Mammalian-transmissible H5N1 influenza: facts and perspective

Michael T Osterholm1, Nicholas S Kelley

  • 1Center for Infectious Disease Research and Policy, University of Minnesota, Minneapolis, Minnesota, USA. mto@umn.edu

Mbio
|February 28, 2012
PubMed

Insights

Highly transmissible H5N1 influenza A virus strains raise concerns. This review examines H5N1 case-fatality rates and the limited impact of medical countermeasures during a potential pandemic.

Area of Science:

  • Virology
  • Epidemiology
  • Public Health

Background:

  • Recent studies created transmissible H5N1 influenza A virus variants in ferrets.
  • Concerns exist regarding human-to-human transmissibility of lab-generated H5N1.
  • Debates surround H5N1 case-fatality rates and the efficacy of medical countermeasures.

Purpose of the Study:

  • To review H5N1 seroepidemiology data.
  • To analyze how case-finding strategies affect reported H5N1 case-fatality rates.
  • To assess the potential impact of medical countermeasures during an H5N1 pandemic.

Main Methods:

  • Review of existing seroepidemiology data for H5N1 infection.
  • Analysis of case-finding strategies and their influence on WHO-reported case-fatality rates.
  • Evaluation of the potential effectiveness of medical countermeasures.

Main Results:

  • Case-finding strategies significantly influence the reported H5N1 case-fatality rate.
  • Available medical countermeasures (vaccines, antivirals) would likely have limited impact on morbidity and mortality in an H5N1 pandemic.
  • The transmissibility and public health implications of novel H5N1 strains are under scrutiny.

Conclusions:

  • The true H5N1 case-fatality rate may be lower than reported due to case-finding methods.
  • Medical countermeasures are unlikely to significantly mitigate the impact of a widespread H5N1 influenza pandemic.
  • Further research and public health preparedness are crucial for addressing potential H5N1 threats.

Related Concept Videos

Influenza01:27

Influenza

Influenza is an acute, highly communicable viral disease that affects the respiratory tract and is responsible for seasonal epidemics worldwide. Influenza A is the most prevalent type associated with widespread outbreaks and is subtyped based on two surface glycoproteins: hemagglutinin (H) and neuraminidase (N), as in H1N1. These glycoproteins are essential for viral infectivity, transmission, and immune recognition. Transmission occurs primarily through respiratory droplets and contaminated...
Viral Recombination00:57

Viral Recombination

Cells are sometimes infected by more than one virus at once. When two viruses disassemble to expose their genomes for replication in the same cell, similar regions of their genomes can pair together and exchange sequences in a process called recombination. Alternatively, viruses with segmented genomes can swap segments in a process called reassortment.
Viral Mutations00:36

Viral Mutations

A mutation is a change in the sequence of bases of DNA or RNA in a genome. Some mutations occur during replication of the genome due to errors made by the polymerase enzymes that replicate DNA or RNA. Unlike DNA polymerase, RNA polymerase is prone to errors because it is not capable of “proofreading” its work. Viruses with RNA-based genomes, like HIV, therefore accrue mutations faster than viruses with DNA-based genomes. Because mutation and recombination provide the raw material for adaptive...
Infectious Diseases and Their Occurrence01:28

Infectious Diseases and Their Occurrence

Infectious diseases appear in populations through various transmission patterns, influenced by pathogen characteristics, population immunity, environmental conditions, and social behavior. Understanding these patterns is essential for effective public health surveillance and intervention. These categories—sporadic, outbreak, epidemic, pandemic, and endemic—help frame the nature and scope of disease events.Sporadic diseases occur irregularly and infrequently, without a predictable temporal or...
Leaky Scanning02:28

Leaky Scanning

During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA.  Marilyn Kozak discovered that the sequence RCCAUGG (where R stands for...