

The Spanish flu of 1918 was an H1N1 strain that caused the largest reported fatal pandemic in
human history. The virus spread throughout the world in less than 1 year killing over 40 million
persons. Typical influenza seasons in the USA are associated with 35,000 deaths predominantly
in the frail elderly. The 1918 pandemic killed young healthy adults. The predominant mechanism
of death in young adults was a severe viral pneumonia with bleeding in the lung.
Pandemics also occurred in 1957 (H2N2 Asian flu) and 1968 (H3N2 Hong Kong flu). The mortality
in those years was 70,000 and 34,000 respectively in the United States.
The current Avian flu virus (H5N1) was first noted in a cluster of patients in Hong Kong in 1997.
New outbreaks have occurred in 2003 and 2004 in 8 Asian countries. The mortality in more than
200 cases has been 50%. The complication most often found in these predominantly young
adults was pneumonia similar to the 1918 Spanish flu. Person-to-person transmission was first
reported in 2005 in Thailand where a mother and aunt died after exposure to a critically ill family
member in a hospital setting. So far efficient human-to-human spread has not been observed.
Influenza infection causes an acute illness with fever, muscle aches and respiratory symptoms
such as cough or sore throat. Patients may appear very ill even without complications. Nausea,
vomiting, dehydration and secondary bacterial infection may require patients to seek medical help.
Fluids, control of nausea/vomiting and antivirals could assist the majority of patients who need
help. The virus can be treated with oseltamivir (Tamiflu) if treated early ie: 48 hours.
In most years, the medical delivery system has been able to provide this care without difficulty. The
current challenge is to be prepared to handle the demand in a pandemic of H5N1 influenza.
In a July 2008 New England Journal of Medicine article, a team of researchers reported favorable
immunogenicity and side effects for a whole virus H5N1 vaccine. It remains unclear which virus
will cause a pandemic (ie: H9N2, H5N3, etc.). It may take 6 months to produce a vaccine in the
event of a pandemic. Early therapy of viral sepsis with fluids and early treatment of secondary
infections remain the most practical clinical goals.
Updated November, 2009
Most influenza viruses occur in birds and only a few strains make the
transition to cause human disease. Changes in human influenza virus
proteins results in human-to-human spread of viruses to which we are
not immune. Influenza virus has 2 major surface proteins that are
designated H (hemaglutinin) or N (neuraminidase). The H and N
designation identifies different influenza strains from season to season
Serving Metro Atlanta with offices in: Cumming, Johns Creek and Roswell
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Cumming Office: (678) 341-8035 Johns Creek Office:: (678) 551-6970 Roswell Office: (770) 255-1069
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Northside Hospital Forsyth
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