Viral antigens and nucleic acids may be focal and sparsely distributed in patients with influenza. Larger airways (particularly primary and segmental bronchi) have the highest yield for detection of influenza viruses by IHC staining. In comparison, viral RNA is more commonly detected in lower airways. Collection of the appropriate tissues ensures the best chance of detecting the virus by immunohistochemical stains and PCR tests.
Pregnant women with H1N1 influenza would be expected to present with typical acute respiratory illness (e.g., cough, sore throat, rhinorrhea) and fever or feverishness. Many pregnant women will go on to have a typical course of uncomplicated influenza. However, for some pregnant women, illness might progress rapidly, and might be complicated by secondary bacterial infections including pneumonia.
On April 24, 2009, CDC reported eight confirmed cases of swine-origin influenza A (H1N1) virus (S-OIV) infection in Texas and California. The strain identified in U.S. patients was confirmed by CDC as genetically similar to viruses subsequently isolated from patients in Mexico.
Provides interim guidance on appropriate specimen collection, storage, and processing for patients with suspected swine influenza A (H1N1) virus infection.
Human infections with a swine-origin influenza A (H1N1) virus that is transmissible among humans were first identified in April 2009 with cases in the United States and Mexico. The epidemiology and clinical presentations of these infections are currently under investigation. There are insufficient data available at this point to determine who is at higher risk for complications of swine-origin influenza A (H1N1) virus infection. However, adults and adolescents with HIV infection, especially persons with low CD4 cell counts, are known to be at higher risk for viral and bacterial lower respiratory tract infections and for recurrent pneumonias.
This document provides interim guidance for state and local health departments conducting investigations of human cases of swine-origin influenza A (H1N1) virus (S-OIV). The following case definitions are for the purpose of investigations of suspected, probable, and confirmed cases of S-OIV infection.
CDC reports additional confirmed human infections, hospitalizations and the nation's first fatality from this outbreak. Recent illnesses and the reported death suggest that a pattern of more severe illness associated with this virus may be emerging in the U.S.
This document provides interim guidance for clinicians who might provide care for patients with swine-origin influenza A (H1N1) or suspected swine-origin influenza A (H1N1) virus infection. It will be periodically updated as information becomes available.
This document provides interim guidance for healthcare facilities (e.g., hospitals, long-term care and outpatient facilities, and other settings where healthcare is provided) and will be updated as needed.
This document provides interim guidance for 9-1-1 Public Safety Answering Points (PSAPs), the Emergency Medical Services (EMS) system and medical first-responders.