using reading thats downloaded below  and Accessing the CDC self study modules with the web link provided- Review Lesson 1 (Section 1,2 ,3 and 4)
 
https://www.cdc.gov/csels/dsepd/ss1978/lesson1/section1.html
https://www.cdc.gov/csels/dsepd/ss1978/lesson1/section2.html
https://www.cdc.gov/csels/dsepd/ss1978/lesson1/section3.html
https://www.cdc.gov/csels/dsepd/ss1978/lesson1/section4.html

In August 1999, epidemiologists learned of a cluster of cases of encephalitis caused by West Nile virus infection among residents of Queens, New York. West Nile virus infection, transmitted by mosquitoes, had never before been identified in North America.

Describe how this information might be used for each of the following:

Assessing the community’s health
Making decisions about individual patients
Documenting the clinical picture of the illness
Searching for causes to prevent future outbreaks