Singapore: A Sentinel For Southeast Asian Seafood Safety (VIDEO)

What we learnt from the unprecedented 2015 GBS outbreak and its implications for food safety in Southeast Asia.

AsianScientist (May 24, 2019) – By Swaine L. Chen, Timothy Barkham, Ruth N. Zadoks, and the SEA-BeaSt Consortium – In 2015, Singapore experienced its largest reported outbreak of Group B Streptococcus (GBS) infections. GBS is a bacterium that is known to cause severe infections (such as meningitis, an infection of the linings of the brain) in newborn babies and elderly patients. The Singapore GBS outbreak was unique because it affected a very different group of people.

At the time, Singapore saw several hundred cases of GBS infections in otherwise healthy adults. Doctors in the local hospitals teamed up with the Ministry of Health, the National Environmental Agency, and the Agri-Food and Veterinary Authority. They quickly discovered that many of the patients had reported eating the raw yu sheng (魚生) dish commonly served with Chinese-style rice porridge; sales of this dish were stopped and the outbreak was over within a week.



An outbreak like no other

Several lessons were learned from this unusual and remarkable GBS outbreak. First, GBS may be a foodborne disease, which is a completely new paradigm for GBS. Second, the GBS causing this outbreak (referred to as ST283) seemed to be only found in Southeast Asia. Just as humans differ from each other, GBS isolates are different but can be placed into ‘families’ such as ST283, and these are usually globally widespread. Third, safety assurance procedures for seafood need to include testing for GBS.

Since 2015, ongoing research has shown that ST283 GBS has been causing invasive infections in adults in Singapore since at least 1998, and in Hong Kong since 1995. In Thailand and Vietnam, ST283 was found in farmed fish. These data raise two serious questions: Is ST283 GBS causing foodborne disease throughout all of Southeast Asia (SEA), and what is the role of farmed seafood products?

Over 99 percent of the SEA population live in low and middle income countries, where regional development is very rapid (four of the countries in SEA grew faster than China in 2017). SEA relies heavily on aquaculture as a driver of economic development and for provision of dietary protein, with demand increasing as the populations become more affluent. SEA is also unique in that many local cultural customs include consumption of raw or incompletely cooked seafood products. The discovery of foodborne GBS as a major infection risk thus links economic development, food security, food safety, import-export regulations and public health.


Hunting ST283 across the region

To answer whether ST283 GBS is causing foodborne disease throughout SEA, we need to collect data (about infections) and samples (bacteria from fish and humans) across the region. Each country in SEA has a different organization of hospital records, public health surveillance, aquaculture characteristics and cultural food preferences.

Associate Professor Swaine Chen of the Genome Institute of Singapore presenting data about GBS infections across Asia. Credit: Mohammad Noor Amal Azmai/Universiti Putra Malaysia.

Support for this work was obtained from the UK-based Global Challenges Research Fund, under the name ‘Southeast Asian Group B Streptococcus – Creating a network to address the regional threat to public health and aquaculture’ or SEA-BeaST. This network is led by an epidemiologist with expertise in patterns of bacteria transmission between animals and humans (Ruth Zadoks), a genomic and molecular microbiologist with expertise in tracking infection transmission and outbreaks (Swaine Chen), and a clinical microbiologist who was involved in the earliest stages of identifying and resolving the 2015 GBS outbreak (Tim Barkham).

The funding enabled us to host a workshop event at the Agency for Science, Technology and Research’s Genome Institute of Singapore, which took place on December 12-13, 2018. Representatives from both the medical and aquaculture sectors attended from six countries in the region, namely Singapore, Malaysia, Thailand, Vietnam, Cambodia and Lao PDR. Collaboration between experts from these two sectors is unique; it embodies the One Health paradigm, which is the notion that human, animal and environmental health are interconnected and cannot be fully understood in isolation.


Implications for aquaculture

Representatives from local hospitals, the Ministry of Health, the National Environment Agency, and the Agri-Food and Veterinary Authority in Singapore also attended, together representing the agencies that would investigate every step of a potential foodborne infection in Singapore, from port to plate to person.

In addition, representatives from the Food and Agricultural Organization of the United Nations and WorldFish (a non-profit research organization) joined the meeting. These groups have strong mandates to improve food security and safety and promote sustainable economic development in low and middle income countries like those in Southeast Asia.

The workshop covered the ongoing work subsequent to the 2015 Singapore outbreak, which set the stage for the primary question of how widespread foodborne GBS is in SEA. To address this question, participants from SEA and the UK outlined the current state of aquaculture and the impact of GBS on public health in the region.

There was an overwhelmingly common theme for all countries in Southeast Asia: aquaculture production is booming, and GBS infections are a significant threat to fish farming and food safety.

In fish, treatment options are currently limited; culling of potentially infected fish is not uncommon. There was also a consistent picture from the human health point of view: We have only sporadic if any data on GBS infections in humans in the region. The limited data we do have indicates that foodborne GBS may indeed cause the majority of GBS infections in SEA, as illustrated poignantly by a recent case of blood infections caused by GBS associated with raw fish in two visitors to Laos PDR, which sets the region apart from the rest of the world. Thus, control of GBS is in the interest of economics and food security as much as it is in the interest of public health.

Asian Scientist Magazine is an award-winning science and technology magazine that highlights R&D news stories from Asia to a global audience. The magazine is published by Singapore-headquartered Wildtype Media Group.

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