"invasive" group A streptococcal disease?
A case of invasive disease
is confirmed when GAS is isolated from a normally sterile site, such as
blood. When GAS is cultured from a nonsterile wound from a patient with
necrotizing fasciitis or streptococcal toxic shock syndrome, this is also
considered evidence of invasive GAS disease.
What if my investigation
spans more than a calendar month? For example, what should I enter if I
begin an investigation March 20th, and today is April 3rd?
Use any 30-day period of interest for the current month, and use the
previous 30-day period as the previous month. Choose the calendar month
with the most days in the 30- day period. You may also choose to run the
model twice choosing different months or defining the 30-day period
How do you define
population in a region?
If your county has more than 250,000
people, use the county population. If your county has less than 250,000 population, combine
neighboring counties with similar characteristics (e.g., rural with rural)
until the total population is more than 250,000. Make sure to include any
invasive group A streptococcal (GAS) cases in all counties in the region. Because
invasive GAS infections are uncommon, the region
population must be at least 250,000 to produce a valid prediction.
Why do I need to input
the percentage of population that is African American if the cases in this
cluster are not African American? What if I don't know the racial
breakdown of my population?
African Americans have higher rates of invasive GAS disease
than Caucasians for unknown reasons. Counties or regions that have higher
percentages of African American population therefore have higher expected disease
rates. You can run the model twice using both a high and a low estimate of
the percent African American population in a region.
How do I estimate my
Land area in square miles is available from U.S. census at
http://quickfacts.census.gov/qfd/. Add together the area of all
counties in a region to get a total.
Why do I need to input
the percentage of invasive GAS cases in my region that occur in persons
with HIV-infection or who inject drugs? Are these necessary? What is meant
Invasive GAS infections are
more common in persons with HIV infection and in those who inject drugs.
Including these percentages improves the model, however, these percentages are not required. "Historically" refers to
cases in your region over an extended period of time, such as the past 12
months. If there are no cases related to HIV or injection drug use in your
region, enter zero. If both variables are left blank, the model will
calculate a prediction without these two variables.
Where do I find the mean
temperature for my region? What should I enter if the mean temperature of
my region is different than that of the state?
An internet site is provided
mean temperature of the entire state during the month. The model uses
these values to account for climatic differences in different parts of the
country. You may wish to enter the mean temperature of your county or region,
if that is available.
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