Unalaska has identified traces of COVID-19 in its wastewater, the city reported Friday.
That means enough people in the community now have the virus that public health officials can, for the first time, detect it through Unalaskans' sewage, according to Karie Holtermann, lab manager at the island's wastewater treatment plant, who spearheaded the local wastewater testing program.
"The viral load in the sample was very low and it was the first positive we have picked up since we began testing in July," Holtermann said. "So we must have reached a threshold of what the test is able to pick up. There were 12 reported cases on Dec. 4, but it is possible that there were more."
Monitoring sewage for traces of pathogens like COVID-19 allows health officials to survey entire communities to see if it's present and whether transmission is increasing or decreasing, said Holtermann.
She began testing local waste on a weekly basis over the summer, and says samples she took on Dec. 2 and 3 tested positive for COVID-19. She took the samples from the wastewater plant's influent, where all of Unalaska's waste comes to.
"It was essentially a COVID test for all of Unalaska," she said.
At the time of the testing, there were active cases of the virus on the island, the city said in a statement.
"So it is good to know the testing works and can detect the virus, even with relatively few cases on the island," the statement said.
Late last month, city officials confirmed two COVID-19 cases from community spread and said there was "potential widespread exposure" to the virus in the community.
Since then, an additional 55 people have tested positive for the virus in Unalaska, 33 of which were from two fishing vessels: the F/T Legacy and the F/T Enterprise.
Eight new cases of the coronavirus were reported on Friday, three of which are industry-related. The city said the other five are household members of individuals who previously tested positive for the virus.
To date, this marks 164 cases of the coronavirus in Unalaska, 21 of which are currently active.
