title: Evaluation of community-based serologic screening for identification of chronic Salmonella typhi carriers in Vietnam.
abstract: 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.
authors.affiliation: Foodborne and Diarrheal Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA. agupta25@jhmi.edu
authors.forename: A
authors.initials: A
authors.lastname: Gupta
authors.forename: N T
authors.initials: NT
authors.lastname: My Thanh
authors.forename: S J
authors.initials: SJ
authors.lastname: Olsen
authors.forename: S
authors.initials: S
authors.lastname: Sivapalasingam
authors.forename: T T
authors.initials: TT
authors.lastname: My Trinh
authors.forename: N T
authors.initials: NT
authors.lastname: Phuong Lan
authors.forename: R M
authors.initials: RM
authors.lastname: Hoekstra
authors.forename: W
authors.initials: W
authors.lastname: Bibb
authors.forename: N T
authors.initials: NT
authors.lastname: Minh
authors.forename: T P
authors.initials: TP
authors.lastname: Danh
authors.forename: P D
authors.initials: PD
authors.lastname: Cam
authors.forename: E D
authors.initials: ED
authors.lastname: Mintz
mesh_terms: 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
chemical_list: D000907:Antibodies, Bacterial