Sentinel surveillance of influenza-like illness in two hospitals in Maracay, Venezuela: 2006-2010.

BACKGROUND: Limited information exists on the epidemiology of acute febrile respiratory illnesses in tropical South American countries such as Venezuela. The objective of the present study was to examine the epidemiology of influenza-like illness (ILI) in two hospitals in Maracay, Venezuela. METHODOLOGY/PRINCIPAL FINDINGS: We performed a prospective surveillance study of persons with ILI who presented for care at two hospitals in Maracay, Venezuela, from October 2006 to December 2010. A respiratory specimen and clinical information were obtained from each participant. Viral isolation and identification with immunofluorescent antibodies and molecular methods were employed to detect respiratory viruses such as adenovirus, influenza A and B, parainfluenza, and respiratory sincytial virus, among others. There were 916 participants in the study (median age: 17 years; range: 1 month--86 years). Viruses were identified in 143 (15.6%) subjects, and one participant was found to have a co-infection with more than one virus. Influenza viruses, including pandemic H1N1 2009, were the most frequently detected pathogens, accounting for 67.4% (97/144) of the viruses detected. Adenovirus (15/144), parainfluenza virus (13/144), and respiratory syncytial virus (11/144) were also important causes of ILI in this study. Pandemic H1N1 2009 virus became the most commonly isolated influenza virus during its initial appearance in 2009. Two waves of the pandemic were observed: the first which peaked in August 2009 and the second--higher than the preceding - that peaked in October 2009. In 2010, influenza A/H3N2 re-emerged as the most predominant respiratory virus detected. CONCLUSIONS/SIGNIFICANCE: Influenza viruses were the most commonly detected viral organisms among patients with acute febrile respiratory illnesses presenting at two hospitals in Maracay, Venezuela. Pandemic H1N1 2009 influenza virus did not completely replace other circulating influenza viruses during its initial appearance in 2009. Seasonal influenza A/H3N2 was the most common influenza virus in the post-pandemic phase.

Population structure of the dengue viruses, Aragua, Venezuela, 2006-2007. Insights into dengue evolution under hyperendemic transmission.

During the past three decades there has been a notable increase in dengue disease severity in Venezuela. Nevertheless, the population structure of the viruses being transmitted in this country is not well understood. Here, we present a molecular epidemiological study on dengue viruses (DENV) circulating in Aragua State, Venezuela during 2006-2007. Twenty-one DENV full-length genomes representing all of the four serotypes were amplified and sequenced directly from the serum samples. Notably, only DENV-2 was associated with severe disease. Phylogenetic trees constructed using Bayesian methods indicated that only one genotype was circulating for each serotype. However, extensive viral genetic diversity was found in DENV isolated from the same area during the same period, indicating significant in situ evolution since the introduction of these genotypes. Collectively, the results suggest that the non-structural (NS) proteins may play an important role in DENV evolution, particularly NS1, NS2A and NS4B proteins. The phylogenetic data provide evidence to suggest that multiple introductions of DENV have occurred from the Latin American region into Venezuela and vice versa. The implications of the significant viral genetic diversity generated during hyperendemic transmission, particularly in NS protein are discussed and considered in the context of future development and use of human monoclonal antibodies as antivirals and tetravalent vaccines.

Multicentre prospective study on dengue classification in four South-east Asian and three Latin American countries.

OBJECTIVE: To evaluate the existing WHO dengue classification across all age groups and a wide geographical range and to develop a revised evidence-based classification that would better reflect clinical severity. METHODS: We followed suspected dengue cases daily in seven countries across South-east Asia and Latin America and then categorised them into one of three intervention groups describing disease severity according to the overall level of medical and nursing support required. Using a pre-defined analysis plan, we explored the clinical and laboratory profiles characteristic of these intervention categories and presented the most promising options for a revised classification scheme to an independent group of WHO dengue experts for consideration. Potential warning signs were also evaluated by comparing contemporaneous data of patients who progressed to severe disease with the data of those who did not. RESULTS: A total of 2259 patients were recruited during 2006-2007 and 230 (13%) of the 1734 laboratory-confirmed patients required major intervention. Applying the existing WHO system, 47/210 (22%) of patients with shock did not fulfil all the criteria for dengue haemorrhagic fever. However, no three-tier revision adequately described the different severity groups either. Inclusion of readily discernible complications (shock/severe vascular leakage and/or severe bleeding and/or severe organ dysfunction) was necessary to devise a system that identified patients requiring major intervention with sufficient sensitivity and specificity to be practically useful. Only a small number of subjects (5%) progressed to severe disease while under observation; several warning signs were identified, but much larger studies are necessary to fully characterize features associated with disease progression. CONCLUSIONS: Based on these results, a revised classification system comprised of two entities, 'Dengue' and 'Severe Dengue', was proposed and has now been incorporated into the new WHO guidelines.

Multi-country evaluation of the sensitivity and specificity of two commercially-available NS1 ELISA assays for dengue diagnosis.

BACKGROUND: Early diagnosis of dengue can assist patient triage and management and prevent unnecessary treatments and interventions. Commercially available assays that detect the dengue virus protein NS1 in the plasma/serum of patients offers the possibility of early and rapid diagnosis. METHODOLOGY/PRINCIPAL FINDINGS: The sensitivity and specificity of the Pan-E Dengue Early ELISA and the Platelia Dengue NS1 Ag assays were compared against a reference diagnosis in 1385 patients in 6 countries in Asia and the Americas. Platelia was more sensitive (66%) than Pan-E (52%) in confirmed dengue cases. Sensitivity varied by geographic region, with both assays generally being more sensitive in patients from SE Asia than the Americas. Both kits were more sensitive for specimens collected within the first few days of illness onset relative to later time points. Pan-E and Platelia were both 100% specific in febrile patients without evidence of acute dengue. In patients with other confirmed diagnoses and healthy blood donors, Platelia was more specific (100%) than Pan-E (90%). For Platelia, when either the NS1 test or the IgM test on the acute sample was positive, the sensitivity versus the reference result was 82% in samples collected in the first four days of fever. NS1 sensitivity was not associated to disease severity (DF or DHF) in the Platelia test, whereas a trend for higher sensitivity in DHF cases was seen in the Pan-E test (however combined with lower overall sensitivity). CONCLUSIONS/SIGNIFICANCE: Collectively, this multi-country study suggests that the best performing NS1 assay (Platelia) had moderate sensitivity (median 64%, range 34-76%) and high specificity (100%) for the diagnosis of dengue. The poor sensitivity of the evaluated assays in some geographical regions suggests further assessments are needed. The combination of NS1 and IgM detection in samples collected in the first few days of fever increased the overall dengue diagnostic sensitivity.

Caracterización epidemiológica de los pacientes infectados por virus de hepatitis C en el estado Aragua, 2002-2007. Comité de hepatitis del estado Aragua

Venezuela presenta un subregistro de infección por VHC. Hay una prevalencia de 1,2%, demostrada en estudios aislados, 2,5% en una serie realizada en población pediátrica y 1,92% en trabajadores de salud. Se desconoce la prevalencia y características epidemiológicas de VHC en el estado Aragua. Se presenta la experiencia de 5 años del Comité de Hepatitis del Estado Aragua (CHA). Objetivos: Caracterizar epidemiológicamente la población infectada por VHC en el Estado Aragua, tomando en cuenta género, edad, estado civil, actividad laboral, antecedente de exposición ocupacional, cirugías previas, transfusiones sanguíneas, hemoderivados, procedencia, genotipo predominante, coinfección por VHB, VIH, VEB, Parvovirus B-19. Materiales y métodos: Encuesta epidemiológica a 101 pacientes con diagnóstico serológico de VHC; rango de edad, 18 - 80 años. Resultados: 60% género masculino, edad promedio 43 años ambos géneros (31,3%), 67,7% casados, provenientes en mayor porcentaje del Municipio Girardot(27,4%). En su mayoría sin profesión definida (80,2%), predominando comerciantes y obreros. De los trabajadores del sector salud (8%), 42% con antecedente de exposición ocupacional. 81,1% asintomáticos en el momento del diagnóstico y 31,8% presentó síntomas inespecíficos. 60,2% refirió cirugías previas; 29,8% transfusiones sanguíneas y, en este grupo, 49% las recibió antes de 1992. Genotipo 1 fue predominante (33,3%); sólo 8% de la población presentó coinfección por VHB, VIH, VEB o Parvovirus B-19. Conclusiones: Predominó el genero masculino, edad promedio 43 años, casados, no profesionales, 60,2% refirió cirugías previas y, en menor porcentaje (29,8%), transfusiones sanguíneas, predominó genotipo 1 y en su mayoría fueron asintomáticos.

Venezuela presents a sub-record of the HCV infection. There is a prevalence of this infection of 1.2%, demonstrated in isolated studies, 2.5 % in a set made in a pediatric population, and 1.92 % in health care workers. The prevalence and epidemiologic characteristics of the HCV infection in the Aragua State are unknown. Here, it is reported the experience of the Hepatitis Committee in the Aragua State for 5 years. Objetives: Carry out the epidemiologic characterization of the HCV infected population of the Aragua State, regarding gender, age, civil status, address, job, history of occupational exposure, previous surgeries, blood transfusion, genotype of the virus, and coinfection with HBV, HIV, EBV or Parvovirus B-19. Materials and methods: Epidemiologic interview applied to 101 patients with serologic diagnosis of HCV, between 18 and 80 years old. Results: The 60 % of infected patients were males, the average age to both genders was of 43 years old (31.3 %), 67.7 % were married, mainly from the Giradot District (27.4 %). Most of this infected patients didnÊt have a specific profession (80.2 %), and consisted predominantly of traders and workers. Of the health care professionals (8 %), 42 % had history of occupational exposition. The 81.1 % of infected patients were asymptomatic at the time of the diagnosis, and 31.8 % showed unspecific symptoms. The 60.2 % had been previously subjected to surgery; 29.8 % to blood transfusion, and 49 % of the patients in this group received the transfusion before 1992. The virus genotype 1 was the predominant (33.3 %); and only 8 % of the infected population studied had coinfection with HBV, HIV,Parvovirus B-19 or EBV. Conclusions: in the infected population studied prevailed the male gender, an average age of 43 years old, the married condition, non professionals, 60.2 % reported a previous surgery, and a lower porcentage (29,8%), blood transfusions most of them were infected with genotype 1 virus and were asymptomatic.

[Use of polymerase chain reaction for the diagnosis of central nervous system infections]. / Utilización de la reacción en cadena de la polimerasa para el diagnóstico de infecciones del sistema nervioso central.

In the present work, the polymerase chain reaction (PCR) assay and his variants RT-PCR and Multiplex PCR were applied for the detection of specific sequences of Enterovirus, Human Herpes viruses (Herpes simple virus, Human Herpes virus type 6, Cytomegalovirus, Epstein Barr virus, and Varicella Zoster), Human Immunodeficiency virus, Toxoplasma gondii, Mycobacterium tuberculosis and Mycoplasma pneumoniae in patients' cohorts grouped by medical suspicion of meningoencephalitis. Of 326 samples of processed cerebrospinal fluid (CSF), 93 samples (28.5%) were positive for the different infectious agents. In the group of patients with clinical diagnosis of viral meningoencephalitis (n=212), there was obtained a whole of 73 positive samples (34.4%), of which 37 patients were positive to Enterovirus (50.7%), 19 were positive to VHS (26%) and 10 patients (13.7%) were positive to CMV. Other viral agents as VZV, EBV and HVH6 were detected in minor frequency. The 114 remaining samples were analyzed applying specific PCR to each pathogen for strict medical indication, being able to detect the presence of Human Immunodeficiency Virus (40%), Mycoplasma pneumoniae (40%), Toxoplasma gondii (14%) and Mycobacterium tuberculosis (12%) in CSF samples. The results obtained in this study demonstrate the convenience of the application of the molecular assays in the laboratory diagnosis of the meningoencefalitis of different etiology. Besides this, it is also a very valuable tool for the clinical management of the patients and for the execution of the epidemiological studies.

Utilización de la reacción en cadena de la Polimerasa para el diagnóstico de infecciones del sistema nervioso central / Use of Polymerase chain reaction for the diagnosis of central nervous system infections

En el presente trabajo se aplicó el ensayo de Reacción en Cadena de la Polimerasa (PCR) y sus variantes RT-PCR y Multiplex PCR para la detección de secuencias específicas de Enterovirus, Herpesvirus humanos (Virus Herpes simple y Virus Herpes tipo 6, Citomegalovirus, Epstein Barr, Varicela Zoster), Virus de Inmunodeficiencia Humana, Toxoplasma gondii, Micobacterium tuberculosis y Micoplasma pneumoniae en muestras de liquido cefalorraquídeo (LCR) de cohortes de pacientes con sospecha clínica de meningoencefalitis. De las 322 muestras de LCR procesadas, se detectaron un total de 93 muestras positivas (28,8 por ciento) para los distintos agentes infecciosos. En el grupo de pacientes con diagnóstico clínico de meningoencefalitis viral (n=212), se obtuvo un total de 73 muestras positivas (34,4 por ciento), de las cuales 37 fueron positivas a Enterovirus (50,7 por ciento), 19 a VHS (26 por ciento) y 10 pacientes (13,7 por ciento) fueron positivos a CMV. Los otros agentes virales VZV, EBV y HVH6 se encontraron en menor frecuencia. Las 110 muestras restantes de LCR se analizaron aplicando PCR específicos a cada patógeno por estricta indicación médica, pudiéndose detectar en ellas la presencia de Virus de lnmunodeficiencia Humana (40 por ciento), Micoplasma pneumoniae (40 por ciento), Toxoplasma gondii (14 por ciento) y Micobacterium tuberculosis (12 por ciento). Los resultados obtenidos en este estudio demuestran la conveniencia de la aplicación de las técnicas moleculares en el diagnóstico de laboratorio de las meningoencefalitis de diferente etiología, siendo además una herramienta muy valiosa para el manejo clínico de los pacientes y para la ejecución de estudios epidemiológicos

Estratificacion de una ciudad hiperendemica en dengue hemorragico / Stratification of a city with hyperendemic dengue hemorrhagic fever

La gran heterogeneidad ambiental de viviendas y barrios en los centros urbanos donde se cria Aedes aegypti, principal vector del dengue, junto con la escasez de recursos y de personal entrenado en el control de mosquitos constituyen retos para cualquier iniciativa destinada a controlar el dengue hemorragico (DH). Una adecuada vigilancia epidemiologica puede servir de base para comenzar a estratificar los centros urbanos e identificar las zonas criticas donde deben concentrarse las tareas de control. En este estudio, se estratifico una ciudad hiperendemica en dengue hemorragico (Maracay, Venezuela) con la ayuda de un sistema de informacion geografica (SIG) y el analisis de la persistencia, la incidencia y la prevalencia del dengue mediante diagnosticos clinicos registrados de 1993 a 1998. Maracay tiene cerca de un millon de habitantes que viven en unos 349 barrios de 6 poblaciones que integran el Area Metropolitana, donde se notificaron 10.576 casos de dengue, 2.593 casos de DH y 8 defunciones. La incidencia de DH mostro una relacion directa con la incidencia del dengue, el numero de habitantes y la densidad poblacional. El patron espacial de la incidencia del dengue fue estable durante los anos estudiados y se encontraron relaciones positivas y significativas de la incidencia del dengue por barrio entre pares de anos. La persistencia del dengue se relaciono directamente con la incidencia mensual por barrio. Estos patrones espaciales facilitaron la estratificacion de la ciudad en tres estratos: 68 barrios sin dengue aparente, 226 barrios con baja persistencia y prevalencia, y 55 barrios con alta persistencia y prevalencia. Se recomienda otorgar alta prioridad de control a estos 55 barrios que ocupan 35 por ciento del area urbana y presentaron 70 por ciento de todos los casos de dengue