Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
Influenza viruses are
small RNA viruses that infect many mammals, including humans, birds, and swine.
Before 2009, swine influenza predominately affected swine and was not
transmitted often or easily to people. Even in the isolated instances in which
swine influenza infected people, it had very limited ability to spread from
person to person. Most cases were directly linked to contact with swine through
farming or at fairs. Since 2009, the interactions and understanding of the role of swine and flu viruses in human infections has been markedly changed.
Swine were first noticed to have influenza-like illnesses in 1918 during the human influenza pandemic. The term "pandemic" means that an infection has spread to many countries around the world, causing widespread human disease. Swine influenza did not cause the 1918 pandemic. Rather, pigs apparently acquired the infection from humans or from an undiscovered source. For decades, the swine virus remained relatively unchanged. In the 1990s, however, swine influenza viruses became more diverse and new strains appeared. The reason for this change is not clear but may have been related to overcrowding on large swine farms.
Before 2009, there was only one swine influenza outbreak in people that
caused public-health concerns. This outbreak occurred in 1979, in soldiers at
Fort Dix, N.J. One recruit died, and approximately 12 were hospitalized
with influenza. Further testing showed that more than 200 recruits had acquired
the virus, although most had few or no symptoms. The infecting strain was found
to be strongly related to swine influenza virus, raising concerns that a new
pandemic might occur. In response, public-health officials began a massive
public vaccination program. Up to 25% of people in the United States were
vaccinated. Unfortunately, the 1979 vaccine was associated with a small
increased risk of Guillain-Barré syndrome, a serious neurological condition,
with the risk estimated to be one to nine excess cases per million doses.
Importantly, the 1979 strain did not spread easily from person to person and
there was no epidemic. Human cases outside of Fort Dix were uncommon. Moreover, the 1979 vaccine was made using an old-fashioned process which is no longer utilized.
The lessons learned from the 1979 swine influenza event were applied in dealing with pandemic threats, including the severe acute respiratory syndrome (SARS) outbreak of 2003 and the 2009 influenza outbreak. Key lessons included ensuring adequate communication with the public, producing a rapid but measured response to potential threats, and ensuring that any new strain fulfills criteria to cause a pandemic before large-scale vaccination was undertaken.
Swine Flu Symptoms...What to Do? One ER Doctor's Perspective
Medical Author: Benjamin C. Wedro, MD, FAAEM
Medical Editors: Melissa Conrad Stöppler, MD
As cases of swine flu are being confirmed around the
world, governments are ramping up their disease control plans to hopefully
minimize the effects of this infection. According to the World Health Organization,
"Given the widespread
presence of the virus...containment of the outbreak is not feasible. The current
focus should be on mitigation measures." This means that preventing spread of
the virusis not likely, and treating outbreaks will be important in minimizing
the numbers of people who might become ill and potentially die.
Swine flu is no different that any other
influenza-likedisease when it comes to symptoms:
body aches, and
Aside from the chills and shakes, these sound similar to the
symptoms of a severe cold. Whether that's all there is or whether
a person will become
significantly ill is difficult to predict. Individuals with poor immune systems,
infants and the elderly, those undergoing chemotherapy treatment, or taking medications that impair
immunity, are at higher risk for more severe illness. But even healthy people can
become sick. The virus spreads by aerosoldroplets, meaning that secretions from an
infected person can be spread into the air by coughing or sneezing. It's the
close contact with an ill person that causes the disease to spread. And a person
may be contagious for 24 hours before any symptoms occur.
How a community, a hospital, or an individual deals with the potential for
infection will help decide how fast and how far it will spread.