Nipah Virus Infection Generates Ordered Structures in Cellulo.

Nipah virus (NiV) is a zoonotic paramyxovirus with a fatality rate of up to 92% in humans. While several pathogenic mechanisms used by NiV to counteract host immune defense responses have been described, all of the processes that take place in cells during infection are not fully characterized. Here, we describe the formation of ordered intracellular structures during NiV infection. We observed that these structures are formed specifically during NiV infection, but not with other viruses from the same Mononegavirales order (namely Ebola virus) or from other orders such as Bunyavirales (Junín virus). We also determined the kinetics of the appearance of these structures and their cellular localization at the cellular periphery. Finally, we confirmed the presence of these NiV-specific ordered structures using structured illumination microscopy (SIM), as well as their localization by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and correlative light and electron microscopy (CLEM). Herein, we describe a cytopathogenic mechanism that provides a new insight into NiV biology. These newly described ordered structures could provide a target for novel antiviral approaches.

Comparative dynamics, morbidity and mortality burden of pediatric viral respiratory infections in an equatorial city.

BACKGROUND: Although acute respiratory infections (ARIs) are the global leading cause of pediatric morbidity and mortality, the relative impact of viral pathogens on pediatric ARIs is still poorly understood, especially in equatorial settings. Long-term studies of multiple viruses concurrently circulating in these regions are still lacking. Here, we report the results of a systematic prospective surveillance of multiple respiratory viruses conducted every weekday for nearly a decade in an equatorial city in Brazil. METHODS: We analyzed the relative burden of influenza, parainfluenza, respiratory syncytial virus (RSV), adenovirus, and metapneumovirus, their seasonality, and their association with climatic and demographic factors, ARI diagnosis, and pediatric mortality. RESULTS AND CONCLUSIONS: RSV was the primary driver of severe childhood respiratory infections, including pneumonia. RSV was also the virus most strongly associated with respiratory-associated deaths, with RSV circulation and pediatric mortality being in phase. Annual circulation of influenza peaked much earlier than annual mortality due to respiratory causes. The results also show that viral circulation can be strongly seasonal even in equatorial regions, which lack seasons with low temperatures: RSV and influenza were concentrated in the rainy season, whereas parainfluenza predominantly circulated in the dry season. The consistent epidemiologic patterns observed can be used for an effective adjustment of the timing of therapeutic and prophylactic interventions in this and potentially in other equatorial regions.

Identification of influenza, parainfluenza, adenovirus and respiratory syncytial virus during rhinopharyngitis in a group of Mexican children with asthma and wheezing.

BACKGROUND: Viral infections can promote allergic sensitization in genetically susceptible individuals. Besides, they are the main cause of wheezing in children. OBJECTIVE: To assess the frequency with which influenza, parainfluenza, adenovirus and respiratory syncytial virus (RSV) cause rhinopharyngitis in patients with asthma and wheezing. PATIENTS AND METHODS: Longitudinal, prospective study in which 168 patients with asthma and wheezing, who attended the outpatient allergy clinic of the National Institute of Pediatrics, Mexico, during the spring (from April through June), with clinical signs and symptoms of rhinopharyngitis were included. Samples of nasal secretions were taken with a long swab, and identification of RSV, adenovirus, infuenza A and B and parainfluenzae 1, 2 and 3 by means of direct immunofluorescence (DI) was carried out. RESULTS: Samples of nasal secretions were taken in 100 children with asthma and 68 with wheezing, aged 2-17 years. Viral identification was positive in 75% and 44.1% of the patients, respectively. By age group, RSV predominated among children in preschool age; and influenza A among children in school age and adolescents. Influenza A, adenovirus and parinfluenza 3 were identified more frequently in asthmatic children, whereas influenza A and RSV in patients with wheezing. Coinfection of two viruses was found in 17.1% of all patients with positive DI; the most frequent association was parainfluenza 1 and 2. CONCLUSIONS: Viral identification by means of DI is a fast and non-invasive technique that could favor the early beginning of antiviral treatments in children with asthma and wheezing.

Parainfluenza virus infection of young children: estimates of the population-based burden of hospitalization.

OBJECTIVE: To determine the population-based inpatient disease burden of parainfluenza virus in children <5 years of age. STUDY DESIGN: The New Vaccine Surveillance Network (NVSN) enrolled children <5 years of age who were hospitalized with febrile or acute respiratory illnesses. Surveillance hospitals admitted >95% of all hospitalized children from each county. Combined nasal turbinate/throat swabs were tested for parainfluenza virus (PIV), respiratory syncytial virus, and influenza virus with culture and reverse-transcription-polymerase chain reaction. Both parental interviews and medical chart reviews were conducted. Age-specific population-based hospitalization rates were calculated. RESULTS: From October 2000 through September 2004, 2798 children were enrolled. A total of 191 PIVs were identified from 189 children (6.8% of enrolled: 73 PIV type 1, 23 PIV type 2, and 95 PIV type 3), compared with 521 respiratory syncytial viruses and 159 influenza viruses. Mean PIV hospitalization rates were 3.01, 1.73, 1.53, 0.39, and 1.02 per 1000 children per year for ages 0 to 5 months, 6 to 11 months, 12 to 23 months, 24 to 59 months, and 0 to 59 months, respectively. CONCLUSIONS: PIV accounted for 6.8% of all hospitalizations for fever, acute respiratory illnesses, or both in children <5 years of age. The pediatric PIV inpatient burden is substantial and highlights the need to find an effective vaccine candidate.