9 August 2005

Streptococcus suis outbreak - China

The World Health Organization (WHO) have recently reported on a human disease in China associated with an outbreak of Streptococcus suis in pigs [1]. According to the Chinese Ministry of Health, there have been 206 human cases of disease up to 3 August 2003. Of these cases, 38 have been fatal and 18 remain critically ill. Nearly all of the cases have originated from eleven prefectures in Sichuan province; the initial cases were reported from Ziyang City beginning 24 June 2005. Sichuan province has one of the largest pig populations in China. The Chinese authorities are taking rigorous measures to investigate and contain the outbreak. It should be stressed that investigation of this outbreak is ongoing and the etiology has not been determined definitively.

Clinical symptoms reported in the human cases include high fever, malaise, nausea and vomiting, followed by meningitis, subcutaneous haemorrhage, shock and coma. Disease progression has been rapid.

Initial epidemiological investigations show that the risk of disease is greatest amongst those who have had close contact with live or slaughtered pigs infected with S. suis; most of the reported cases have been in adult male farmers. In this outbreak, no cases of human to human transmission have been reported.

S. suis is usually found asymptomatically in pigs. It can result in septicaemia, pneumonia, meningitis and arthritis, particularly in young pigs. It has been a rare infection in humans. Human cases that have occurred are usually transmitted via cuts and minor abrasions to the skin.  However, infection via ingestion or through mucous membranes cannot be ruled out.

Currently there are no restrictions on travel to China.

Travellers are advised to take note of the following precautions:

• Contact with live or slaughtered pigs should be avoided in Sichuan province; this includes pig farms and live animal markets.
• Pork should be thoroughly cooked; WHO recommends that an internal temperature of 70ºC is achieved. Raw and undercooked meat should be avoided.
• Travellers who may be exposed to pork either occupationally or through cooking, should cover open wounds with a dressing and/or gloves and ensure thorough hand washing/cleaning of utensils.  

References

1. World Health Organization. Outbreak Associated with Streptococcus suis in pigs in China. 3 August 2005. http://www.who.int/csr/don/2005_08_03/en/index.html

Links

WHO Fact sheet on Streptococcus suis: http://www.wpro.who.int/media_centre/fact_sheets/

fs_20050802.htm