Streptococcus Suis Infection Clinical Trial
Official title:
Spatial and Temporal Associations Between Human Streptococcus Suis Infections and Pig Diseases in Northern Vietnam, 2010
This study aim to test the hypothesis that human S.suis infections are associated in time and space with outbreaks of Porcine Reproductive and Respiratory Syndrome (PRRS) virus or other diseases in pigs.
Streptococcus suis is a zoonotic agent which can cause severe systemic infection in humans
exposed to infected pigs or pig derived products. Over 700 cases have been reported
worldwide, most of them were in China and Vietnam in the last few years.
In Vietnam, S. suis infection in adults is common, and patients with S.suis are often
admitted to the National Hospital for Tropical Diseases (NHTD), a tertiary referral hospital
for infectious diseases in northern Vietnam. In 2007, 50 laboratory confirmed cases with
S.suis were reported at this hospital, and in 2010, 65 laboratory confirmed S.suis cases
have been identified by September. Pig breeding and pork consumption is popular in Vietnam,
with the majority of pigs and meat supply channelled from small-scaled un-controlled farmers
and slaughterhouses, which pose a great potential health risk to people involved in the
chain. A case-control study conducted in southern Vietnam showed that occupational exposure,
raising pigs at home and consuming high-risk dishes from pigs significantly increased the
risk of S. suis infection.
It has been suggested that the incidence of human S. suis cases is possibly linked to the
occurrence of Porcine Respiratory and Reproductive System (PRRS) virus outbreaks in northern
Vietnam. In 2010, the disease has spread to over 30 provinces over the country, with many
outbreaks reported in northern provinces in the period from April to July. Field
observations in other countries showed that PRRS virus infection increased pig's
susceptibility to S. suis infection, including serotype 2 and 7. Therefore, PRRS virus
outbreaks might have increased the risk of S. suis transmission to humans through exposure
to pigs with PRRS virus infection and concomitant S. suis disease. Nevertheless, sufficient
data are not available to confirm or refute this hypothesis. Knowledge of spatial and
temporal relationships between human S.suis infections and disease outbreaks in pigs can
increase our understanding of risk factors for human S.suis infection and support disease
prevention and preparedness in the community.
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Observational Model: Case Control, Time Perspective: Retrospective