Resumen Algunos huéspedes vertebrados tienen la capacidad de contrarrestar las infecciones virales por medio de mecanismos que son entendidos como de resistencia natural. Estos mecanismos hacen parte de la inmunidad innata o de la adquirida y comprenden procesos como apoptosis, interacción virus-receptor, síntesis de moléculas como interferón y óxido nítrico y otros mecanismos como los mediados por el complejo mayor de histocompatibilidad (CMH) o la capacidad de las células asesinas naturales (NK) para reconocer a la célula infectada. En esta revisión vamos a referirnos a los mecanismos de resistencia de los huéspedes a infecciones virales, en los que la apoptosis, el interferón y los receptores celulares juegan un papel protagónico. Palabras clave: factor de necrosis tumoral, proteína mx, proteinkinasa r, 2-5 oligoadenilatosintetasa. Summary Some vertebrate hosts have the capacity to counteract viral infections by means so called mechanisms of natural resistance against viral infections. These mechanisms make part of the innate or acquired immunity and include processes like apoptosis, virus-receptor interactions, synthesis of molecules such as interferon and nitric oxide and other mechanisms mediated by the MHC phenotype or the capacity of natural killer cells to recognize the infected cell. In this review we will discuss host resistance to viral infections through apoptosis, interferon and viral-receptor interactions. Keywords: protein mx, proteinkinase r, tumoral necrosis factor, 2-5 oligoadenilatosintetase.

Resumen El ganado Blanco Orejinegro descendiente del ganado traído por Colón durante su segundo viaje, ha sobrevivido durante casi 500 años en las áreas tropicales colombianas productoras de café. Además de su capacidad adaptativa este ganado ha mostrado otras características como: docilidad, habilidad para aprovechar forrajes de mala calidad, gran habilidad materna, mayor precocidad sexual, alta fertilidad, mayor productividad en cruces F1 (carne y leche) y marcada resistencia a ectoparásitos. Estas características, en conjunto con hallazgos moleculares recientes que sugieren alta variabilidad genética y resistencia a patógenos bacterianos y vírales demuestran que esta raza, que en la actualidad se encuentra en vía de extinción, es portadora de información genética importante que la convierte en una alternativa para la producción en las condiciones tropicales. El objetivo de esta revisión es hacer una recopilación de trabajos realizados con ganado BON; además, mostrar las perspectivas de investigación, basados en los trabajos actualmente llevados a cabo en la Universidad de Antioquia, con el fin de demostrar el potencial genético de esta raza, que quizás no ha podido ser expresado debido a las condiciones de manejo a que esta raza ha sido sometida. Palabras Clave: ganado criollo, Blanco Orejinegro (BON ). Summary BON cattle derived from the domestic animals brought by Christopher Columbus on his second trip have gone through 500 years of adaptation to the tropical coffee producing areas of Colombia. This breed posseses several important characteristics such as: tameness, maternal ability, longevity, high fertility, increased productivity in F1 crosses, and ability to take advantage of rough relatively poor pastures. These qualities together with recent molecular findings suggesting high genetic variability and resistance to viral and bacterial infections make of this breed, now classified as "at risk" of extinction, an invaluable genetic resource from which a national cattle industry adapted to our tropical conditions could be established. The aim of this review it is to compile information about this breed and indicate some research perspectives to the light of advances made at University of Antioquia demonstrating the genetic potential of this breed, that maybe has not been expressed before due to the husbandry conditions to which it has been subjected throughout the five centuries. Key words: Black-ear White cattle, native cattle.

BACKGROUND:The city of Medellin in Colombia has almost no documentation of the causes of acute respiratory infections (ARIs). As part of an ongoing collaboration, we conducted an epidemiologic surveillance for influenza and other respiratory viruses. It described the influenza strains that were circulating in the region along with their distribution over time, and performing molecular characterization to some of those strains. This will contribute to the knowledge of local and national epidemiology. OBJECTIVES:To analyze viral etiologic agents associated with influenza like illness (ILI) in participants reporting to one General hospital in Medelllin, Colombia. RESULTS:From January 2007 to December 2012, a total of 2039 participants were enrolled. Among them, 1120 (54.9%) were male and 1364 (69%) were under the age of five. Only 124 (6%) were older than the age of 15. From all 2039 participants, 1040 samples were diagnosed by either isolation or RT-PCR. One or more respiratory viruses were found in 737 (36%) participants. Of those, 426 (57.8%) got influenza A or B. Adenoviral and parainfluenza infections represented 19.1% and 14.9% of viral infections, respectively. Influenza A was detected almost throughout the whole year except for the first quarter of 2010, right after the 2009 influenza A pandemic. Influenza B was detected in 2008, 2010, and 2012 with no pattern detected. During 2008 and 2010, both types circulated in about the same proportion. Unusually, in many months of 2012, the proportion of influenza B infections was higher than influenza A (ranging between 30% and 42%). The higher proportion of adenovirus was mainly detected in the last quarter of years 2007 and 2010. Adenoviral cases are more frequent in participants under the age of four. CONCLUSIONS:The phylogenetic analysis of influenza viruses shows that only in the case of influenza A/H1N1, the circulating strains totally coincide with the vaccine strains each year.

Background Human rhinoviruses (HRVs) belong to the Picornaviridae family with high similarity to human enteroviruses (HEVs). Limited data is available from Latin America regarding the clinical presentation and strains of these viruses in respiratory disease. Methods We collected nasopharyngeal swabs at clinics located in eight Latin American countries from 3,375 subjects aged 25 years or younger who presented with influenza-like illness. Results Our subjects had a median age of 3 years and a 1.2:1.0 male:female ratio. HRV was identified in 16% and HEV was identified in 3%. HRVs accounted for a higher frequency of isolates in those of younger age, in particular children < 1 years old. HRV-C accounted for 38% of all HRVs detected. Phylogenetic analysis revealed a high proportion of recombinant strains between HRV-A/HRV-C and between HEV-A/HEV-B. In addition, both EV-D68 and EV-A71 were identified. Conclusions In Latin America as in other regions, HRVs and HEVs account for a substantial proportion of respiratory viruses identified in young people with ILI, a finding that provides additional support for the development of pharmaceuticals and vaccines targeting these pathogens.

BackgroundHuman parainfluenza viruses (HPIVs) are common viral causes of community‐acquired pneumonia, particularly in children. The four types of HPIV have world‐wide distribution; however, limited information exists about the epidemiological profile of HPIV in Latin‐America.ObjectiveProvide epidemiologic and phylogenetic information about HPIVs that circulated in Latin America between 2006 and 2010 to better characterize the extent and variability of this respiratory virus in the region.MethodsOropharyngeal swabs, demographic data and clinical characteristics were obtained from individuals with influenza‐like illness in 10 Latin‐American countries between 2006–2010. Specimens were analyzed with culture and molecular methods.ResultsA total of 30 561 individuals were enrolled; 991 (3·2%) were HPIV positive. Most infected participants were male (53·7%) and under 5 years of age (68·7%). The HPIV type most frequently isolated was HPIV‐3 (403, 40·7%). In 66/2007 (3·3%) hospitalized individuals, HPIV was identified. The most frequent symptoms at enrollment were cough and rhinorrhea. We identified certain patterns for HPIV‐1, ‐2 and ‐3 in specific cities. Phylogenetic analysis revealed a homogeneous distribution in the region.ConclusionsIn the current scenario, no vaccine or treatment is available for this pathogen. Our results contribute to the scarce epidemiologic and phylogenetic information of HPIV in the region that could support the development of specific management.

Human metapneumovirus is a newly discovered pathogen associated with respiratory disease and occurring mainly in children. It produces an acute viral respiratory disease picture that varies from mild disease to severe, and which can require strict surveillance in intensive care units. Currently, reverse transcriptase polymerase chain reaction and cell culture are the most common methods for its diagnosis. The first six cases of human metapneumovirus in Colombia are presented from Medellín.

En el Departamento de Microbiologia y Parasitologia, despues de un prolongado analisis que duro por varios anos, nos adelantamos al cambio curricular de la Facultad de Medicina, introduciendo cambios pedagogicos y didacticos en los cursos de Microbiologia y Parasitologia. Las modificaciones mayores fueron: 1. Fusion de los 2 cursos preexistentes en uno solo, sin modificar la intensidad horaira. 2. Disminucion de las clases magistrales. 3. Realizacion de talleres de integracion basico-clinicas. 4. Programacion de paneles dirigidos a la presentacion de visiones diferentes de algunos temas del curso. 5. Propuesta de las tutorias para promover el acercamiento entre profesores y estudiantes. El cambio se inicio en el primer semestre de 1999 y durante 2 semestres se hizo el seguimiento critico y participativo del cual se da cuenta en este informe.

The human metapneumovirus (HMPV) is responsible for acute respiratory tract infections in young children, elderly patients, and immunocompromised hosts. In this study, we genetically analyzed the circulating HMPV in Central and South America from July 2008 to June 2009 and characterized the strains present in this region. Samples were collected during an international collaborative influenza like illness surveillance study and then sequenced with specific primers for the HMPV G gene. Our results show that two distinct clusters of HMPV circulated in Central and South America, subtypes A2 and B2 being the predominant strains.

El metaneumovirus humano es un nuevo patógeno asociado a infecciones respiratorias, principalmente en niños, que produce cuadros clínicos que van desde leves hasta graves, los cuales pueden incluso requerir tratamiento en unidades de cuidados intensivos. Hasta el momento, la reacción en cadena de la polimerasa con transcripción inversa y el cultivo celular son los métodos más usados para su diagnóstico. Se presentan los seis primeros casos de metapneumovirus humano en niños de Medellín, Colombia. doi: http//dx.doi.org/10.7705/biomedica.v32i2.644

Human respiratory syncytial virus (HRSV) is a major cause of viral lower respiratory tract infections among infants and young children. HRSV strains vary genetically and antigenically and have been classified into two broad subgroups, A and B (HRSV-A and HRSV-B, respectively). To date, little is known about the circulating strains of HRSV in Latin America. We have evaluated the genetic diversity of 96 HRSV strains by sequencing a variable region of the G protein gene of isolates collected from 2007 to 2009 in Central and South America. Our results show the presence of the two antigenic subgroups of HRSV during this period with the majority belonging to the genotype HRSV-A2.

BackgroundHuman Adenoviruses are recognized pathogens, causing a broad spectrum of diseases. Serotype identification is critical for epidemiological surveillance, detection of new strains and understanding of HAdvs pathogenesis. Little data is available about HAdvs subtypes in Latin America.MethodsIn this study, we have molecularly characterized 213 adenoviruses collected from ILI presenting patients, during 2006-08, in Central and South America.ResultsOur results indicate that 161(76%) adenoviruses belong to subgroup C, 45 (21%) to subgroup B and 7 (3%) to subtype E4.

Given that highly active antiretroviral therapy (HAART) has been demonstrated useful to restore immune competence in type-1 human immunodeficiency virus (HIV-1)-infected subjects, we evaluated the specific antibody response to influenza vaccine in a cohort of HIV-1-infected children on HAART so as to analyze the quality of this immune response in patients under antiretroviral therapy. Sixteen HIV-1-infected children and 10 HIV-1 seronegative controls were immunized with a commercially available trivalent inactivated influenza vaccine containing the strains A/H1N1, A/H3N2, and B. Serum hemagglutinin inhibition (HI) antibody titers were determined for the three viral strains at the time of vaccination and 1 month later. Immunization induced a significantly increased humoral response against the three influenza virus strains in controls, and only against A/H3N2 in HIV-1-infected children. The comparison of post-vaccination HI titers between HIV-1+ patients and HIV-1 negative controls showed significantly higher HI titers against the three strains in controls. In addition, post vaccination protective HI titers (defined as equal to or higher than 1:40) against the strains A/H3N2 and B were observed in a lower proportion of HIV-1+ children than in controls, while a similar proportion of individuals from each group achieved protective HI titers against the A/H1N1 strain. The CD4+ T cell count, CD4/CD8 T cells ratio, and serum viral load were not affected by influenza virus vaccination when pre- vs post-vaccination values were compared. These findings suggest that despite the fact that HAART is efficient in controlling HIV-1 replication and in increasing CD4+ T cell count in HIV-1-infected children, restoration of immune competence and response to cognate antigens remain incomplete, indicating that additional therapeutic strategies are required to achieve a full reconstitution of immune functions.