title: Temporal and spatial association of Streptococcus suis infection in humans and porcine reproductive and respiratory syndrome outbreaks in pigs in northern Vietnam.
abstract: Porcine reproductive and respiratory syndrome (PRRS) outbreaks in pigs are associated with increased susceptibility of pigs to secondary bacterial infections, including Streptococcus suis - an important zoonotic pathogen causing bacterial meningitis in humans. This case-control study examined the association between human S. suis infection and PRRS outbreaks in pigs in northern Vietnam. We included 90 S. suis case-patients and 183 non-S. suis sepsis controls from a referral hospital in Hanoi in 2010, a period of major PRRS epizootics in Vietnam. PRRS exposure was determined using data from the National Centre of Veterinary Diagnosis. By univariate analysis, significantly more S. suis patients were reported residing in or adjacent to a PRRS district compared to controls [odds ratio (OR) 2·82, 95% confidence interval (CI) 1·35-5·89 and OR 3·15, 95% CI 1·62-6·15, respectively]. Only residency in adjacent districts remained significantly associated with risk of S. suis infection after adjusting for sex, occupation, and eating practices. SaTScan analysis showed a possible cluster of S. suis infection in humans around PRRS confirmed locations during the March-August period. The findings indicate an epidemiological association between PRRS in pigs and S. suis infections in humans. Effective strategies to strengthen control of PRRS in pigs may help reduce transmission of S. suis infection to humans.
authors.affiliation: Wellcome Trust Major Overseas Programme,Oxford University Clinical Research Unit,Hanoi,Vietnam.
authors.forename: V T L
authors.initials: VT
authors.lastname: Huong
authors.affiliation: Wellcome Trust Major Overseas Programme,Oxford University Clinical Research Unit,Hanoi,Vietnam.
authors.forename: L V
authors.initials: LV
authors.lastname: Thanh
authors.affiliation: National Hospital for Tropical Diseases,Hanoi,Vietnam.
authors.forename: V D
authors.initials: VD
authors.lastname: Phu
authors.affiliation: National Hospital for Tropical Diseases,Hanoi,Vietnam.
authors.forename: D T
authors.initials: DT
authors.lastname: Trinh
authors.affiliation: Food and Agriculture Organization,Hanoi,Vietnam.
authors.forename: K
authors.initials: K
authors.lastname: Inui
authors.affiliation: Epidemiology Division,Department of Animal Health,Hanoi,Vietnam.
authors.forename: N
authors.initials: N
authors.lastname: Tung
authors.affiliation: National Centre of Veterinary Diagnosis,Hanoi,Vietnam.
authors.forename: N T K
authors.initials: NT
authors.lastname: Oanh
authors.affiliation: National Hospital for Tropical Diseases,Hanoi,Vietnam.
authors.forename: N V
authors.initials: NV
authors.lastname: Trung
authors.affiliation: Nuffield Department of Clinical Medicine,University of Oxford,Oxford,UK.
authors.forename: N T
authors.initials: NT
authors.lastname: Hoa
authors.affiliation: Wellcome Trust Major Overseas Programme,Oxford University Clinical Research Unit,Hanoi,Vietnam.
authors.forename: J E
authors.initials: JE
authors.lastname: Bryant
authors.affiliation: Wellcome Trust Major Overseas Programme,Oxford University Clinical Research Unit,Hanoi,Vietnam.
authors.forename: P W
authors.initials: PW
authors.lastname: Horby
authors.affiliation: National Hospital for Tropical Diseases,Hanoi,Vietnam.
authors.forename: N V
authors.initials: NV
authors.lastname: Kinh
authors.affiliation: Wellcome Trust Major Overseas Programme,Oxford University Clinical Research Unit,Hanoi,Vietnam.
authors.forename: H F L
authors.initials: HF
authors.lastname: Wertheim
mesh_terms: D000818:Animals; D004196:Disease Outbreaks / Q000662:veterinary*; D006801:Humans; D019318:Porcine Reproductive and Respiratory Syndrome / Q000453:epidemiology* / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000502:physiology*; D012307:Risk Factors; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D017011:Streptococcus suis / Q000502:physiology*; D013552:Swine; D014744:Vietnam / Q000453:epidemiology
keywords: Case-control; Streptococcus suis; Vietnam; pigs; porcine reproductive and respiratory syndrome; secondary infection; zoonosis