One week after the joint MOH/NEA/AVA statement, the Straits Times reported this morning that sales of “yu sheng” (raw fish) has plunged at porridge stalls, with some stalls opting not to sell the dish entirely, while others have shifted (back) to saltwater fish such as the ikan parang. Even these stalls are likely to have seen their business drop – my colleagues and I visited a popular porridge stall in Tiong Bahru during lunch one week day this week and were quite surprised to find how poorly patronised it was compared to before (the stall was still selling raw ikan parang – their staff took pains to explain to us that this was a saltwater fish and the problem was only with freshwater fish which they no longer sell). An unfortunate but predictable fallout from the more limited and narrow warning against selling (and eating) raw bighead carp and snakehead.

Screen grab showing the ST news headline on the drop in “yusheng” consumption.

Anecdotally, however, the number of severe GBS infections appears to have dropped around the island. There are still cases, but most of the ones associated with “yu sheng” consumption occurred in patients that had eaten the raw fish before the MOH/NEA/AVA advisory came out. Given that the “incubation period” of the outbreak GBS is up to two weeks, we should still expect some cases next week, followed by a return to near baseline of severe GBS cases. “Near baseline” because a significant minority of the cases of severe GBS infections in the recent past were not associated with “yu sheng” consumption – there may possibly be another minor unidentified source. It will never be zero severe GBS infections because there is after all a number of cases that occur “normally” in adult patients that are immunocompromised, etc. Correlation is not causation, of course, but it will be interesting to see the data and the results of the investigations when they are released or published.

Some people have asked what is this “song he” or bighead carp – here is a picture from Wikipedia commons.

Wikipedia Commons image of bighead carp (Hypophthalmichthys nobilis).