacia de la ozonoterapia frente al CPPV-1 in vivo e in vitro. Se conformaron dos grupos al azar de 10 caninos naturalmente infectados. Ambos recibieron el tratamiento sintomático, y uno de los grupos recibió, concomitantemente, ozonoterapia por vía intrarrectal.Trabajo publicado en Cagliada, Maria del Pilar Lilia y Galosi, Cecilia Mónica (comps.). I Congreso de Microbiología Veterinaria. Libro de resúmenes. La Plata: Facultad de Ciencias Veterinarias, 2021.Facultad de Ciencias Veterinaria

Predicting PM2.5 and PM10 Levels during Critical Episodes Management in Santiago, Chile, with a Bivariate Birnbaum-Saunders Log-Linear Model

Improving air quality is an important environmental challenge of our time. Chile currently has one of the most stable and emerging economies in Latin America, where human impact on natural resources and air quality does not go unperceived. Santiago, the capital of Chile, is one of the cities in which particulate matter (PM) levels exceed national and international limits. Its location and climate cause critical conditions for human health when interaction with anthropogenic emissions is present. In this paper, we propose a predictive model based on bivariate regression to estimate PM levels, related to PM2.5 and PM10, simultaneously. Birnbaum-Saunders distributions are used in the joint modeling of real-world PM2.5 and PM10 data by considering as covariates some relevant meteorological variables employed in similar studies. The Mahalanobis distance is utilized to assess bivariate outliers and to detect suitability of the distributional assumption. In addition, we use the local influence technique for analyzing the impact of a perturbation on the overall estimation of model parameters. In the predictions, we check the categorization for the observed and predicted cases of the model according to the primary air quality regulations for PM

Responsabilidad penal adolescente : estudio critico tras la reforma incorporada por la ley 20.084

100 p.La responsabilidad penal adolescente constituía un tema pendiente en nuestra legislación desde la ratificación de la Convención de los Derechos del Niño en el año 1990, pues la normativa vigente en ese entonces, contenida básicamente en la ley Nº 16.618, no se adecuó a los lineamientos impuestos por el derecho internacional, quedando al descubierto una serie de infracciones. Por lo anterior,luego de 15 años, se promulgó la ley 20.084 con vigencia desde junio de 2007. Los objetivos de esta ley son básicamente: el interés superior del niño, el reconocimiento de éste como sujeto de derechos y su consecuente responsabilidad, la especialidad del sistema de justicia y de sanciones y demás garantías procesales y penales. Por lo tanto, el objeto de la presente investigación es determinar si, a un año del funcionamiento de esta ley, tales postulados han sido completamente satisfechos

Field evaluation of commercial vaccines against Infectious Bovine Rhinotracheitis (Ibr) Virus using different immunization protocols

Bovine alphaherpesvirus 1 is ubiquitous in cattle populations and is associated with several clinical syndromes, including respiratory disease, genital disease, infertility and abortions. Control of the virus in many parts of the world is achieved primarily through vaccination with either inactivated or live modified viral vaccines. The objective of this study was to evaluate the performance of four commercially available BoHV-1 vaccines commonly used in Central and South America. Animals were divided into eight groups and vaccinated on days 0 and 30. Groups 1 to 4 received two doses of four different BoHV-1 commercial vaccines (named A to D). Groups 5 and 6 received vaccine D plus a vaccine for either Clostridial or Food-and-Mouth-Disease (FMD), respectively. Group 7 received one dose of two different brands of reproductive vaccines. Serum samples were collected from all animals on days 0, 30 and 60 to evaluate neutralizing and isotype-specific (IgG1 and IgG2) antibodies. Of the four commercial vaccines evaluated, only vaccine A induced neutralizing antibodies to titers ≥ 1:8 in 13/15 (86%) of the animals 60 days post-vaccination. Levels of IgG2 antibody increased in all groups, except for group 2 after the first dose of vaccine B. These results show that only vaccine A induced significant and detectable levels of BoHV-1-neutralizing antibodies. The combination of vaccine D with Clostridial or FMD vaccines did not affect neutralizing antibody responses to BoHV-1. The antibody responses of three of the four commercial vaccines analyzed here were lower than admissible by vaccine A. These results may be from vaccination failure, but means to identify the immune signatures predictive of clinical protection against BoHV-1 in cattle should also be considered

Natural Association Between Bovine Leukemia Virus and Reproductive Infectious Diseases

Background: Enzootic bovine leukosis (EBL) is a widespread infectious disease caused by the bovine leukemia virus (BLV), which results in immune system dysfunction. The resulting immunosuppression may lead to an increased prevalence of other diseases. Dairy cows infected have altered immune function associated with decreased milk production and shortened lifespan and decreased immune response to immunization. BLV infection, however, is often asymptomatic, so any connection between subclinical infection and common reproductive diseases remains unknown. This study aimed todescribe the relationship between naturally occurring subclinical BLV and infectious reproductive diseases seroconversion in the field.Materials, Methods &amp; Results: The diseases investigated included Bovine viral diarrhoea (BVD), Bovine alfaherpesvirus 1 (BoHV-1), Bovine gammaherpesvirus 4 (BoHV-4), Chlamydiosis, Leptospirosis, Brucellosis and Neosporosis in dairy cattle. Six hundred fifty-five sera samples from the northern and south-central regions of Uruguay, from asymptomatic female Holstein and Holstein crosses without a history of vaccination against reproductive diseases were processed using reference diagnostic methods (Seronautalization, ELISA, MAT, Rose Bengal Plate test). The seroprevalence of BLV was 20.0%. Seroprevalence of reproductive diseases BVD, BoHV-1 and BoHV-4 were 99.3%, 41.2% and 27.3% of the populations, respectively, and the total seroprevalence of Leptospirosis, bovine Neospora caninum and Chlamydiosiswere 19.8%, 29.8% and 33.0% respectively. The results revealed positive associations between naturally contracted BLV and the presence of antibodies against BoHV-1 (P = 0.002), as well as between naturally contracted BLV and presence ofantibodies against Leptospira spp. (P = 0.028).Discussion: BLV infection can impact innate and adaptive immune system cells and alter the proper functioning of uninfected cells. BLV infection may also induce changes in the complex balance of cytokine expression, cell proliferation,and programmed cell death in T- and B-lymphocytes, which is critical for immune competence and effective response toinfectious challenges. The progression of BLV infection has a substantial effect on host defense mechanisms. Indeed, lowmagnitude serologic responses to a commercial foot-and-mouth disease vaccine and a J5 Escherichia coli vaccine have been observed. These results are supported by recent trial studies showing a reduced immune response to vaccination against BoHV-1 and Leptospira spp. in asymptomatic animals infected with BLV. These are 2 of the most prevalent infectious reproductive diseases in cattle worldwide, and our results provide evidence that a link between BLV and susceptibility to these diseases may exist. Although there is evidence of the co-occurrence of these diseases, it remains unknown whether there is a direct or indirect effect of BLV on infertility, embryonic loss, or abortion. Another possibility is that natural infection with these reproductive pathogens (BoHV-1, Leptospira, or others) promotes BLV expression, negatively affecting the farms where these pathogens are endemic. Considering the high seroprevalence of BLV in dairy herds in North and South America where the infection is endemic, it was explored BLV’s role as an immunosuppressant by quantifying its co-occurrence with diseases that affect reproductive performance in breeding herds. Future work should clarify the role of BLV and the co-occurring pathogens in causing infertility or abortions. Keywords: BLV, herpesvirus, Infectious Bovine Rhinotracheitis (IBR), Leptospirosis, reproductive performance.Introdução: A leucose enzoótica bovina (LEB) é uma doença infecciosa generalizada causada pelo vírus da leucemia bovina (BLV), que resulta em disfunção do sistema imunológico. A imunossupressão resultante pode levar a um aumento da prevalência de outras doenças.&nbsp; Vacas leiteiras infectadas com BLV têm função imunológica alterada associada à diminuição da produção de leite e redução da expectativa de vida e pode-se esperar uma resposta imune diminuída à imunização. A infecção pelo BLV, no entanto, geralmente é assintomática, portanto, qualquer conexão entre a infecção subclínica e as doenças reprodutivas comuns permanece desconhecida. Este estudo teve como objetivo descrever a relação entre BLV subclínica de ocorrência natural e soroconversão de doenças reprodutivas infecciosas no campo. Materiais, Métodos e Resultados: As doenças investigadas incluíram Diarreia viral bovina (BVD), Herpesvírus bovino tipo 1 (BoHV-1), Herpesvírus bovino tipo 4 (BoHV-4), Clamidiose, Leptospirose, Brucelose e Neosporose em gado leiteiro. Seiscentos e cinquenta e cinco amostras de soro das regiões norte e centro-sul do Uruguai, de fêmeas&nbsp; holandesas assintomáticas e cruzamnetos sem histórico de vacinação contra doenças reprodutivas foram processadas usando métodos diagnósticos de referência (Seronautalização, ELISA, MAT, Rose Bengal Plate test). A soroprevalência do BLV foi de 20,0%. A soroprevalência de doenças &nbsp;reprodutiva BVD, BoHV-1 e BoHV-4 foi de 99,3%, 41,2% e 27,3% das populações, respectivamente, e a soroprevalência total de Leptospirose, Neospora caninum bovino e Clamidiose foi de 19,8%, 29,8% e 33,0%, respectivamente. Os resultados revelaram associações positivas entre BLV naturalmente contraído e a presença de anticorpos contra BoHV-1 (p = 0,002), bem como entre BLV naturalmente contraído e presença de anticorpos contra Leptospira spp (p = 0,028). Discussão: A infecção pelo BLV pode afetar as células do sistema imunológico inato e adaptativo e alterar o funcionamento adequado das células não infectadas. &nbsp;A infecção por BLV também pode induzir alterações no equilíbrio complexo da expressão de citocinas, proliferação celular e morte celular programada em linfócitos T e B, o que é crítico para a competência imunológica e resposta eficaz a desafios infecciosos. &nbsp;A progressão da infecção pelo BLV tem um efeito substancial nos mecanismos de defesa do hospedeiro. De fato, foram observadas respostas sorológicas de baixa magnitude a uma vacina comercial contra a Febre Aftosa e a uma vacina contra J5 Escherichia coli. Estes resultados são apoiados por estudos experimentais recentes que mostram uma resposta imune reduzida à vacinação contra BoHV-1 e Leptospira spp em animais assintomáticos infectados com BLV. Essas são duas das doenças infecciosas reprodutivas mais prevalentes em bovinos em todo o mundo, e nossos resultados fornecem evidências de que pode existir uma ligação entre BLV e suscetibilidade a essas doenças. Embora haja evidências da co-ocorrência dessas doenças, ainda não se sabe se há um efeito direto ou indireto do BLV na infertilidade, perda embrionária ou aborto. Outra possibilidade é que a infecção natural com esses patógenos reprodutivos (BoHV-1, Leptospira ou outros) promova a expressão do BLV, afetando negativamente as fazendas onde esses patógenos são endêmicos. Considerando a alta soroprevalência do BLV em rebanhos leiteiros onde a infecção é endêmica, explorou-se o papel do BLV como imunossupressor, quantificando sua co-ocorrência com doenças que afetam o desempenho reprodutivo em rebanhos reprodutores. Trabalhos futuros devem esclarecer o papel do BLV e dos patógenos co-ocorrentes em causar infertilidade ou abortos

Puesta a punto de una PCR digital (<i>Droplet Digital</i> PCR) para diagnóstico y cuantificación de <i>Staphylococcus aureus</i> productor de mastitis en Uruguay

La mastitis bovina producida por Staphylococcus aureus genera grandes pérdidas económicas para el productor lechero. Las técnicas moleculares como la PCR nos han permitido realizar el diagnóstico de una gran variedad de patógenos en distintos tipos de muestras incluyendo la leche. En este contexto, la Droplet Digital PCR (ddPCR) es la última generación de PCR que permite poder amplificar y cuantificar patógenos partiendo de muestras muy complejas o poco concentradas ya que tiene una gran sensibilidad y precisión, comparando con las técnicas existentes (PCR convencional y PCR en tiempo real). El objetivo de este trabajo fue poner a punto una Droplet Digital PCR (ddPCR) para la detección y cuantificación de Staphylococcus aureus a partir de cultivos y de muestras de leche inoculados artificialmente. Partiendo de cultivos puros de la cepa de referencia S. aureus ATCC 6538, se realizó la extracción de ADN genómico que se diluyó de forma seriada en base 10 (-1 a la -6) para su posterior amplificación y cuantificación por ddPCR.Trabajo publicado en Cagliada, Maria del Pilar Lilia y Galosi, Cecilia Mónica (comps.). I Congreso de Microbiología Veterinaria. Libro de resúmenes. La Plata: Facultad de Ciencias Veterinarias, 2021.Facultad de Ciencias Veterinaria

Comparison between DNA detection in trigeminal nerve ganglia and serology to detect cattle infected with bovine herpesviruses types 1 and 5

Bovine herpesviruses (BoHVs) types 1 (BoHV-1) and 5 (BoHV-5) are alphaherpesviruses of major importance to the bovine production chain. Such viruses are capable of establishing latent infections in neuronal tissues. Infected animals tend to develop a serological response to infection; however, such response—usually investigated by antibody assays in serum—may eventually not be detected in laboratory assays. Nevertheless, serological tests such as virus neutralization (VN) and various enzyme-linked immunosorbent assays (ELISAs) are widely employed to check individual or herd status of BoHV infections. The correlation between detection of antibodies and the presence of viral nucleic acids as indicatives of infection in infected cattle has not been deeply examined. In order to investigate such correlation, 248 bovine serum samples were tested by VN to BoHV-1 and BoHV-5, as well as in a widely employed (though not type-differential) gB ELISA (IDEXX IBR gB X2 Ab Test) in search for antibodies to BoHVs. Immediately after blood withdrawal, cattle were slaughtered and trigeminal ganglia (TG) excised for DNA extraction and viral nucleic acid detection (NAD) by nested PCR. Neutralizing antibodies to BoHV-1 and/or BoHV-5 were detected in 44.8% (111/248) of sera, whereas the gB ELISA detected antibodies in 51.2% (127/248) of the samples. However, genomes of either BoHV-1, BoHV-5, or both, were detected in TGs of 85.9% (213/248) of the animals. These findings reveal that the assays designed to detect antibodies to BoHV-1 and/or BoHV-5 employed here may fail to detect a significant number of latently infected animals (in this study, 35.7%). From such data, it is clear that antibody assays are poorly correlated with detection of viral genomes in BoHV-1 and BoHV-5-infected animals