COVID-19 testing of plane, ship wastewater can be valuable contact tracing tool, study says

Melbourne, July 20: Testing of aircraft and cruise ship wastewater upon arriving at their destination for the genetic fragments of the novel coronavirus can be a valuable tool to prioritise clinical testing and contact tracing among disembarking passengers, according to a study.

The research, published in the Journal of Travel Medicine, noted that this tool could help as governments and transport industries develop plans to minimise transmission associated with resuming international travel.

"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," said Karen Andrews, Australia's Minister for Industry, Science and Technology.

In the study, scientists from The University of Queensland (UQ) and Australia's national science agency CSIRO worked with transport companies to test on-board wastewater from lavatories. They said rapidly pinpointing hotspots for COVID-19 will help people start to travel again.

"This could provide additional peace of mind to track and manage infection and play an important role in opening up long-haul flights or cruises resuming," said study co-author Jochen Mueller from UQ's Alliance for Environmental Health Sciences. According to the researchers, the test provides an early warning of infection, as the virus sheds in the stools of infected passengers even before they show symptoms. However, while the coronavirus genetic material, RNA, was detected in samples from both aircraft and cruise ship wastewater, the scientists said the concentrations were near the "assay limit of detection."

"The study indicates that surveillance of wastewater from large transport vessels with their own sanitation systems has potential as a complementary data source to prioritise clinical testing and contact tracing among disembarking passengers," the researchers wrote in the study.

Owing to the potential for false negatives by both wastewater testing and clinical swab testing, the researchers suggested that the two strategies could be employed together to "maximise the probability of detecting SARS-CoV-2 infections amongst passengers."

Lead author and CSIRO researcher Warish Ahmed said the virus fragments in the wastewater were unviable, making them non infectious. "The study indicates that surveillance of wastewater from large transport vessels with their own sanitation systems has potential as a parallel data source to prioritize clinical testing among disembarking passengers," Ahmed added.