title: Risk factors of Streptococcus suis infection in Vietnam. A case-control study.
abstract: BACKGROUND
  Streptococcus suis infection, an emerging zoonosis, is an increasing public health problem across South East Asia and the most common cause of acute bacterial meningitis in adults in Vietnam. Little is known of the risk factors underlying the disease.
  
  
  RESULTS
  A case-control study with appropriate hospital and matched community controls for each patient was conducted between May 2006 and June 2009. Potential risk factors were assessed using a standardized questionnaire and investigation of throat and rectal S. suis carriage in cases, controls and their pigs, using real-time PCR and culture of swab samples. We recruited 101 cases of S. suis meningitis, 303 hospital controls and 300 community controls. By multivariate analysis, risk factors identified for S. suis infection as compared to either control group included eating "high risk" dishes, including such dishes as undercooked pig blood and pig intestine (OR(1) = 2.22; 95%CI = [1.15-4.28] and OR(2) = 4.44; 95%CI = [2.15-9.15]), occupations related to pigs (OR(1) = 3.84; 95%CI = [1.32-11.11] and OR(2) = 5.52; 95%CI = [1.49-20.39]), and exposures to pigs or pork in the presence of skin injuries (OR(1) = 7.48; 95%CI = [1.97-28.44] and OR(2) = 15.96; 95%CI = [2.97-85.72]). S. suis specific DNA was detected in rectal and throat swabs of 6 patients and was cultured from 2 rectal samples, but was not detected in such samples of 1522 healthy individuals or patients without S. suis infection.
  
  
  CONCLUSIONS
  This case control study, the largest prospective epidemiological assessment of this disease, has identified the most important risk factors associated with S. suis bacterial meningitis to be eating 'high risk' dishes popular in parts of Asia, occupational exposure to pigs and pig products, and preparation of pork in the presence of skin lesions. These risk factors can be addressed in public health campaigns aimed at preventing S. suis infection.
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam.
authors.forename: Ho Dang Trung
authors.initials: HD
authors.lastname: Nghia
authors.forename: Dang Trung Nghia
authors.initials: DT
authors.lastname: Ho
authors.forename: Le Thi Phuong
authors.initials: le TP
authors.lastname: Tu
authors.forename: Thi Phuong Tu
authors.initials: TP
authors.lastname: Le
authors.forename: Marcel
authors.initials: M
authors.lastname: Wolbers
authors.forename: Cao Quang
authors.initials: CQ
authors.lastname: Thai
authors.forename: Quang Thai
authors.initials: QT
authors.lastname: Cao
authors.forename: Nguyen Van Minh
authors.initials: NV
authors.lastname: Hoang
authors.forename: Van Minh Hoang
authors.initials: VM
authors.lastname: Nguyen
authors.forename: Tran Vu Thieu
authors.initials: TV
authors.lastname: Nga
authors.forename: Vu Thieu Nga
authors.initials: VT
authors.lastname: Tran
authors.forename: Le Thi Phuong
authors.initials: le TP
authors.lastname: Thao
authors.forename: Thi Phuong Thao
authors.initials: TP
authors.lastname: Le
authors.forename: Nguyen Hoan
authors.initials: NH
authors.lastname: Phu
authors.forename: Hoan Phu
authors.initials: HP
authors.lastname: Nguyen
authors.forename: Tran Thi Hong
authors.initials: TT
authors.lastname: Chau
authors.forename: Thi Hong Chau
authors.initials: TH
authors.lastname: Tran
authors.forename: Dinh Xuan
authors.initials: DX
authors.lastname: Sinh
authors.forename: Xuan Sinh
authors.initials: XS
authors.lastname: Dinh
authors.forename: To Song
authors.initials: TS
authors.lastname: Diep
authors.forename: Song Diep
authors.initials: SD
authors.lastname: To
authors.forename: Hoang Thi Thanh
authors.initials: HT
authors.lastname: Hang
authors.forename: Thi Thanh Hang
authors.initials: TT
authors.lastname: Hoang
authors.forename: Hoang
authors.initials: H
authors.lastname: Truong
authors.forename: James
authors.initials: J
authors.lastname: Campbell
authors.forename: Nguyen Van Vinh
authors.initials: NV
authors.lastname: Chau
authors.forename: Van Vinh Chau
authors.initials: VV
authors.lastname: Nguyen
authors.forename: Nguyen Tran
authors.initials: NT
authors.lastname: Chinh
authors.forename: Tran Chinh
authors.initials: TC
authors.lastname: Nguyen
authors.forename: Nguyen Van
authors.initials: NV
authors.lastname: Dung
authors.forename: Van Dung
authors.initials: VD
authors.lastname: Nguyen
authors.forename: Ngo Thi
authors.initials: NT
authors.lastname: Hoa
authors.forename: Thi Hoa
authors.initials: TH
authors.lastname: Ngo
authors.forename: Brian G
authors.initials: BG
authors.lastname: Spratt
authors.forename: Tran Tinh
authors.initials: TT
authors.lastname: Hien
authors.forename: Tinh Hien
authors.initials: TH
authors.lastname: Tran
authors.forename: Jeremy
authors.initials: J
authors.lastname: Farrar
authors.forename: Constance
authors.initials: C
authors.lastname: Schultsz
mesh_terms: D000328:Adult; D017677:Age Distribution; D000818:Animals; D002353:Carrier State / Q000382:microbiology; D016022:Case-Control Studies; D005260:Female; D006761:Hospitals; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016133:Polymerase Chain Reaction; D012307:Risk Factors; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D017011:Streptococcus suis / Q000235:genetics / Q000502:physiology*; D034421:Sus scrofa / Q000382:microbiology; D014744:Vietnam / Q000453:epidemiology