Seminars in respiratory and critical care medicine
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Semin Respir Crit Care Med · Apr 2007
ReviewCommunity respiratory virus infections in immunocompromised patients: hematopoietic stem cell and solid organ transplant recipients, and individuals with human immunodeficiency virus infection.
Infection is the leading cause of morbidity and mortality in immunocompromised patients such as hematopoietic/solid organ transplant recipients and individuals with human immunodeficiency virus. Community respiratory virus infections are increasingly recognized as a significant threat to these patients. This article reviews current information in the clinical field of community respiratory viruses, including several newly discovered respiratory viruses. ⋯ The clinical impact of these new viruses, including human metapneumovirus, non-SARS human coronaviruses, and human bocavirus, is not yet clear. Modern molecular technology has made the discovery of new viruses possible; the use of these new technologies in direct patient care is not yet standard but is becoming increasingly utilized. Clinicians should appreciate the potential for the development of antiviral resistance to influenza antivirals in immunocompromised patients.
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Viral respiratory infections continue to cause significant morbidity and mortality in infants and young children as well as in at-risk adults and the elderly. Although many viral pathogens are capable of causing acute respiratory disease, vaccine development has to focus on a limited number of pathogens (i.e., agents that commonly cause serious lower respiratory disease). Inactivated and, more recently, live attenuated influenza virus vaccines are the mainstay of interpandemic influenza prevention, but vaccines are not available yet for other important viruses such as respiratory syncytial virus, metapneumovirus, the parainfluenza viruses, and avian influenza viruses with pandemic potential. Reverse genetics systems that allow rational vaccine development are now widely used, and considerable progress has been made in preclinical and clinical development of novel respiratory virus vaccines.
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Hantavirus cardiopulmonary syndrome (HCPS) is caused by infection with multiple types of hantaviruses throughout the Americas. All strains induce a pulmonary capillary leak syndrome with cardiogenic shock in severe cases, and almost all strains have an overall mortality rate of 35%. Some strains in South America are commonly associated with either mild disease without pulmonary edema or severe disease with pulmonary hemorrhage. ⋯ Limited fluid replacement, early inotropic therapy, and mechanical ventilation also improve survival. Extracorporeal membrane oxygenation (ECMO) has been life saving for patients with refractory shock. Ribavirin does not appear to reduce mortality, but hyperimmune serum offers a promising future therapy because survival is correlated with higher neutralizing antibody titers at admission.
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Rhinoviruses and coronaviruses cause the majority of common colds and play a part in more serious respiratory illnesses that lead to increased morbidity and mortality. Patients who are infants or elderly, have asthma or chronic obstructive pulmonary disease (COPD), or are immunosuppressed have increased frequency of rhinovirus-related respiratory complications. Newer diagnostic tests such as reverse transcriptase polymerase chain reaction (RT-PCR) have greatly expanded our understanding of the importance of these respiratory viruses. Although there are no currently approved antiviral agents for clinical use, our increased understanding of the virus-host interaction should lead to new intervention strategies.
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Semin Respir Crit Care Med · Apr 2007
ReviewInfluenza: evolving strategies in treatment and prevention.
Influenza A and B are important causes of respiratory illness in all age groups. Influenza causes seasonal outbreaks globally, and (rarely) 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.