Viremia en plasma como factor asociado a gravedad en la infección por el virus del dengue: revisión sistemática de la literatura / Plasma viraemia as a factor associated to severity in dengue virus infection: systematic review of literature

Resumen Introducción: La viremia plasmática es un factor cuyo rol en la gravedad de la infección por el virus del dengue se ha discutido ampliamente en los últimos años, siendo hallados resultados divergentes en los múltiples contextos evaluados. Métodos: Se realizó una revisión sistemática de la literatura utilizando las bases de datos Scopus, EBSCOhost, SpringerLink, Lilacs y Scielo. Se consideraron para su inclusión en la revisión estudios que evaluaran la relación entre la carga viral en plasma y las manifestaciones clínicas o la gravedad de la enfermedad. Resultados: Se obtuvieron 80 referencias en la búsqueda inicial, posterior a la aplicación de los criterios de inclusión/exclusión fueron seleccionados 20 artículos. En el estudio de este fenómeno son múltiples los parámetros desde los cuales debe ser evaluada la viremia, no sólo desde su magnitud, sino también desde su duración post-defervescencia y el día en el que se reporta el valor máximo, entre otros. Discusión: Los resultados de los estudios indican que las características de la viremia pueden jugar un rol de importancia que, junto con otros factores del contexto viral (serotipo del virus, tipo de infección) y del paciente (edad, genotipo, comorbilidades, etc), pueden determinar el desenlace clínico de la infección.

Background: Plasma viremia is a factor whose role in the severity of dengue virus infection has been widely discussed in recent years, with divergent results found in the multiple contexts evaluated. Methods: A systematic review of the literature using the Scopus, EBSCOhost, SpringerLink, Lilacs and Scielo databases was conducted. For inclusion in the review there were considered studies that evaluated the relationship between plasma viral load and clinical manifestations or severity of the disease. Results: We obtained 80 references in the initial search, after the application of the inclusion / exclusion criteria 20 articles were selected. In the study of this phenomenon there are multiple parameters from which viremia should be evaluated, not only from its magnitude, but also from the post-defervescence duration and the day in which the maximum value is reported, among others. Discussion: The results of the studies indicate that the characteristics of viremia may play an important role that, along with other factors of the viral (virus serotype, type of infection) and patient context (age, genotype, comorbidities, etc.), determine the clinical outcome of the infection.

Genetic analysis of ORF5 of recent Korean porcine reproductive and respiratory syndrome viruses (PRRSVs) in viremic sera collected from MLV-vaccinating or non-vaccinating farms

The 23 open reading frame (ORF) 5 sequences of Korean type II porcine reproductive and respiratory syndrome virus (PRRSV) were collected from viremic sera from the (modified live vaccine) MLV-vaccinating and non-vaccinating farms from 2007 to 2008. The samples were phylogenetically analyzed with previous ORF5 sequences, including type I Korean PRRSV, and previously reported or collected sequences from 1997 to 2008. A MN184-like subgroup of type II Korean PRRSV was newly identified in the viremic sera collected from 2007 to 2008. And of the type I PRRSVs, one subgroup had 87.2~88.9% similarity with the Lelystad virus, showing a close relationship with the 27~2003 strain of Spain. The maximum parsimony tree of type II PRRSV from 1997 to 2008 showed that they had evolved to four lineages, subgroups 1, 2, 3 and 4. Most of the recently collected type II PRRSVs belonged to subgroup 4 (48%). The region of three B-cell epitopes and two T-cell epitopes of ORF5 amino acids sequences was considerably different from the MLV in subgroups 3 and 4. In conclusion, the existence of type I PRRSV, which was genetically different from Lelystad virus (Prototype of type I PRRSV), and heterologous type II PRRSVs of viremic pigs detected even in the MLV-vaccinating farms indicated the need for new vaccine approaches for the control of PRRSV in Korea.

Hepatitis G virus infection in hemodialysis and continuous ambulatory peritoneal dialysis patients

To determine the prevalence and clinical relevance of HGV infection in dialysis patients, we performed a cross-sectional study of 61 HD patients and 79 Continuous Ambulatory Peritoneal Dialysis (CAPD) patients. HGV-RNA was identified by reverse-transcription (RT) polymerase chain reaction (PCR) assay with primers from the 5'-untranslated region of the viral genome. The prevalence of HGV infection was similar in HD and CAPD patients (9.8% vs. 12.7%), while that of HCV infection was significantly higher in HD patients compared to CAPD patients (16.4% vs. 1.3%, p < 0.05). The mean age (49.2 +/- 13.4 vs. 46.7 +/- 13.0 years), male to female ratio (2.4:1 vs. 1.3:1), history of transfusion (62.3% vs. 49.4%), history of hepatitis (27.9% vs. 26.6%), mean ALT level during the previous 6 months (22.4 +/- 37.9 vs. 14.0 +/- 7.4 IU/L), and the prevalence of HBsAg (8.2% vs. 6.3%) showed no difference between HD and CAPD patients. In both HD and CAPD patients, the presence of HGV RNA was not related to age, sex, duration of dialysis, history of transfusion, history of hepatitis, or to the presence of HBV or HCV markers. There was no significant difference in the clinical and biochemical data between patients with isolated HGV infection (n = 12) and patients without viremia (n = 106). The clinical feature of patients coinfected with HGV and HBV (n = 2), or HGV and HCV (n = 2) seemed to be similar to those of patients with isolated HBV (n = 8) or HCV (n = 9) infection. In conclusion, the prevalence of HGV infection was not different between HD and CAPD patients, and HGV infections did not seem to be associated with clinically significant hepatitis. The routes of HGV transmission, other than transfusion or contamination during HD procedure, were suspected.