The researchers monitored drain water near Covid-19 isolation centres instead of treatment plants
Researchers from Noakhali Science and Technology University (NSTU) and North South University (NSU) have detected traces of the SARS-CoV-2 RNA in wastewater samples collected in July.
The first confirmed Covid-19 infection case in Bangladesh was recorded on 8 March.
The NSTU team led by Prof Firoz Ahmed, chairman of Department of Microbiology at NSTU, made the first and successful attempt to detect SARS-CoV-2 virus’ genetic material from sewage water samples in the country.
They collected 16 specimens between July 10 and August 29, from the drainage, sewage, and toilets near Shaheed Bhulu Stadium Isolation Centre for Covid-19 patients in Noakhali.
The team successfully detected several genes including “ORF1ab” and “N protein genes” from the sewage water samples.
Researchers said while the wastewater surveillance of Covid-19 has been focused on wastewater treatment plants around the world, they opted for drain water monitoring in the vicinity of the isolation centres for this research, which is the first of its kind.
“It felt amazing to detect the first Covid-19 tracing of genetic load in the vicinity of the isolation centres that had a constant number of 200 Covid-19 patients. It has been the key factor of the research as most of the studies reported worldwide have either reported total infected people in the city or country,” Firoz said.
“However, the critical observation has been the temporal variation where small drains showed easing of genetic load; the bigger canal and main sewer in the city exhibited temporal accumulation of SARS-CoV-2 RNA,” he added.
On the other hand, the distance of sampling location in metres appeared to be insignificant from the perspective of wastewater surveillance of Covid-19.
Researchers from other countries also traced Covid-19 in sewage water
According to virologists, the second wave of Covid-19 already started since July in some European countries and the virus will hit hard during winter.
Researchers in Spain, France, Netherlands, the United States, Australia, and India also found evidence of coronavirus in sewage water.
According to renowned virologist and former vice-chancellor of Bangabandhu Sheikh Mujibur Rahman Medical University (BSMMU) Prof Nazrul Islam: “The presence of Covid-19 in the gastro intestine system is internationally recognized, therefore, the method developed by the team to identify the presence of Covid-19 in the sewage water could serve as a tool to prevent the future spread of the disease.
“The presence of Covid-19 in sewage water indicates the presence of Covid-19 in an area despite no detection of actual patients in that area,” he added.
Prof Nazrul considered the initiative of the group as a remarkable achievement in developing an effective wastewater surveillance system in Bangladesh.
"Wastewater is an important source to monitor the presence and progress of the infection because the virus leaves the body of not only those who are symptomatic but also asymptomatic individuals through excretion," NSTU Prof Firoz also said.
“Our findings effectively substantiate the ability of wastewater surveillance to enormously supplement testing individuals who are infected or incubating that virus which causes Covid-19.”
The NSTU research team included Prof Newaz Mohammed Bahadur, Foysal Hossen, Shahadat Hossain, Aminul Islam, Main Uddin, and Md Nur Islam.
‘Policymakers can take effective measures to combat Covid-19’
Another research led by Prof Jakariya from the Environmental Science and Management Department at NSU said: “In most of the countries the surveillance was carried out in wastewater discharges while the present study focused on surveillance of SARS-CoV-2 near the Covid-19 isolation centres.
“The study is very unique and the identification of viral genetic materials in different distances from the isolation centres will provide information on the transmission potential of the virus and help policymakers to take effective measures to combat Covid-19.”
Dr Muhammad Maqsud Hossain, director at NSU Genome Research Institut,e while speaking to Dhaka Tribune said: “This finding will help us to develop methods to accurately measure quantities of SARS-CoV-2 in wastewater utilizing genomic approaches.
“Such studies will also provide information on the type of viral strains that are circulating in our communities, and whether new strains are being introduced from different regions due to travel and contact.
“We are also aiming to integrate the wastewater concentration and strain-level data with diagnostic testing and other public health data to provide a more complete picture that can be used by health authorities and decision-makers,” Maqsud added.
NSU Life Science Dean Prof Hasan Mahmud Reza said: “The detection of SARS-CoV-2 in wastewater is very important to understand whether this virus still exists in a particular community or not. If they are detected, the necessary treatment of wastewater will be required to prevent their transmission to safeguard public health.”
The NSU research team included Prof Jakariya, Dr Maqsud ,and Prof Hasan Mahmud Reza.