8.7: Influenza
- Page ID
- 212715
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Influenza
Influenza, popularly known simply as “the flu” is an airborne infectious disease that generally spreads when someone sneezes or coughs microscopic pathogens (germs) into the air. The flu kills thousands of people each year. Sometimes, flu outbreaks are regional and last only a few months. These short-lived regional outbreaks of diseases are called epidemics. Occasionally, diseases like the flu get out of control, spreading across vast areas and lasting for many months. Massive, worldwide disease outbreaks such as these are termed pandemics. The most infamous flu pandemic was the dreaded Spanish Flu that broke out during World War I and killed somewhere from 50 to 100 million people. Nearly the entire globe was affected, and poor countries, like India and China, suffered exceptionally high death tolls. In the United States, over 1/4th of the population was infected. Over one-half million Americans died from it, far exceeding the number of Americans that died in fighting in World War I.
Recently, a version of the Spanish Flu (now called H1N1) returned. It was declared a global pandemic and generated worldwide panic. Nobody is sure where the flu strain began or where patient zero (index case) lived, but the epidemiologists traced the first obvious signs of the pandemic to Veracruz Mexico. There, factory-style hog farming may have created conditions ideal for the first known cases to develop and diffuse around January of 2009.
Figure : Canoga Park, CA. This billboard appeared in LA’s San Fernando Valley in early 2010 as part of a large public health campaign to dampen the effects of the H1N1 influenza outbreak. The campaign was generally successful. (Link to photo within shared album)
By April 2009, it was clear the flu was rapidly spreading in Mexico. In response, officials drastically curtailed public activity in Mexico City. The European Union Health Commission issued travel advisories, urging people not to travel to Mexico, or the United States, where flu cases were beginning to appear. A variety of quarantine orders swept the globe, keeping people in motels, on cruise ships, and in airports. After about six months, the incidence of new flu cases began to fall, and by February 2010, the pandemic was over. The 2009-2010 flu pandemic officially killed 18,000 worldwide, but other estimates suggest as many as 500,000 died because so many deaths were in parts of Africa and Asia where few laboratories exist capable of confirming the exact causes of death. In the United States, where the public health system responded quickly and efficiently, Americans appear to have suffered only about 10,000 deaths from H1N1, which was nearly normal for a flu season.
Figure US Map by State. The severity of the flu by state in October, 2009. Note the contagion pattern from Southwest to Northeast. The color ramp violates standard cartographic principle – how? Source: FluView, CDC
Cool Map:
An interactive mapping program from the Centers for Disease Control
While the 2009 version of H1N1 was apparently less dangerous than its 1918 ancestor, the activity of health departments around the world was essential in averting disaster. Geographers working at the CDC in Atlanta, Georgia knew that a flu outbreak diffusing outward from Mexico were likely to appear first in California or Texas. Indeed, the first American cases appeared in San Diego and Imperial Counties, California, on the Mexican border. Other early cases were in Texas. Armed with data from previous flu outbreaks, computer models and GIS technologies, health geographers working at the CDC were able to accurately predict where, when the flu would flare up in various parts of the United States. Being able to predict the spatial patterns of disease helps health officials direct vaccines and other resources necessary to combat diseases to locations where populations are most at-risk. The outsized effort by the CDC and other public health agencies probably saved thousands of lives in 2009-10.