Outbreak of antiviral drug-resistant influenza a in long-term care facility, Illinois, USA, 2008.

An outbreak of oseltamivir-resistant influenza A (H1N1) occurred in a long-term care facility. Eight (47%) of 17 and 1 (6%) of 16 residents in 2 wards had oseltamivir-resistant influenza A virus (H1N1) infections. Initial outbreak response included treatment and prophylaxis with oseltamivir.

Pyrosequencing as a tool to detect molecular markers of resistance to neuraminidase inhibitors in seasonal influenza A viruses.

Pyrosequencing has been successfully used to monitor resistance in influenza A viruses to the first class of anti-influenza drugs, M2 blockers (adamantanes). In contrast to M2 blockers, resistance to neuraminidase (NA) inhibitors (NAIs) is subtype- and drug-specific. Here, we designed a pyrosequencing assay for detection of the most commonly reported mutations associated with resistance to NAIs, a newer class of anti-influenza drugs.

Surveillance for neuraminidase inhibitor resistance among human influenza A and B viruses circulating worldwide from 2004 to 2008.

The surveillance of seasonal influenza virus susceptibility to neuraminidase (NA) inhibitors was conducted using an NA inhibition assay. The 50% inhibitory concentration values (IC(50)s) of 4,570 viruses collected globally from October 2004 to March 2008 were determined. Based on mean IC(50)s, A(H3N2) viruses (0.

No evidence of avian influenza A (H5N1) among returning US travelers.

We reviewed reports to the Centers for Disease Control and Prevention of US travelers suspected of having avian influenza A (H5N1) virus infection from February 2003 through May 2006. Among the 59 reported patients, no evidence of H5N1 virus infection was found; none had direct contact with poultry, but 42% had evidence of human influenza A.

Influenza-associated deaths among children in the United States, 2003-2004.

Background: Although influenza is common among children, pediatric mortality related to laboratory-confirmed influenza has not been assessed nationally.

Methods: During the 2003-2004 influenza season, we requested that state health departments report any death associated with laboratory-confirmed influenza in a U.S.

Incidence of adamantane resistance among influenza A (H3N2) viruses isolated worldwide from 1994 to 2005: a cause for concern.

Background: Adamantanes have been used to treat influenza A virus infections for many years. Studies have shown a low incidence of resistance to these drugs among circulating influenza viruses; however, their use is rising worldwide and drug resistance has been reported among influenza A (H5N1) viruses isolated from poultry and human beings in Asia. We sought to assess adamantane resistance among influenza A viruses isolated during the past decade from countries participating in WHO's global influenza surveillance network.