Seroepidemiology of infections due to spotted fever group rickettsiae and Ehrlichia species in military personnel exposed in areas of the United States where such infections are endemic.
A prospective, seroepidemiologic study of spotted fever group rickettsiae (SFGR) and Ehrlichia infections was done among 1194 US military personnel exposed in a heavily tick-infested area of Arkansas in 1990. Seroconversion (4-fold) and seroprevalence rates were determined by indirect immunofluorescent antibody assays. Seroconversions to SFGR occurred in 30 persons (2.5%), whereas seroconversion to Ehrlichia species occurred in 15 (1.3%). The majority of seroconverters did not report symptoms (22/30 [73%] of SFGR seroconverters; 10/15 [67%] of Ehrlichia species seroconverters). History of tick attachment was associated with seroconversion to SFGR (relative risk [RR] = 4.3, P < .001) and Ehrlichia species (RR = 3.6, P < .05). Use of permethrin-impregnated uniforms significantly decreased risk of infection (P < .01); use of bed nets increased risk by 4-fold. Tickborne infections represent a significant threat to military personnel training in areas in which these infections are endemic.
Yevich
S J
SJ
Department of Field Studies, Walter Reed Army Institute of Research, Washington, DC, USA.
Sánchez
J L
JL
DeFraites
R F
RF
Rives
C C
CC
Dawson
J E
JE
Uhaa
I J
IJ
Johnson
B J
BJ
Fishbein
D B
DB
D000293:Adolescent; D000328:Adult; D000368:Aged; D000907:Antibodies, Bacterial / Q000097:blood*; D016873:Ehrlichiosis / Q000453:epidemiology* / Q000276:immunology / Q000517:prevention & control; D005260:Female; D006801:Humans; D015994:Incidence; D007306:Insecticides; D008297:Male; D008875:Middle Aged; D008889:Military Personnel; D026023:Permethrin; D015995:Prevalence; D011446:Prospective Studies; D011722:Pyrethrins; D012282:Rickettsia Infections / Q000453:epidemiology* / Q000276:immunology / Q000517:prevention & control; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D014481:United States / Q000453:epidemiology
D000907:Antibodies, Bacterial; D007306:Insecticides; D011722:Pyrethrins; D026023:Permethrin