HEALTHNET

Streptococcus Suis Infection

A mysterious life-threatening disease related to pig was found in China's Sichuan Province and new case has also been reported in Hong Kong.

(Posted on 27 August 2005)

Streptococcus Suis Infection:

Streptococcus suis is an important pathogen of pigs that causes considerable economic damage in countries with an intensive pig industry. Their natural habitat is at the upper respiratory tract (particularly the tonsils and nasal cavities) and pig-to-pig spread is mainly by nose-to-nose contact or by aerosol over short distances.

Human infection with Streptococcus suis is mainly resultant from the contact with infected pigs or their carcasses, products or residues and the clinical outcome may be severe with meningitis, septicaemia, endocarditis, and deafness. Two serotypes have been implicated in human infections: S. suis type 2 and type 14. It is a notifiable occupational disease under the Occupational Safety and Health Ordinance in Hong Kong. From 2004 to July 2005, the Department of Health (DH) recorded a total of ten cases, with 4 reported occupational exposures (one abattoir worker, two pork sellers and a dim sum worker), and the other 6 cases (2 retirees, 1 butcher, 1 merchandiser, 1 construction worker and 1 contractor) having no exposure to pigs or raw pork.

For diseases to be transmitted from hogs to people the causative organism (pathogen) must either be ingested, inoculated, or inhaled.

1. Ingestion: Eating the food contaminated/carrying the infectious organism.
2. Inoculation:
   • via the mucosa of eyes, mouth or nose (e.g. Rubbing the eyes and nose with hands contaminated with the organism)
   • via cuts and abrasions of the skin
   • via sharps and needles penetration
3. Inhalation: Inhale the pathogens directly or droplets containing the pathogens in the air.

Prophylaxis:

1. Prophylactic antibiotics such as penicillin are commonly used in the pig-rearing industry but they rapidly inactivate in feed and thus may fail to control the disease.
2. Although killed vaccines are used, their efficacy is unproved.

Prevention:

1. One should always observe personal and environmental hygiene and avoid contact with pigs that are sick or died from diseases, as well as their excreta or body fluids.
2. If contact with live pigs or raw pork is necessary, one should wear a mask and protective gloves when contacting live pigs; wash hands after handling pigs or raw pork, clean and cover all wounds properly, and avoid injury while processing meat.
3. One should always wash his/her hands before eating, smoking, or touching his/her mouth.
4. Beware of the personal factors that increase the susceptibility of infection such as stress, fatigue, poor general health, pregnancy, and old age. Note that people who have immunosuppression or had their spleens removed are particularly at risk.
5. Persons with suspected symptoms should consult their doctors as soon as possible and report their relevant exposure histories.

Action by HKSAR:

Stop importing pork meat from the endemic area (Sichuan in this occasion).

Source: The University of Hong Kong Li Ka Shing Faculty of Medicine

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