Evaluation of community-based serologic screening for identification of chronic Salmonella typhi carriers in Vietnam.
OBJECTIVE
To determine the utility of screening anti-Vi antibodies to detect chronic Salmonella Typhi carriers in an endemic community.


METHODS
We conducted a community-based serologic survey for anti-Vi antibodies to identify chronic Salmonella Typhi carriers in a typhoid endemic region in Vietnam.


RESULTS
We tested sera from 3209 (67.2%) of 4772 eligible adults. The median age was 37 years (range 20-92), 57.3% were female, 4.6% reported a history of typhoid fever and 0.3% reported typhoid vaccination. Anti-Vi antibody titers tested in Vietnam were < 1:40 in 2759 (86.0%), 1:40 in 194 (6.0%), 1:80 in 168 (5.2%), 1:160 in 57 (1.8%), and > or = 1:320 in 31 (1.0%). On re-testing in the USA, an additional 19 sera with titers > or = 1:160 were identified. We collected 589 rectal swabs from 103 (96.3%) of 107 persons with Vi antibody titers > or = 1:160 and 183 swabs from 33 persons with antibody titers < 1:80. No Salmonella Typhi was isolated.


CONCLUSIONS
Community-based serologic screening is a feasible, but impractical method for identifying chronic Salmonella Typhi carriers. Background levels of anti-Vi antibody titers in this endemic area may be high despite a low prevalence of chronic carriers.
Gupta
A
A
Foodborne and Diarrheal Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA. agupta25@jhmi.edu
My Thanh
N T
NT
Olsen
S J
SJ
Sivapalasingam
S
S
My Trinh
T T
TT
Phuong Lan
N T
NT
Hoekstra
R M
RM
Bibb
W
W
Minh
N T
NT
Danh
T P
TP
Cam
P D
PD
Mintz
E D
ED
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000097:blood*; D002353:Carrier State / Q000175:diagnosis* / Q000382:microbiology; D002908:Chronic Disease; D003153:Community Health Services; D005260:Female; D006386:Hemagglutination Tests; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D012485:Salmonella typhi / Q000276:immunology*; D014435:Typhoid Fever / Q000175:diagnosis* / Q000382:microbiology; D014744:Vietnam
D000907:Antibodies, Bacterial