From the Editor

Friday, December 23, 2016 Published in On-Demand Winter 2013 Written by David Persing M.D., Ph.D., Chief Medical and Technology Officer, Cepheid

In this issue of On Demand, Dr. Ellen Jo Baron provides a wealth of information on our perennial foe, the influenza virus. If you want to get up to speed on this subject quickly, read this issue; it encapsulates much of the recent research on the flu viruses, their virulence factors, and approaches to their detection. As many of you know, rapid detection of this virus during the flu season is of significant medical value, but until recently, most of the rapid tests have not been sensitive enough to rule out influenza infection with a high degree of confidence. Next-generation molecular diagnostic testing for influenza virus and specifically the Xpert® Flu cartridge represent game-changing technologies. I hope you enjoy reading this issue as much as I have.

Case Study Award: Cepheid Xpert® Flu Assay Results: Positive in More than One Way

Friday, December 23, 2016 Published in On-Demand Winter 2013 Written by Ellen Jo Baron, Ph.D., D(ABMM), Prof. Emerita, Stanford University Director of Medical Affairs, Cepheid

Jack L. Brothers, MT(ASCP), Microbiology Technical Supervisor, works at a surprisingly beautiful hospital (Figure 1) in an unlikely place: Anchorage, Alaska. The Joint Base Elmendorf-Richardson is the largest U.S. military installation in Alaska and was created when former Elmendorf Air Force and Fort Richardson Army bases were merged in 2010.

Influenza today: Still a hot topic on many fronts

Friday, December 23, 2016 Published in On-Demand Winter 2013 Written by Ellen Jo Baron, Ph.D., D(ABMM), Prof. Emerita, Stanford University Director of Medical Affairs, Cepheid

It seems like just yesterday that influenza was on everyone’s minds, but it has been almost a year since we featured influenza in an edition of On Demand. The novel influenza A H1N1 strain that caught everyone by surprise in 2009 seems to have become a very minor component of the circulating strains now, except in the Middle East and India, where it still predominates. This season, influenza B is prominent in the Americas and Africa, and influenza A H3N2 comprises half the reported cases in Europe and Australia, and more than 75% of strains in ChinaA. The World Health Organization reported that the most common strain worldwide, A(H3N2), is again targeting the traditional at-risk age groups of >60 years and <2 years. In temperate South America, numbers of influenza cases began to increase in May, peaking around July with the largest numbers seen for A(H3N2), but showing a second peak in August with more influenza B strains and untyped influenza A strains Figure 1. There was a sharp drop-off in September, heralded by the disappearance of almost all influenza A reports. Africa peaked in July, but numbers remained high into September, with influenza B assuming the majority of cases. The United States is just beginning its influenza season, so the epidemiology is not known yet Figure 2. Overall, influenza activity is lower than historical levels. This may be a result of increasing numbers of Americans receiving their annual flu vaccine. However, a new virus, variant H3N2 (H3N2v), associated with pigs and originally discovered in 2011, has cropped up this year in some human outbreaks periodically since July, 2012.1,B Although the strains of influenza circulating globally now are genetically slightly different from those in the current vaccine, the CDC feels that there will be significant cross-reactive protection, so they recommend that the vaccines not be changed. The common viruses causing disease are generally susceptible to both neuraminidase inhibitor antiviral agents oseltamivir (Tamiflu®) and zanamivir (Relenza®). This correlates with the seeming disappearance of the previously circulating H1N1 strain (called “seasonal”) that was resistant to oseltamivir. Of course, occasional resistance can arise and patients who fail to improve after a week of therapy should be evaluated for drug resistant strains, as well as for other complications. Zanamivir is not recommended for patients <7 years old or for those with underlying respiratory disease. The CDC treatment guidelines state that antiviral therapy should not be delayed while waiting for diagnostic test results when clinical indications suggest influenza and antiviral treatment is indicated.C