The number of Group B Streptococcus (GBS) infections have more than doubled in Singapore with some 355 cases reported year-to-date. The spike that started in July has been linked to the consumption of Chinese-style ready-to-eat (RTE) raw fish dishes and Type III GBS disease, specifically due to Sequence Type (ST) 283, according to Singapore health officials.
In addition, two fatalities have been linked to the infections.
At the time, The National Environment Agency (NEA) advised licensed retail food establishments to temporarily stop the sale of RTE raw fish dishes using Song fish (also known as Asian Bighead Carp) and Toman fish (also known as Snakehead fish). Now the number of GBS cases notified to MOH has decreased to the usual baseline of less than 5 per week and continued to remain low. The cause of these baseline infections remains unknown.
In the typical year in Singapore, 150 GBS cases are reported.
The investigation into the spike determined food handlers are unlikely to be the source of the bacteria as none of the stool samples tested positive for the Type III GBS ST283 strain.
Between August and October, the Agri-Food & Veterinary Authority of Singapore (AVA) and NEA tested fish samples from retail food establishments, wet markets, fresh produce section of supermarkets, and fishery ports. GBS was detected in 20.1% of these samples, and 4.1% were confirmed positive for Type III GBS ST283, which is the GBS strain associated with the consumption of Chinese-style RTE raw fish dishes.
The contamination of the fish could have occurred along the food supply chain.
The NEA says with the Christmas, New Year and Lunar New Year festive seasons near, members of the public who wish to purchase RTE raw fish are advised to do so from retail food establishments that have separate processes to handle RTE raw fish from other raw food meant for cooking, such as by having counters dedicated for the sale of RTE raw fish.