To discuss issues of sampling, testing and a standard operating procedure to communicate test results to communities
Research from past SARS epidemics has suggested fragments of the viruses from infected human beings are found in wastewater and sewage. These can be isolated and analysed to determine if there are infections in a particular geographic area. In India, this can be especially useful for herd surveillance in densely populated urban residential areas, and factory clusters, where individual testing and social distancing is improbable or impossible. Some such residential areas have community toilets (CTs) connected to a sewer line, or septic tank that is periodically emptied, from where samples can be obtained. This testing can be a sensitive tool to monitor circulation of the virus in a population.(1)
There exists no ‘Indian’ protocol to test sewage and develop an action plan based on the evidence to manage COVID-19 infections in densely populated urban residential areas or factory clusters. Currently, urban local bodies (ULBs) have no alternate means to detect COVID-19 infections other than mass testing/herd testing.
A few assumptions are necessary in this protocol:
I. The densely-populated urban residential areas or factory clusters need to have a sewer system. This can be a shallow, narrow-bore system. IHHLs, CTs and other toilets are connected to this
II. Industrial waste does not mix with sewage
III. There have been active/cured COVID-19 cases in the area; ideally there should active cases
IV. Laboratory facilities for testing exist and are accessible
There is some early research that suggests a method to collect, transport and test sewage samples. A paper from the KWR Water Research Institute, The Netherlands, is one such source. Additional sources will be identified and incorporated into a literature review. CNN reports that a MIT spin-off called Biobot and universities in New York have developed methods as well.(2)
To develop the protocol, it is possible to collaborate with organizations that have projects in densely-populated urban residential areas. Such areas can include chawls with about 50-80 families per building. Some are sewered but others have storage pits emptied by suction machines. Both are amenable to the proposed surveillance method. These areas are surrounded by factory clusters, usually comprising small and medium enterprises. While most industrial estates are sewered, it is unclear if the sewers carry both sewage and effluents.
For the sewered areas, the area needs to be mapped to determine collection points using Google Maps. A suitable ‘catchment’ population can be defined. Using the existing CT norms, this can be 30 people per sample collection point. The collection points need to be marked to develop a collection schedule. Successive samples will be taken in rotation to cover as much of the area as possible within a reasonable time frame. The collection norms will consider the feasibility, periodicity, capacity of the laboratory, capacity of the community and costs.
The collection and transport procedure recommended by KWR is defined in the paper. Biobot also suggests similar procedures. However, these will require modification for Indian temperatures and transport times, that impact sample degradation. The paper states the samples collected in The Netherlands were transported to laboratories on melting ice; a suitable substitute will have to be found for India.
The sampling rate must be statistically significant. The exact size will be determined from the size of the population/number of factories at a 95% confidence interval. From the areas, samples need to be transported to the nearest laboratory that meets bio-safety level 3 (BSL-3) norms. This will mean having a cold chain – ice or similar method – to reach the laboratory. That laboratory must be able to testi for COVID-19 fragments at high levels of dilution and contamination.
If a sample is found COVID-19+, a community outreach procedure will be required to inform and educate people about the findings and precautions required. This will include setting up a community level institution, messaging, finance and governance. These are crucial to the continued success of the project both in terms of collection and testing, and outreach with the people on the results.
Part A: Thematic e-discussion Questions:
1) What can be a protocol for surveillance and action at the ULB level for herd surveillance of COVID-19 through sewage testing for the virus? a. Specifically, we need a localised method of sample collection, transport and testing
The topic lead is Arunabha Majumder, Jadavpur University. This topic will open on 8th May and continue till about the 22nd May
2) What can be standard operating procedures for community outreach based on evidence?
The topic lead is Malini Reddy, Administrative Staff College of India
This topic will open on the 22nd and continue till 31st May
Discussion (3-4 weeks) starting from 8th May
Part B: Webinar or Roundtable
Research from past SARS epidemics has proved fragments of the viruses from infected human beings are found in wastewater and sewage. In the case of COVID-19, which is another such epidemic, these can be isolated and analysed to determine if there are infections in an area. In India, this testing can be a sensitive tool to monitor circulation of the virus in a population. We are attempting to develop an ‘Indian’ protocol to test sewage and an action plan to manage COVID-19 infections in densely populated urban residential areas.
The SuSanA India Chapter is conducting a thematic e-discussion on the topic examining issues of sampling and testing and a standard operating procedure to communicate test results to communities.
The SuSanA India Chapter, IRC, India Sanitation Coalition and WaterAid invite you to a webinar that will discuss points from the first part of the discussion. We invite you to provide suggestions for the second part, on how to communicate with communities. Speakers will also consider the health and safety of sanitation workers and the public health implications of COVID-19 sewage.
Some issues that may emerge from the first part of the Thematic e-discussion are:
i. Determining where samples should be collected from
ii. Collection frequency
iii. Collection method – grab, continuous, medium
iv. Storage and transport
v. Permissions from officials and communities for collection
vi. Where can samples be tested, costs and methods
vii. What are the technical considerations to develop a practical protocol?
The other aspect to be considered during the webinar is the health and safety of sanitation workers. Often employed by private contractors on behalf of housing societies and occasionally urban local bodies (ULBs), they are unprotected from sewage and its poisons. Their concerns can be brought out as part of the community engagement as this is a larger societal issue. What affects their health affects the health of the community.
Speakers can consider the public health implications of COVID-19 fragments in sewage. So far, research has not indicated these can cause infections. CPHEEO recommends disinfecting sewage with chlorine to kill any active viruses. There is another route to infections from community or public toilets that requires educating operators and users on disinfecting and hand-washing even more frequently.
In addition to the topic leads, to whom we need to speak, the following could be speakers:
- Malini Reddy. Topic – working with ULBs to adapt and adopt the protocol
- S Vishwanath - tbd
- V K Madhavan, WaterAid – issues and concerns of sanitation workers
- Dr Sundararaman, Global Coordinator, People’s Health Movement and former ED, National Health Systems Resource Centre. Topic – public health implications of testing COVID-19 in sewage
Moderator: Sunetra Lala, WASH Sector Leader, SNV
The main output will be a synthesis document summing up the responses from both the thematic discussion and the webinar.
Another output will be a testing protocol that will be validated by a small group of technical experts. This can be submitted to the Urban development ministry in Delhi and some state governments
(1) 2020. Gertjan Medema, Leo Heijnen, Goffe Elsinga and Ronald Italiaander; KWR Water Research Institute, Nieuwegein, The Netherlands. The Presence of SARS-Coronavirus-2 in sewage
Asia & Pacific
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