This transmission electron microscope image shows SARS-CoV-2, the virus that causes COVID-19, isolated from a patient in the U.S. Virus particles (round gold objects) are shown emerging from the surface of cells cultured in the lab. The spikes on the outer edge of the virus particles give coronaviruses their name, crown-like. (Courtesy National Institute of Allergy and Infectious Diseases – Rocky Mountain Laboratories)

The number of Ketchikan residents testing positive for coronavirus has risen to 13. That’s following Saturday’s announcement of an additional case that authorities say was not travel-related.

It remains unclear how the person became infected. Officials in Ketchikan haven’t said whether the person was in contact with others known to be infected with the virus but said state public health officials are investigating.

Statewide, there are 114 confirmed COVID-19 cases as of Sunday evening. At least seven people have been hospitalized; three Alaskans have died from the disease including one in Washington state.