2016 Summary of Eastern Equine 

Encephalitis Cases in the United States

January 1 – December 31, 2016

This report is a descriptive summary of U.S. Eastern equine encephalitis (EEE) cases reported to the 

United States Department of Agriculture (USDA) in 2016. The USDA Animal and Plant Health Inspection 

Service (APHIS) Veterinary Services (VS) branch collaborates with the U.S. Centers for Disease Control 

and Prevention (CDC) and State veterinary and public health officials to facilitate communication about 

arbovirus disease cases in horses and confirm equine cases in each State. CDC collects arbovirus case 

information using its ArboNET reporting system, an electronic surveillance and reporting system used to 

track and report arboviral activity in humans and animals. During the transmission season, VS 

disseminates the equine arbovirus case information to State animal health officials for confirmation and 

posts the number of confirmed cases to the USDA equine infectious anemia disease information Web

site (http://www.aphis.usda.gov/animal-health/equine-health). This site also provides specific case 

definitions. In this document, ‘reported cases’ of EEE may include presumptive positive and confirmed 

positive cases. 

In 2016, 118 equine cases of EEE were reported from 15 States. Figure 1 shows the annual number of 

equine EEE cases reported in the U.S. from 2003 through 2016. Figure 2 shows the number of equine 

EEE cases in each State in 2016, and Table 1 provides the number of cases per county or parish in those 

States in 2016. 

Figure 1. Reported U.S. equine cases of Eastern equine encephalitis, 2003-2016

712

133

330

111

206 185

301

247

60

209 192

136

70

118

0

100

200

300

400

500

600

700

800

2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016

Equine Cases of EEE

Animal and Plant 

Health Inspection 

Service

Veterinary 

Services

June 2017
2016 Summary of Eastern Equine Encephalitis Cases in the United States

USDA-APHIS-VS 2

Figure 2. Distribution of reported equine EEE cases in 2016 (118 total cases) 

Table 1. Number of reported equine EEE cases by State and county, 2016

State County Eastern Equine Encephalitis Reported Cases

Alabama Autauga County 1

Baldwin County 3

Mobile County 1

Montgomery County 1

Washington County 1

Total cases for Alabama 7

Arkansas Benton County 1

Total cases for Arkansas 1

Florida Highlands County 2

Jackson County 2

Jefferson County 4

Lake County 1

Marion County 2
2016 Summary of Eastern Equine Encephalitis Cases in the United States

USDA-APHIS-VS 3

Osceola County 5

Palm Beach County 1

Polk County 4

Walton County 1

Washington County 2

Total cases for Florida 24

Georgia Colquitt County 1

Effingham County 1

Lowndes County 1

Pierce County 1

Worth County 1

Total cases for Georgia 5

Louisiana Caddo Parish 5

St. Landry Parish 1

St. Tammany Parish 1

Tangipahoa Parish 5

Vernon Parish 1

Washington Parish 1

Total cases for Louisiana 14

Michigan Clare County 1

Menominee County 1

Total cases for Michigan 2

Mississippi Copiah County 1

George County 1

Greene County 1

Jackson County 1

Lamar County 1

Neshoba County 1

Pearl River County 1

Rankin County 1

Total cases for Mississippi 8

North 

Carolina Pitt County 1

Total cases for North Carolina 1

New Jersey Morris County 2

Ocean County 1

Passaic County 1

Total cases for New Jersey 4

New York Ulster County 1

Seneca County 1
2016 Summary of Eastern Equine Encephalitis Cases in the United States

USDA-APHIS-VS 4

Total Cases for New York 2

South 

Carolina Barnwell County 1

Berkeley County 1

Chesterfield County 1

Colleton County 2

Darlington County 1

Dorchester County 1

Greenville County 1

Horry County 5

Kershaw County 1

Marion County 1

Total cases for South Carolina 15

Tennessee Chester County 1

Madison County 1

Total cases for Tennessee 2

Texas Anderson County 1

Cass County 1

Orange County 1

Smith County 3

Tyler County 1

Total cases for Texas 7

Virginia Accomack County 1

Chesapeake City 1

Prince George County 1

Suffolk City 4

Total cases for Virginia 7

Wisconsin Chippewa County 1

Clark County 1

Eau Claire County 1

Forest County 3

Langlade County 2

Lincoln County 2

Monroe County 1

Taylor County 1

Vilas County 2

Waupaca County 4

Wood County 1

Total cases for Wisconsin 19
2016 Summary of Eastern Equine Encephalitis Cases in the United States

USDA-APHIS-VS 5

Total Reported Eastern Equine Encephalitis Cases for 

the United States 118