Division of Public Health and Public Service, Dept Family Medicine, MUSC

South Carolina Agromedicine Program

     SC AgMed Program

Structural Infestation by Imported Fire Ants:
A Survey with Health Implications

( Schuman SH, Simpson WM, and Caldwell ST. Structural Infestation by Imported Fire Ants:
A Survey with Health Implicationsants. J SC Med Assoc 2001; 97:242-245)

SUMMARY: In recent years, entomologists and pest control professionals have noted an increasing tendency for imported fire ant (IFA) colonies to invade indoor structures, attracted by heat, forage and oddly, electrical fields (wiring, etc.). The health implications of the expanding IFA colonies are increasingly evident when confined patients (elderly, convalescents, infants) become victims of unprovoked attack due to interior infestations. A one-page questionnaire was mailed to the state's licensed pest control companies (631) in late December 2000, requesting information for the prior 12 months regarding numbers of structures treated for IFA infestation.

The Agromedicine Program in South Carolina has been fortunate to have consistent teamwork between entomologists at Clemson University, clinicians in practice, and pest control professionals tracking the IFA problem in our state. IFA are more than a garden or lawn nuisance; invading our schools, day care centers, nursing homes, hospitals, businesses and residences. Confined patients are at special risk of serious health effects from unprovoked IFA attacks.This study provides the first baseline estimate of the impact of indoor IFA infestations in all 46 counties of our state. Clinicians need to be alert to the threat of unprovoked stings and possible anaphylaxis among disabled or confined patients in a variety of indoor settings.

This study was funded in part by the Clemson Public Service Program.

Table 1
Survey of Pest Control Companies in South Carolina for Reports of Structural Infestations by Imported Fire Ants in 2000 1

Structures Infested 2
n / %

     Apartments

925 / 8

     Day care centers

305 / 3

     Duplexes

381 / 3

     Eateries

484 / 4

     Food stores

192 / 2

     Hospitals

36 / <1

     Nursing homes

142 / 1

     Offices

858 / 7

     Schools

149 / 1

     Single family homes

8,022 / 67

     Stores

329 / 3

     Other structures 3

63 / <1

     Total

11,886 / 100

   

Health Effects

     People stung indoors

2,318 / 100

     Reports of anaphylaxis

54 / 2.3

Trend 4

     Increasing

176 / 79

     Decreasing

4 / 2

     Same

42 / 19

1 County-specific data are available from the authors on request.

2 1,872 of the infestations were reported to have occurred above the first floors of the structures.

3 Warehouses, churches, motels/hotels, and manufacturing sites

4 Respondents who believed that fire ant structural infestations were increasing, decreasing, or remaining the same during the past 12 months.

Table 2
Imported Fire Ant Infestation Rates per 1,000 Housing Units for Selected Counties as Reported by Pest Control Companies in South Carolina, 2000

County1
Total Infestations
   Housing
Units    Infested2

Total      
Housing Units
In County3

Rate
per
1,000

Lexington
1,717
1,493
67,556
22.1

Kershaw

408

310

17,479

17.7

Charleston

1,507

1,123

123,550

9.1

Horry

780

591

89,960

6.6

Richland

853

693

109,564

6.3

Spartanburg

369

305

89,927

3.4

Greenville

564

419

131,645

3.2

South Carolina

11,886

9,144

1,386,561

6.6

1Specific data for other counties are available from the authors on request.

2Apartments + duplexes + single family homes

3U.S. Bureau of the Census, 1990

 

 

 

grnbar.jpg (7937 bytes)

DFM Home Page         MUSC Home Page         Campus Map

Medical University of South Carolina, South Carolina Agromedicine Program   
295 Calhoun St., Room 103, P.O. Box 250192, Charleston, SC 29425-0192   (843) 792-2281
Questions or Comments: Dr. William Simpson e-mail: simpsowm@musc.edu