(Reuters) - Amazon.com Inc AMZN.O is at the front line of responding to outbreaks of the novel coronavirus in the United States, delivering essential goods while about half the population faces government stay-at-home orders.

FILE PHOTO: Amazon boxes are seen stacked for delivery in the Manhattan borough of New York City, January 29, 2016. REUTERS/Mike Segar

However, news reports that a handful out of Amazon’s hundreds of thousands of U.S. warehouse workers have contracted the virus raise the potential of future site closures and operational disruptions at the world’s largest online retailer.

The following is a list of 13 company warehouses across the United States where one or more instances of COVID-19 have been reported. Amazon, which did not respond to Reuters requests that it confirm all the cases, said in a statement that it has taken preventive action and that workers’ health and safety is its top priority.

According to logistics consultancy MWPVL International Inc, Amazon has 519 facilities in its U.S. distribution infrastructure -- including fulfillment centers, delivery stations and warehouses.

QUEENS, NEW YORK - On March 19, Amazon said it was temporarily closing delivery station DBK1 after an associate there tested positive for the virus. It was the first known case at an Amazon warehouse in the United States.

SHEPHERDSVILLE, KENTUCKY - Amazon said it shut a warehouse until April 1 at the direction of the state’s governor. Several workers at the site, known as SDF9, had contracted COVID-19. The facility handles apparel and footwear, according to MWPVL.

OKLAHOMA CITY, OKLAHOMA - A worker at Amazon's OKC1 fulfillment center said until he had tested positive, he needed to keep working to pay his bills. "I hope I didn't spread it," he told local television station News 4. here

BROWNSTOWN, ROMULUS and SHELBY CHARTER TOWNSHIP, MICHIGAN - Three facilities near Detroit have had cases of the virus, including an Amazon sortation center here and two Amazon here fulfillment centers here, the company said in local media reports.

WALLINGFORD, CONNECTICUT - Amazon told local broadcaster WTNH last week here that it was supporting a now-quarantined individual at its facility here who had the coronavirus. The site has stayed open, the report said.

JOILET, ILLINOIS - A worker, who was last at a fulfillment center in this city southwest of Chicago on March 18 and now is in quarantine, caught the virus, Amazon said to the Herald-News. here

KATY, TEXAS - Amazon told local news abc13.com/6044787 that a management team member at a delivery station outside Houston had tested positive for the disease.

JACKSONVILLE, FLORIDA - A fulfillment center employee tested positive for the virus, Amazon told local news here, which quoted an anonymous worker as saying the person was "upset, angry, scared -- basically in fear for my safety, in my own immediate (family's) safety."

MORENO VALLEY, CALIFORNIA - Amazon notified employees at its "ONT8" fulfillment center that a worker had contracted COVID-19. Last at the facility on March 18, the person has since received medical care and has gone into quarantine, the Desert Sun reported. here The warehouse is continuing operations, the report said.

STATEN ISLAND, NEW YORK - CNN has reported here that a worker at a fulfillment center in New York City's least-populated borough had the virus.

EDISON, NEW JERSEY - Local news reported here that an employee at the facility southwest of New York had tested positive for the virus.