Identification of genogroups of Infectious Bursal Disease Virus in poultry farms at Colombia / Identificación de genogrupos del virus de la enfermedad de gumboro en granjas avícolas en colombia

RESUMEN El virus de la enfermedad de Gumboro (IBDV) es un avibirnavirus con genoma dsARN que presenta altas tasas de mutación y recombinación. A pesar del efecto inmunosupresor en aves y la frecuencia con que ocurre la infección por este agente en el país son pocos los estudios que caracterizan los cuadros clínicos y se desconoce cuáles son los genogrupos circulantes. Esta investigación tuvo como objetivo determinar la frecuencia de lesiones histopatológicas en órganos del sistema inmune e identificar los genogrupos del IBDV en aves comerciales de Colombia. Para determinar la frecuencia de presentación de lesiones en órganos del sistema inmune se analizaron 381 casos clínicos de las bases de datos del Laboratorio de Patología Aviar (LPA) de la Universidad Nacional de Colombia, sede Bogotá (periodo 2016-2018). Asimismo, se secuenciaron los productos de RT-PCR del gen que codifica para la proteína viral VP2 provenientes de 35 muestras de bursas de Fabricio. Como resultado se encontró evidencia de lesiones microscópicas compatibles con procesos de inmunodepresión en órganos del sistema inmune (bursa de Fabricio, timo, bazo y médula ósea) en el 25 % (97) de los casos analizados y se identificaron los genogrupos 1, 2 y 4 en la siguiente proporción: genogrupo 1-69 % (virus clásicos), genogrupo 2-25 % (variantes) y genogrupo 4-6 % (identificado en Suramérica). Estos hallazgos demuestran la presencia de lesiones en órganos del sistema inmune y la existencia de los genogrupos 1, 2 y 3 del IBDV circulando en aves comerciales en Colombia. Esta es la primera investigación en el país con este sistema de clasificación que permite evidenciar con mayor precisión los cambios en el genoma del IBDV. Lo anterior señala la necesidad de continuar con este tipo de estudios para tener una mejor comprensión de la infección en campo y orientar el diseño e implementación de estrategias de control.

ABSTRACT Infectious Bursal Disease Virus (IBDV) is an avibirnavirus with a dsRNA genome, which has a high mutation and recombination rates. Despite the immunosuppressive effect in poultry and the frequency of infections by this agent, few studies in Colombia that characterize the clinical signs and identify the circulating genogroups have been reported. This study aimed to determine the frequency of histopathological lesions in immune organs and to identify IBDV genogroups in poultry from Colombia. In this way, the Laboratorio de Patología Aviar (LPA) databases from the Universidad Nacional de Colombia (period 2016-2018) were analyzed in order to identify the frequency of lesions present in immune organs. 35 samples of the bursa of Fabricius, positive by RT-PCR, were sequenced to the gene that codes for the VP2 protein. 97 (25 %) cases showed microscopic lesions in the immune organs. The genogroups identified and the frequencies were: genogroup 1-69 % (classical viruses), genogroup 2-25 % (antigenic variants), and genogroup 4-6 % (identified in South America). These findings demonstrate the lesions of immune organs and the presence of different genogroups circulating in commercial birds in Colombia. This indicates the need to continue with these studies in order to have a better understanding of the infection in the field and to guide the design and implementation of control strategies.

Detection by PCR of human papillomavirus in Colombia: Comparison of GP5+/6+ and MY09/11 primer sets.

The aims of this study were to determine the prevalence of HPV infection and evaluate the concordance and performance of two primer sets for detecting single and multiple viral infections. A total of 1810 Colombian women were enrolled in the study, and molecular, cytological and epidemiological analyses were performed. Both concordance and performance of two different PCR amplification primer sets (GP5+/6+ and MY09/11) were assessed. The results showed that 60.2% of females with positive HPV DNA were infected by more than one viral type. The OR for multiple infections was 18.2 when using the MY09/11 primer set and 6.52 with the GP5+/6+ primer set. The results also showed an association between GP5+/6+ positivity and the severity of the disease regarding the cytological findings. It was also found that using a single primer set led to underestimating the prevalence for HPV infection. The simultaneous use of these primer sets is an important tool for the detection of HPV DNA, being equally relevant for identifying multiple infections and low viral DNA copies. This study highlights the importance of suitable assessment of HPV epidemiological profiles; screening programs must also be strengthened to broaden the coverage of the most vulnerable populations.

Differentiation of an adult neuron cell line increases susceptibility to rabies infection.

A wide variety of in vitro models have been used for studying rabies infection, however, currently, no central nervous system (CNS) adult neuron cultures are available. The current study determined the susceptibility to rabies infection in an adult CNS neuron cell line (CAD-R1). Cultures of CAD-R1 cells were held for 5 days in medium containing serum (undifferentiated CAD-R1 cells) or in serum-free medium (differentiated CAD-R1 cells). They were then infected with highly neurotropic rabies virus (RV) strain (CVS), obtained from fibroblastic cells (CVS-BHK) or from adult mouse brain (CVS-MB). Undifferentiated and differentiated cells were infected with the two RV strains, but the percentage of infected cells in differentiated cultures was significantly greater (83% and 79%, respectively) than in undifferentiated cells (51% and 60%) (Student's t test<0.05). Susceptibility to infection apparently depended on cellular differentiation state, possibly due to acquisition of additional morphological and biochemical characteristics during the differentiation process that made them more susceptible to RV infection. Therefore, CAD R1 cells may represent a good model for RV infection, making them a useful tool for studying RV neurotropism, infection pathogeny, isolation of street virus or producing safer and most potent vaccines.