Members of the public are advised to exercise caution when consuming ready-to-eat (RTE) raw fish, according to a joint press release by the Ministry of Health (MOH) and the Singapore Food Agency (SFA) on Sunday (Aug. 30).

Both MOH and SFA are currently investigating a recent uptrend in the number of Group B Streptococcus (GBS) cases, with 50 GBS cases reported from public hospitals in July 2020.

This is up from an average of 25 GBS cases per month from January to to June 20.

Most GBS cases have been discharged

In addition, further laboratory investigations indicated that 18 of the cases reported in July were GBS Type III ST 283.

This compares with an average of four cases per month from April to June 2020.

Consumption of raw fish is strongly associated with the invasive sequence type 283 infections, according to a study conducted in 2016.

GBS is a common bacterium that can be found in the human gut and urinary tract of about 15-30 per cent of adults, MOH said.

While it normally does not cause damage, it may occasionally cause invasive infections of the skin, joints, heart and brain.

The study added that it can also lead to urinary tract infections, bacteremia, and meningitis in adults.

Most GBS infections are treatable with antibiotics.

The majority of the cases with GBS Type III ST283 were those aged 65 and above, and most have since been discharged and have recovered from the infection.

However, one case has passed away due to an unrelated cause.

According to the press release, both MOH and SFA are currently collecting information on the affected individuals' food history, and conducting field investigations at various locations, in order to determine possible sources of GBS in these cases.

Use of freshwater fish for raw fish dishes banned since 2015

Based on SFA's routine sampling and testing of fish samples for GBS between May 2019 and August 2020, the presence of ST283 has not been detected.

SFA also conducted inspects at food stalls visited by recent cases, and found that none of the stalls sold any RTE raw fish dishes.

The use of freshwater fish for sale of RTE raw fish dishes has been banned since December 2015, and the SFA will be issuing reminders to food establishments to adhere to the ban.

Food establishments selling RTE raw fish are also reminded to ensure good hygiene practices and proper handling of the RTE raw fish.

Vulnerable groups of people advised to avoid raw food

GBS infections have previously been associated with the consumption of raw freshwater fish, as raw food is likely to contain more bacteria compared to well-cooked food.

Vulnerable groups of people, especially young children, pregnant women, elderly persons or people with chronic illnesses such as diabetes may be more susceptible to GBS, and are advised to avoid the consumption of raw food.

Individuals can reduce their risk of GBS infection by thoroughly cooking food, washing hands and kitchen utensils thoroughly before handling food, and using separate sets of knives and cutting boards for raw and cooked food.

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