Previous reports have shown that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes the coronavirus disease (COVID-19), has been found in untreated wastewater. While the data is limited, there are no reported cases of a person becoming infected with the virus due to exposure to contaminated water.
Now, a team of researchers from Australia's national science agency, the CSIRO, and the University of Queensland have found genetic fragments of SARS-CoV-2 after testing aircraft and cruise ship wastewater once they reached their destinations.
Published in the Journal of Travel Medicine, the study highlights the importance of using wastewater as a means to determine if infected passengers are coming into a country via ship or airplane.
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New testing method for passengers
The researchers said testing the wastewater could be an additional data source for testing and managing passengers after disembarkation. The viral fragments are not infectious but may determine that there are infected people on board the ship or plane, which can narrow down the testing of passengers.
Many people infected with the coronavirus are asymptomatic, which means that they are unaware that they harbor the virus. Testing can help determine those who may be exposed and infected with the potentially deadly virus.
"The study indicates that surveillance of wastewater from large transport vessels with their sanitation systems has potential as a complementary data source to prioritize clinical testing and contact tracing among disembarking passengers," the researchers concluded.
"Importantly, sampling methods and molecular assays must be further optimized to maximize sensitivity. The potential for false negatives by both wastewater testing and clinical swab testing suggests that the two strategies could be employed together to maximize the probability of detecting SARS-CoV-2 infections amongst passengers," they added.
Testing wastewater can be a valuable tool to determine if any of the passengers harbor the novel coronavirus, which may create another cluster of infections. The new test can determine if any of the incoming passengers are infected with the virus, who may transmit it to others.
"Our science and research communities are among our greatest assets in our efforts to not only overcome this pandemic but also to assist in the economic recovery from COVID-19," Karen Andrews, Minister for Industry, Science and Technology, said.
"The ability to test wastewater from planes and cruise ships is another piece of the puzzle as we look to the future of travel and keeping Australians safe," she added.
To arrive at their findings, the research team collected and tested airline and cruise ship wastewater samples for SARS-CoV-2 RNA using two virus concentration methods – the adsorption-extraction by electronegative membrane and ultrafiltration by Amicon. They also utilized give assays using reverse-transcriptase quantitative polymerase chain reaction (RT-qPCR) and RT-droplet digital PCR.
The team has found SARS-CoV-2 RNA in samples from both aircraft and cruise ship wastewater.
Finding COVID-19 hotspots
Finding hotspots for COVID-19 can help protect the country's residents since many areas across the globe are now opening their borders. Amid the coronavirus pandemic, many countries have started lifting lockdown measures to save the economy and help people go back to work. With this, air and sea travel will also commence.
Health experts say that it is vital to determine COVID-19 hotspots, which pertain to areas or situations where the virus may rapidly spread. These include transport vehicles, including cruise ships and aircraft.
"Responding to a pandemic is not just about the race for a vaccine, Australian science is supporting our economic recovery by delivering for partners like Qantas. Our relationship with air travel goes back to the 60s, and today our unique coatings already protect aircraft. Hence, it's great to be trusted to keep Australia flying while helping to stay ahead of any potential new outbreaks," Larry Marshall, CSIRO Chief Executive, said in a statement.
He added that determining the hotspots for virus spread will help keep all Australians safe as people start to travel again.