Seminars in respiratory and critical care medicine
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Semin Respir Crit Care Med · Aug 2011
ReviewInfluenza: epidemiology, clinical features, therapy, and prevention.
Influenza A and B are important causes of respiratory illness in all age groups. Influenza causes seasonal outbreaks globally and, less commonly, pandemics. In the United States, seasonal influenza epidemics account for >200,000 hospitalizations and >30,000 deaths annually. ⋯ Vaccines are the cornerstone of influenza control. Currently, trivalent inactivated vaccine (TIV) and live attenuated influenza vaccine (LAIV) are available. These agents reduce mortality and morbidity in high-risk patients (i.e., the elderly or patients with comorbidities), and expanding the use of vaccines to healthy children and adults reduces the incidence of influenza, pneumonia, and hospitalizations due to respiratory illnesses in the community.
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Adenoviruses (AdV) are DNA viruses that typically cause mild infections involving the upper or lower respiratory tract, gastrointestinal (GI) tract, or conjunctiva. Rare manifestations of AdV infections include hemorrhagic cystitis, hepatitis, hemorrhagic colitis, pancreatitis, nephritis, or encephalitis. Adenovirus infections are more common in young children, owing to lack of humoral immunity. ⋯ Treatment of AdV infections is controversial because prospective, randomized therapeutic trials have not been done. Cidofovir is considered the drug of choice for severe AdV infections, but not all patients require treatment. Vaccines have been shown to be highly efficacious in reducing the risk of respiratory AdV infection but are currently not available.
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Semin Respir Crit Care Med · Aug 2011
ReviewPandemic novel 2009 H1N1 influenza: what have we learned?
In March 2009, cases of influenza-like illness in Mexico caused by a novel H1N1 virus containing genes from swine, avian, and human influenza strains were reported. Within several weeks, 2009 H1N1 disseminated rapidly and was the predominant influenza strain globally. On June 11, 2009, the World Health Organization declared that criteria for an influenza pandemic had been met. ⋯ Because most infected individuals have mild, self-limited disease, the risk/benefit assessment for early access to antiviral agents must balance the potential benefit for reducing transmission, disease severity, and burden on health care providers against the potential for dissemination of viral resistance and drug-related adverse events. Monovalent vaccines against 2009 H1N1 were developed and ready for distribution by September 2009, but initial supplies were inadequate to impact the bulk of cases that occurred in the Northern Hemisphere between April and September 2009. Continued efforts to develop universal vaccines and improve access to effective vaccines are critical.
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Rhinoviruses and coronaviruses cause significant morbidity in immunocompetent people of all ages and in patients with underlying chronic medical or immunosuppressed conditions. Newer diagnostic tests, such as polymerase chain reaction (PCR), have expanded our understanding of these respiratory viruses in clinical infections. These sensitive diagnostic tests have been used to describe new members of these virus families, such as human rhinovirus C (HRVC) and human coronavirus NL-63 (HCoV-NL63). The epidemiology of these newly described viruses will help us develop better intervention strategies.
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Semin Respir Crit Care Med · Aug 2011
ReviewMolecular assays for the detection and characterization of respiratory viruses.
Patient care providers face an enormous challenge in diagnosing vial respiratory diseases because of similar clinical manifestations, as well as insensitivity and/or slow conventional laboratory detection methods. Nucleic acid-targeted molecular assays are playing critical roles in rapid detection, screening, and identification of respiratory viral pathogens due to their high sensitivity and specificity, short test turnaround time, as well as automatic and high-throughput processing. ⋯ Incorporated with cutting edge techniques, these methods can be used to detect one or more pathogens in a single reaction tube qualitatively and quantitatively. Although the molecular assays have been increasingly used in the clinical setting, laboratorians and clinicians should well know the limitations of these molecular assays to wisely choose the right tests and correctly interpret test results.