Author Institutes (Top 5)
Publications 18

Influenza-like illness (ILI) definitions have been used worldwide for influenza surveillance. These different case definitions can vary with regard to sensitivity and predictive values for laboratory confirmed influenza. The literature has indicated the inclusion of other viruses may be the cause of these variable results. The objective of the study was to evaluate ILI national sentinel criteria and viral etiologies in adults diagnosed with acute respiratory infection (ARI) and/or ILI from 2001 to 2003 in Sao Paulo, Brazil. Clinical and laboratory evaluations were observed from 420 adults and collected on a daily basis from outpatient care units at University Hospital. The ILI definition included: fever plus at least one respiratory symptom (cough and/or sore throat) and one constitutional symptom (headache, malaise, myalgia, sweat or chills, or fatigue). DFA and RT-PCR for influenza, parainfluenza, respiratory syncytial virus, adenovirus, enterovirus, coronavirus, rhinovirus, and metapneumovirus were performed on nasal washes and 61.8% resulted positive. The respiratory viruses detected most often were influenza and rhinovirus. ILI was reported for 240/420 patients (57.1%), with influenza and rhinovirus etiologies accounting for 30.9% and 19.6%, respectively. Rhinovirus peak activity was concurrent with the influenza season. These findings highlight the implications of other viruses in ILI etiology and suggest that during the influenza season, this clinical overlap must be considered in the diagnosis and clinical management of patients.

Avian influenza virus (H5N1) emerged in Hong Kong in 1997, causing severe human disease. In recent years, several outbreaks have been reported in different parts of Asia, Europe and Africa, raising concerns of dissemination of a new and highly lethal influenza pandemic. Although H5N1 has not been capable of sustaining human-to-human transmission, the ability of the virus to undergo variation due to mutations and reassortment, clearly poses the possibility of viral adaptation to the human species. For this reason the World Health Organization has established that we are now in a phase of pandemic alert. Preparing for an influenza pandemic involves a great deal of awareness necessary to stop initial outbreaks, through the use of case recognition, sensitive and rapid diagnostic methods, appropriate therapeutic and preventive measures to reduce spread. Influenza pandemic preparedness involves coordinated pharmacologic and vaccinal strategies, as well as containment measures such as travel restrictions and quarantine approaches.

OBJETIVO: Determinar a prevalência de infecção por rinovírus em lactentes menores de 6 meses hospitalizados por bronquiolite aguda. MÉTODOS: Foram selecionados de forma prospectiva lactentes hospitalizados com diagnóstico de bronquiolite aguda, no Hospital São Lucas da Pontifícia Universidade Católica do Rio Grande do Sul, no período entre maio e setembro de 2002. Foi pesquisada a presença de vírus respiratórios no aspirado nasofaríngeo (ANF), através de imunofluorescência direta para vírus sincicial respiratório, parainfluenza, influenza e adenovírus. Para detecção do rinovírus, foi utilizada a reação de transcrição reversa, seguida de reação em cadeia da polimerase, específicas para picornavírus, seguidas de hibridização com sonda específica para rinovírus. RESULTADOS: Foram selecionados 45 lactentes hospitalizados com diagnóstico de bronquiolite aguda. A mediana da idade dos pacientes selecionados foi de 2 meses. Foram encontradas amostras positivas para vírus respiratórios em 35/45 (77,8%) casos. Foi detectado mais de um vírus em 7/35 (20%) amostras. Das amostras positivas, o vírus sincicial respiratório foi detectado em 33/35 (94%) casos. O rinovírus foi detectado em 6/35 casos (17%). CONCLUSÕES: O rinovírus foi o segundo agente mais freqüentemente detectado em secreção nasal de lactentes jovens hospitalizados por bronquiolite aguda.
OBJECTIVE: To determine the prevalence of rhinovirus infection in hospitalized young infants with acute bronchiolitis. METHODS: Hospitalized children with acute bronchiolitis admitted to the Hospital São Lucas/PUCRS between May and September 2002 were selected prospectively. Nasopharyngeal samples were assayed for respiratory syncytial virus, parainfluenza, influenza and adenovirus by immunofluorescence. For rhinovirus test a reverse transcription-polymerase chain reaction for picornavirus was used, followed by hybridization with rhinovirus specific probes. RESULTS: Forty-five patients were selected for the study. The median age of the subjects studied was 2 months. Positive samples for respiratory viruses were found in 35/45 (77.8%) subjects and 7/35 (20%) patients had dual infection. Respiratory syncytial virus was detected in 33/35 (94%) cases. Rhinovirus was detected in 6/35 patients (17%). CONCLUSIONS: Rhinovirus was the second most common agent detected in nasal secretions from young infants hospitalized with acute bronchiolitis.

Leishmania RNA Virus (LRV, Totiviridae) infect Leishmania cells and subvert mice immune response, probably promoting parasite persistence, suggesting significant roles for LRV in host-parasite interaction. Here we describe a new LRV1-4 purification protocol, enabling capsid visualization by negatively stained electron microscopy representing a significant contribution to future LRV investigations.

Coxsackievirus B5 (CVB5), a human enterovirus of the family Picornaviridae, is a frequent cause of acute and chronic human diseases. The pathogenesis of enteroviral infections is not completely understood, and the fate of the CVB5-infected cell has a pivotal role in this process. We have investigated the CVB5-induced apoptosis of HeLa cells and found that it happens by the intrinsic pathway by a mechanism dependent on the ubiquitin-proteasome system, associated with nuclear aggregation of p53. Striking redistribution of both SUMO and UBC9 was noted at 4 h post-infection, simultaneously with a reduction in the levels of the ubiquitin-ligase HDM2. Taken together, these results suggest that CVB5 infection of HeLa cells elicit the intrinsic pathway of apoptosis by MDM2 degradation and p53 activation, destabilizing protein sumoylation, by a mechanism that is dependent on a functional ubiquitin-proteasome system.

Objective We aimed to assess the profile of respiratory viruses in young children hospitalized for acute lower respiratory tract infection (ALRI) and its association with disease severity, defined as need for pediatric intensive care unit (PICU) admission. Design Prospective observational cohort study. Setting A tertiary-care university hospital in Brazil. Patients Children younger than three years attending the pediatric emergency room with ALRI who were admitted to the hospital. Interventions None. Measurements and main results Nasopharyngeal aspirates were collected from patients from June 1st, 2008 to May 31st, 2009within the first 48 hours of hospitalization. Nasopharyngeal aspirates were tested for 17humanrespiratory viruses by molecular and immunofluorescence based assays. Simple and multiple log-binomial regression models were constructed to assess associations of virus type with a need for PICU admission. Age, prematurity, the presence of an underlying disease and congenital heart disease were covariates. Nasopharyngeal aspirates were positive for at least one virus in 236 patients. Rhinoviruses were detected in 85.6% of samples, with a preponderance of rhinovirus C (RV-C) (61.9%). Respiratory syncytial virus was detected in 59.8% and human coronavirus (HCoV) in 11% of the samples. Co-detections of two to five viruses were found in 78% of the patients. The detection of HCoV alone (adjusted relative risk (RR) 2.18; 95% CI 1.15–4.15) or in co-infection with RV-C (adjusted RR 2.37; 95% CI 1.23–4.58) was independently associated with PICU admission. Conclusions The detection of HCoV alone or in co-infection with RV-C was independently associated with PICU admission in young children hospitalized for ALRI.

Abstract Bats (Order: Chiroptera) harbor a high diversity of emerging pathogens presumably because their ability to fly and social behavior favor the maintenance, evolution, and dissemination of these pathogens. Until 2012, there was only one report of the presence of Hantavirus in bats. Historically, it was thought that these viruses were harbored primarily by rodent and insectivore small mammals. Recently, new species of hantaviruses have been identified in bats from Africa and Asia continents expanding the potential reservoirs and range of these viruses. To assess the potential of Neotropical bats as hosts for hantaviruses and its transmission dynamics in nature, we tested 53 bats for active hantaviral infection from specimens collected in Southeastern Brazil. Part of the hantaviral S segment was amplified from the frugivorous Carollia perspicillata and the common vampire bat Desmodus rotundus. DNA sequencing showed high similarity with the genome of Araraquara orthohantavirus (ARQV), which belongs to one of the more lethal hantavirus clades (Andes orthohantavirus). ARQV-like infection was detected in the blood, urine, and organs of D. rotundus. Therefore, we describe a systemic infection in Neotropical bats by a human pathogenic Hantavirus. We also propose here a schematic transmission dynamics of hantavirus in the study region. Our results give insights to new, under-appreciated questions that need to be addressed in future studies to clarify hantavirus transmission in nature and avoid hantavirus outbreaks.

Respiratory viruses are frequently detected in association with chronic tonsillar hypertrophy in the absence of symptoms of acute respiratory infection (ARI). The present analysis was done in follow-up to a previous clinical study done by this same group. Nasopharyngeal washes (NPWs) were obtained from 83 of 120 individuals at variable times post adenotonsillectomy, in the absence of ARI symptoms. A look back at virus detection results in NPWs from the same 83 individuals at the time of tonsillectomy revealed that 73.5% (61/83) were positive for one or more viruses. The overall frequency of respiratory virus detection in post-tonsillectomy NPWs was 58.8%. Rhinovirus (RV) was the agent most frequently detected, in 38 of 83 subjects (45.8%), followed by enterovirus in 7 (8.4%), human metapneumovirus in 6 (7.2%), human respiratory syncytial virus in 3 (3.6%) and human coronavirus in 1 (1.2%). Remarkably, there was no detection of adenovirus (HAdV) or human bocavirus (HBoV) in asymptomatic individuals in follow-up of adenotonsillectomy. In keeping with persistence of respiratory DNA viruses in human tonsils, tonsillectomy significantly reduces asymptomatic shedding of HAdV and HBoV in NPWs.

Nef is an HIV-1 accessory protein that promotes viral replication and pathogenesis. A key function of Nef is to ensure sustained depletion of CD4 and MHC-I molecules in infected cells by inducing targeting of these proteins to multivesicular bodies (MVBs), and ultimately to lysosomes for degradation. Nef also affects cellular secretory routes promoting its own secretion via exosomes. To better understand the effects of Nef on the exocytic pathway, we investigated whether this viral factor modifies the composition of exosomes released by T lymphocytes. We showed that both CD4 and MHC-I molecules are secreted in exosomes from T cells and that the expression of Nef reduces the amount of these proteins in exosomes. To investigate the functional role for this novel activity of Nef, we performed in vitro HIV-1 infection assays in the presence of distinct populations of exosomes. We demonstrated that exosomes released by CD4+ T cells, but not CD4- T cells, efficiently inhibit HIV-1 infection in vitro. Because CD4 is the main receptor for HIV-1 infection, these results suggest that CD4 molecules displayed on the surface of exosomes can bind to envelope proteins of HIV-1 hindering virus interaction with target cells and infection. Importantly, CD4-depleted exosomes released by CD4+ T cells expressing Nef have a reduced capacity to inhibit HIV-1 infection in vitro. These results provide evidence that Nef promotes HIV-1 infection by reducing the expression of CD4 in exosomes from infected cells, besides the original role of Nef in reducing the CD4 levels at the cell surface.

Oropouche virus (OROV) is an important cause of arboviral illness in Brazil and other Latin American countries, with most cases clinically manifested as acute febrile illness referred to as Oropouche fever, including myalgia, headache, arthralgia and malaise. However, OROV can also affect the central nervous system (CNS) with clinical neurological implications. Little is known regarding OROV pathogenesis, especially how OROV gains access to the CNS. In the present study, neonatal BALB/c mice were inoculated with OROV by the subcutaneous route and the progression of OROV spread into the CNS was evaluated. Immunohistochemistry revealed that OROV infection advances from posterior parts of the brain, including the periaqueductal gray, toward the forebrain. In the early phases of the infection OROV gains access to neural routes, reaching the spinal cord and ascending to the brain through brainstem regions, with little inflammation. Later, as infection progresses, OROV crosses the blood-brain barrier, resulting in more intense spread into the brain parenchyma, with more severe manifestations of encephalitis.

Leishmania RNA Virus (LRV, Totiviridae) infect Leishmania cells and subvert mice immune response, probably promoting parasite persistence, suggesting significant roles for LRV in host-parasite interaction. Here we describe a new LRV1-4 purification protocol, enabling capsid visualization by negatively stained electron microscopy representing a significant contribution to future LRV investigations.

Acute respiratory infections (ARI) are frequent in children and complications can occur in patients with chronic diseases. We evaluated the frequency and impact of ARI and influenza-like illness (ILI) episodes on disease activity, and the immunogenicity and safety of influenza vaccine in a cohort of juvenile idiopathic arthritis (JIA) patients.

Lower respiratory tract infection (LRTI) is a major cause of pediatric morbidity and mortality, especially among non-affluent communities. In this study we determine the impact of respiratory viruses and how viral co-detections/infections can affect clinical LRTI severity in children in a hospital setting.

Chronic tonsillar diseases are an important health problem, leading to large numbers of surgical procedures worldwide. Little is known about pathogenesis of these diseases. In order to investigate the role of respiratory viruses in chronic adenotonsillar diseases, we developed a cross-sectional study to determine the rates of viral detections of common respiratory viruses detected by TaqMan real time PCR (qPCR) in nasopharyngeal secretions, tonsillar tissues and peripheral blood from 121 children with chronic tonsillar diseases, without symptoms of acute respiratory infections. At least one respiratory virus was detected in 97.5% of patients. The viral co-infection rate was 69.5%. The most frequently detected viruses were human adenovirus in 47.1%, human enterovirus in 40.5%, human rhinovirus in 38%, human bocavirus in 29.8%, human metapneumovirus in 17.4% and human respiratory syncytial virus in 15.7%. Results of qPCR varied widely between sample sites: human adenovirus, human bocavirus and human enterovirus were predominantly detected in tissues, while human rhinovirus was more frequently detected in secretions. Rates of virus detection were remarkably high in tonsil tissues: over 85% in adenoids and close to 70% in palatine tonsils. In addition, overall virus detection rates were higher in more hypertrophic than in smaller adenoids (p = 0.05), and in the particular case of human enteroviruses, they were detected more frequently (p = 0.05) in larger palatine tonsils than in smaller ones. While persistence/latency of DNA viruses in tonsillar tissues has been documented, such is not the case of RNA viruses. Respiratory viruses are highly prevalent in adenoids and palatine tonsils of patients with chronic tonsillar diseases, and persistence of these viruses in tonsils may stimulate chronic inflammation and play a role in the pathogenesis of these diseases.

Human bocavirus (HBoV) is a parvovirus recently identified in association with acute respiratory infections (ARI). Despite its worldwide occurrence, little is known on the pathogenesis of HBoV infections. In addition, few systematic studies of HBoV in ARI have been conducted in Latin America. Therefore, in order to test whether active viral replication of human bocavirus is associated with respiratory diseases and to understand the clinical impact of this virus in patients with these diseases, we performed a 3-year retrospective hospital-based study of HBoV in outpatients and inpatients with symptoms of Acute Respiratory Infections (ARI) in Brazil. Nasopharyngeal aspirates (NPAs) from 1015 patients with respiratory symptoms were tested for HBoV DNA by PCR. All samples positive for HBoV were tested by PCR for all other respiratory viruses, had HBoV viral loads determined by quantitative real time PCR and, when possible, were tested by RT-PCR for HBoV VP1 mRNA, as evidence of active viral replication. HBoV was detected in 4.8% of patients, with annual rates of 10.0%, 3.0% and 3.0% in 2005, 2006 and 2007, respectively. The range of respiratory symptoms was similar between HBoV-positive and HBoV-negative ARI patients. However, a higher rate of diarrhea was observed in HBoV-positive patients. High HBoV viral loads (>10⁸ copies/mL) and diarrhea were significantly more frequent in patients with exclusive infection by HBoV and in patients with detection of HBoV VP1 mRNA than in patients with viral co-infection, detected in 72.9% of patients with HBoV. In summary, our data demonstrated that active HBoV replication was detected in a small percentage of patients with ARI and was correlated with concurrent diarrhea and lack of other viral co-infections.

Human respiratory syncytial virus (HRSV) is the major cause of lower respiratory tract infections in children under 5 years of age and the elderly, causing annual disease outbreaks during the fall and winter. Multiple lineages of the HRSVA and HRSVB serotypes co-circulate within a single outbreak and display a strongly temporal pattern of genetic variation, with a replacement of dominant genotypes occurring during consecutive years. In the present study we utilized phylogenetic methods to detect and map sites subject to adaptive evolution in the G protein of HRSVA and HRSVB. A total of 29 and 23 amino acid sites were found to be putatively positively selected in HRSVA and HRSVB, respectively. Several of these sites defined genotypes and lineages within genotypes in both groups, and correlated well with epitopes previously described in group A. Remarkably, 18 of these positively selected tended to revert in time to a previous codon state, producing a "flip-flop" phylogenetic pattern. Such frequent evolutionary reversals in HRSV are indicative of a combination of frequent positive selection, reflecting the changing immune status of the human population, and a limited repertoire of functionally viable amino acids at specific amino acid sites.