Coronavirus pandemic: Using human faeces to track Covid-19
Almost all recently reported cases are due to a severe outbreak in dormitories housing lowly paid foreign workers, mostly from India, Bangladesh, and China.Updated: Jun 22, 2020 13:31 IST
Although Singapore is still averaging over 200 new COVID-19 cases per day for the past week, the government surprised residents by announcing an earlier than expected start of phase two of re-opening the economy.
Singapore has now close to 42,000 cases - a large number for a small country of 5.7 million people but this is due to extensive testing especially in migrant workers dormitories. Almost all recently reported cases are due to a severe outbreak in dormitories housing lowly paid foreign workers, mostly from India, Bangladesh, and China. Singapore has vowed to ensure the health of each one of the 325,000 foreign workers who mostly work in tough jobs that locals shy away from in construction, shipyards, waste management and landscaping.
As of June 15, the ministry of manpower reported that 75,000 workers living in dormitories have been cleared of the virus.
Singapore started its lockdown relatively late on April 7 after handling the initial outbreak rather well. It started seeing a spike in cases in late March and decided that if nothing was done, the coronavirus would spread into the communities at a rate the healthcare system and isolation facilities would not be able to cope with. At its height, hotels, university hostels as well as two of the largest exhibition complexes on the island - Changi Expo and Singapore Expo were utilised as isolation centres.
Since then, as of the end of last week, 34,224 infected people have recovered and have been discharged from hospitals and community isolation facilities. There are currently 7,398 people isolated and cared for at community facilities, and 184 confirmed cases still in hospital. Of these only one is currently in intensive care with the rest are in stable condition. 26 have succumbed to the virus.
In phase one of the re-opening which started on June 1, a small number of businesses could open. For example, hairdressers, dental services, traditional Chinese medicine clinics, some renovation and construction work and some government services. About 20 per cent of students returned to school.
As of Friday, last week, almost all economic activity resumed with the start of phase two although strict safe distancing and contract tracing measures have to be adhered to. Retails outlets and restaurants could open but with the latter allowed to have dine-in customers with no more than 5 in a group. Parks, sports and recreational facilities, religious services for no more than 50 at a time are also permitted. All students will also gradually return to school.
However, on the first day of re-opening, large crowds were seen at malls and dining establishments. It was like water gushing out of a broken dam. In just one of many instances of over-crowding, hordes flocked to Holland Village, a suburban shopping and entertainment area especially popular among expatriates.
A restaurant, “British Indian Curry Hut”, was forced by authorities to close for a week for failing to implement safe distancing measures when uncontrolled crowds gathered at its entrance. This is despite the restaurant’s General Manager arguing that most of those outside were not his customers.
Besides safe distancing and contract tracing, Singapore continues to conduct clinical tests among the population as well as conduct surveillance to monitor the cases in the community.
One new and fascinating way of surveillance being introduced is the testing human waste and wastewater for signs of the pathogen.
In a joint press statement issued last week, the National Environment Agency (NEA), National Water Agency PUB and Home Team Science and Technology Agency (HTX), announced a pilot surveillance programme to screen wastewater samples for the COVID-19 virus.
With the help from scientists from local universities as well as Singapore-Massachusetts Institute of Technology Alliance for Research and Technology (SMART) a sampling and testing methodology was developed. The initial efforts were focused on assessing the situation at and reducing the transmission of COVID-19 in migrant workers’ dormitories. Samples were taken from the sewerage systems in the dormitories to screen for genetic material from the virus. The study showed that those with mild or no symptoms can shed the virus in their stools.
Wastewater testing is not the sole means of detecting the virus in the dormitories but complemented by swab tests on individuals. Together, they can aid decisions with regards to whether workers from a particular dormitory are healthy and can return to work.
The result of the trials at the dormitories so far has shown that the concentration of virus material is related to the prevalence of the virus in the dormitories. It has demonstrated the utility of wastewater testing as a warning system for the presence of COVID-19 cases and the trending of COVID-19 concentration over time can determine if infection control measures taken have been effective.
In future wastewater samples can also capture information on a cross-section of the community, which allows for monitoring of large groups. It also allows for more targeted clinical testing.
Tracking the spread of COVID-19 through wastewater and sewage is not entirely new. Early in the pandemic, researchers in China, Italy, France, Netherlands, and Australia have reported finding traces of the virus in wastewater in toilets and sewers.
Access to this type of data could underpin a surveillance programme to identify areas where there is evidence of COVID-19 outbreaks without requiring the testing of all individuals. It is also relatively inexpensive and could be useful for countries, for example in Africa, that do not have the technical or logistical means to test carriers of the virus.
Ultimately, regardless of the sophistication and extent of testing, a vaccine will be required for life to return to the old normal - how it was before the COVID-19 outbreak. In the meantime, in the new normal, wearing face coverings, contact tracing, social distancing, and very restrictive air travel will be the norm.
(This story has been published from a wire agency feed without modifications to the text. Only the headline has been changed.)