2018 Summary of Eastern Equine 

Encephalitis Cases in the United States

January 1 – December 31, 2018

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

United States Department of Agriculture (USDA) in 2018. 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 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 2018, 107 equine cases of EEE were reported from 13 States. Figure 1 shows the annual number of 

equine EEE cases reported in the U.S. from 2005 through 2018. Figure 2 shows the number of equine 

EEE cases in each State in 2018, and Table 1 provides the number of cases per county or parish in those 

States in 2018. 

Figure 1. Reported U.S. equine cases of Eastern equine encephalitis, 2005-2018

330

111

206

185

301

247

60

209

192

136

70

118

86

107

0

50

100

150

200

250

300

350

2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018

Equine Cases of EEE

EEE Cases

Animal and Plant 

Health Inspection 

Service

Veterinary 

Services

July 2019
2018 Summary of Eastern Equine Encephalitis Cases in the United States

USDA-APHIS-VS 2

Figure 2. Distribution of reported equine EEE cases in 2018 (107 total cases)

Table 1. Number of reported equine EEE cases by State and county, 2018

State County Eastern Equine Encephalitis Reported 

Cases

Alabama Elmore County 2

Geneva County 2

Hale County 1

Houston County 1

Limestone 

County

1

Marshall County 2

Mobile County 1
2018 Summary of Eastern Equine Encephalitis Cases in the United States

USDA-APHIS-VS 3

State County Eastern Equine Encephalitis Reported 

Cases

Total Cases for Alabama 10

Florida Baker County 1

Bradford County 1

Clay County 1

Columbia County 2

Escambia County 1

Flagler County 1

Gilchrist County 2

Hamilton County 1

Jackson County 1

Lake County 2

Levy County 4

Marion County 13

Nassau County 4

Okeechobee 

County

2

Osceola County 2

Pasco County 1

Polk County 2

Putnam County 1

Seminole County 1

St. Johns County 2

Sumter County 1

Suwannee 

County

3

Taylor County 1

Union County 1

Volusia County 3

Total Cases for Florida 54

Georgia Bleckley County 1

Colquitt County 1

Cook County 1

Jenkins County 1

Lowndes County 1

Wayne County 1

Wilkinson County 1

Total Cases for Georgia 7

Indiana Kosciusko County 1

Whitley County 1

Total Cases for Indiana 2
2018 Summary of Eastern Equine Encephalitis Cases in the United States

USDA-APHIS-VS 4

State County Eastern Equine Encephalitis Reported 

Cases

Louisiana Ascension Parish 1

Calcasieu Parish 1

Evangeline Parish 1

Iberia Parish 1

Natchitoches 

Parish

2

Rapides Parish 1

Tangipahoa 

Parish

1

Total Cases for Louisiana 8

Massachusetts Worcester 

County

1

Total Cases for Massachusetts 1

Mississippi Hancock County 1

Harrison County 1

Jackson County 1

Lawrence County 1

Neshoba County 1

Total Cases for Mississippi 5

North Carolina Carteret County 1

Craven County 1

Duplin County 2

Onslow County 2

Richmond 

County

1

Total Cases for North Carolina 7

New Jersey Camden County 1

Gloucester 

County

1

Monmouth 

County

1

Ocean County 2

Total Cases for New Jersey 5

New York Chautauqua 

County

1

Oswego County 1

Washington 

County

1

Total Cases for New York 3

South Carolina Chesterfield 

County

1

Total Cases for South Carolina 1

Virginia Chesapeake City 1

Suffolk City 1
2018 Summary of Eastern Equine Encephalitis Cases in the United States

USDA-APHIS-VS 5

State County Eastern Equine Encephalitis Reported 

Cases

Total Cases for Virginia 2

Wisconsin Oneida County 1

Washburn 

County

1

Total Cases for Wisconsin 2

Total Reported Eastern Equine Encephalitis Cases for the 

United States

107