Temporal and spatial association of Streptococcus suis infection in humans and porcine reproductive and respiratory syndrome outbreaks in pigs in northern Vietnam
HUONG VTL., THANH LV., PHU VD., TRINH DT., INUI K., TUNG N., OANH NTK., TRUNG NV., HOA NT., BRYANT JE., HORBY PW., KINH NV., WERTHEIM HFL.
<jats:title>SUMMARY</jats:title><jats:p>Porcine reproductive and respiratory syndrome (PRRS) outbreaks in pigs are associated with increased susceptibility of pigs to secondary bacterial infections, including <jats:italic>Streptococcus suis</jats:italic> – an important zoonotic pathogen causing bacterial meningitis in humans. This case-control study examined the association between human <jats:italic>S. suis</jats:italic> infection and PRRS outbreaks in pigs in northern Vietnam. We included 90 <jats:italic>S. suis</jats:italic> case-patients and 183 non-<jats:italic>S. suis</jats:italic> 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 <jats:italic>S. suis</jats:italic> 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 <jats:italic>S. suis</jats:italic> infection after adjusting for sex, occupation, and eating practices. SaTScan analysis showed a possible cluster of <jats:italic>S. suis</jats:italic> infection in humans around PRRS confirmed locations during the March–August period. The findings indicate an epidemiological association between PRRS in pigs and <jats:italic>S. suis</jats:italic> infections in humans. Effective strategies to strengthen control of PRRS in pigs may help reduce transmission of <jats:italic>S. suis</jats:italic> infection to humans.</jats:p>