Human Biology 115A: Humans and Viruses Professor Robert David Seigel

Aaron Platt-Ross aaronpr@stanford.edu

Developments in Bird Flu

CDC MMWR for February 13, 2004 Outbreaks of Avian Influenza A (H5N1) in Asia and Interim Recommendations for Evaluation and Reporting of Suspected Cases --- United States, 2004	From December 2003 through early February 2004 outbreaks of influenza A H5N1 occurred in poultry throughout Asia. This virus developed into a zoonosis, infecting largely younger patients, with a very high fatality rate. The virus is resistant to antiviral drugs used to combat influenza.
Harvey et al. 2004 Restrictions to the Adaption of Influenza A Virus H5 Hemagglutinin to the Human Host	Harvey et al elucidated the ability of avian H5N1 to cross the species barrier to become a human virus. They determined a crystal structure for the hemagglutinin protein on an H5N1 virus, amplified the cDNA for this structure, and established the amino acid mutations responsible for the strand transmitted to humans. The paper concludes that modifications to the proteins favor ability to bind human receptors and that this progresses in a stepwise fashion. A pandemic could result if such these viruses become able to transmit between humans.
Koopmans et al. 2004 Transmission of H7N7 avian influenza A virus to human beings during a large outbreak in commercial poultry farms in the Netherlands	H7N7 broke out in the Netherlands in February 2003 among people in contact with poultry. Koopmans et al surveyed those complaining of symptoms arising from. The virus caused disease in 1 in 10 of those at risk for contraction, a much higher rate than for H5N1. However, the virus responded well to antivirals. Had the virus been more virulent, the authors worried, it could have caused a pandemic. They see the results of their outbreak investigation as a warning that we need to develop improved preparedness plans, stockpiles of vaccines, and antivirals.
Fouchier et al. 2004 Avian influenza A virus (H7N7) associated with human conjunctivitis and a fatal case of acute respiratory distress syndrome	This paper isolated the H7N7 virus responsible for the Netherlands outbreak and determined the specific amino acid changes responsible for the more pathogenic virus in poultry than in wild foul. Houchier et al stressed H7N7's inability to replicate efficiently in the respiratory tract, making human-to-human transmission difficult. The virus also was not a likely product of antigenic shift. The cause of the one fatality due to the virus is unclear.