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Streptococcus suis Infection

Streptococcus suis Infection

16 November 2018

Causative agent

Streptococcus suis infection is a bacterial infection caused by Streptococcus suis (S. suis). It is a notifiable infectious disease in Hong Kong.

Clinical features

The disease most commonly presents as meningitis with fever, headache and vomiting. It may also present with skin bleeding and less commonly, sepsis, endocarditis, arthritis, bronchopneumonia and toxic shock syndrome. The characteristic complication of S. suis infection is deafness which is likely to remain permanent.

Mode of transmission

S. suis infection is a common disease among pigs. The bacterium is carried in the upper respiratory tract of pigs, and spread among pigs by nose-to-nose contact or by aerosol over short distances. Apart from pigs (including wild boars), it can also be occasionally found in other animals such as horses, dogs, cats and birds.

Human infection by S. suis occurs mainly in adults. It is transmitted through direct contact and often related to exposure through wounds on the skin while handling infected pigs or other animals, uncooked pork and other pig products. But it may also be transmitted via ingestion or through mucous membranes.

High risk groups

People at risk include pig breeders, abattoir workers, meat processing and transport workers, butchers, and cooks. Persons who are immunocompromised including those with the spleen removed, persons with diabetes mellitus, cancer and alcoholism, are also at greater risk of infection.

Incubation period

Ranges from a few hours to two weeks.


S. suis infection can be treated with antibiotics.


There is no human vaccine available for S. suis. The public should adopt the following measures to reduce the risk of infection:

Personal hygiene

  • Avoid contact with pigs (including wild boars) and other animals.
  • When handling pigs or raw pork, wear protective gloves and avoid injury.
  • Wash hands thoroughly after handling pigs or raw pork.
  • Disinfect and cover wounds properly.

Food hygiene

  • Raw pork and cooked food should be handled and kept separately.
  • Pork should be cooked thoroughly before consumption.
  • Do not bring meat into Hong Kong without a permit.

People with suspected symptoms should consult their doctor as soon as possible and report their relevant exposure history.