Temporal and spatial association of Streptococcus suis infection in humans and porcine reproductive and respiratory syndrome outbreaks in pigs in northern Vietnam

Abstract

SUMMARYPorcine 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.

Risk factors for Streptococcus suis infection: A systematic review and meta-analysis

“…There were 682 records remaining after removing duplicates in which 636 citations that were proceedings or did not contain risk factors were excluded upon title and abstract screening. There were 32 articles included in systematic review 5 , 9 – 11 , 13 – 40 and 3 case-control studies 19 , 37 , 38 in the meta-analysis after full texts evaluation. The PRISMA flow chart describing the study selection process was shown in Fig.…”

“…Included studies with different study designs were conducted in 9 distinctive countries. Among these, there were 1 randomized double-blind, placebo-controlled trial 10 , 3 case-control studies in which there were 1 matched case-control 37 , 1 retrospective case-control 38 and 1 prospective case-control studies 19 , 28 descriptive studies including 3 public health surveillance studies 27 , 40 , 41 , 2 outbreak investigations 36 , 39 and 1 epidemiological analysis in China 23 , a population-based study on a food safety campaign 30 and a retrospective cohort identifying risk factor for S . suis mortality 34 , 3 retrospective reviews 16 , 20 , 21 and 17 case reports or case series 9 , 11 , 13 – 15 , 17 , 18 , 22 , 24 – 26 , 28 , 29 , 31 – 33 , 35 .…”

“…Majorities of studies were from Asia mainly Thailand, China, Hong Kong and Vietnam. Fourteen studies were from Thailand 16 , 18 , 20 , 21 , 26 – 31 , 33 , 34 , 39 , 40 , four each were from China 23 , 24 , 36 , 37 , Hong Kong 11 , 15 , 22 , 25 and Vietnam 10 , 19 , 35 , 38 , two studies were from the Netherlands 9 , 13 , and one study each from Japan 14 , Serbia 17 , the UK 32 and Togo 41 . Two out of the four articles from China were from epidemiological investigation in Sichuan outbreak in 2005 36 , 37 .…”

Seroprevalences of multi-pathogen and description of farm movement in pigs in two provinces in Vietnam

“…From a public health point of view, it has been suggested that infection of PRRS in pigs was increased by co-infection with Streptococcus suis (S. suis) [28,29], further to one experiment that showed that PRRS infected pigs were more susceptible to S. suis [30]. In Vietnam, some studies showed that significantly more cases of S. suis were observed in a district adjacent to a PRRS district [31,32]. S. suis infection is a zoonotic disease of growing importance in Asia that causes acute meningitis, septicemia and arthritis in humans [33,34].…”

Culture-Negative Streptococcus suis Infection Diagnosed by Metagenomic Next-Generation Sequencing

“…Streptococcus suis infection has nonspecific clinical symptoms in the early stages and progresses rapidly. Mortality rates (0-33.3%) are low compared with meningitis caused by other pathogens (5)(6)(7)(8)(9)(10)(11)(12). However, toxic shock-like syndrome caused by this pathogen has a high mortality rate in China (62 and 50%) and Thailand (80%) (6)(7)(8).…”