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 COVID-19 cases have led to unrest among some staff. Fifteen workers at a more than 5,000-person Amazon warehouse in Staten Island, New York, walked off the job on Monday, leading the company to fire one of them who was violating a paid quarantine.

Employees have also protested in other countries, including dozens of Amazon workers at a facility near Florence, Italy this week.

The following is a list of 19 company warehouses across the United States where one or more instances of COVID-19 have been reported. Amazon said in a statement 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. https://kfor.com/health/coronavirus/amazon-fulfillment-center-employee-tests-positive-for-covid-19

BROWNSTOWN, ROMULUS and SHELBY CHARTER TOWNSHIP, MICHIGAN - Three facilities near Detroit have had cases of the virus, including an Amazon sorting center https://www.clickondetroit.com/news/local/2020/03/24/amazon-confirms-employee-from-brownstown-sort-center-has-coronavirus-covid-19 and two Amazon https://www.detroitnews.com/story/news/local/wayne-county/2020/03/26/worker-amazon-center-romulus-diagnosed-covid-19/2915637001 fulfillment centers https://www.clickondetroit.com/news/local/2020/03/25/amazon-says-employee-from-shelby-township-fulfillment-center-has-coronavirus-covid-19, the company said in local media reports.

WALLINGFORD, CONNECTICUT - Amazon told local broadcaster WTNH last week https://www.wtnh.com/news/health/coronavirus/news-8-exclusive-employee-at-amazon-facility-in-wallingford-tests-positive-for-coronavirus that it was supporting a now-quarantined individual at its facility here who had the coronavirus. The site has stayed open, the report said.

LUZERNE COUNTY, PENNSYLVANIA: The company told Reuters that an employee at the facility had tested positive for the coronavirus.

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 told the Herald-News https://www.theherald-news.com/2020/03/25/joliet-amazon-fulfillment-center-worker-tests-positive-for-covid-19/aryelvf.

KATY AND HOUSTON, TEXAS - Amazon told local news that a management team member at a delivery station in the Katy area and another employee in the Ella, Houston area had tested positive for the disease.

JACKSONVILLE, FLORIDA - A fulfillment center employee tested positive for the virus, Amazon told local news https://www.news4jax.com/news/local/2020/03/24/jacksonville-amazon-employee-tests-positive-for-covid-19, 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".

CALEDONIA, MICHIGAN: The company told Reuters that an employee at the facility had tested positive for the coronavirus.

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. https://www.desertsun.com/story/news/health/2020/03/24/coronavirus-moreno-valley-amazon-warehouse-employee-tests-positive/5076295002/?fbclid=IwAR0O5XHNm5BobKQLgyIf7Pv5YJMHCZGlQ-Pzk96jSp4dptYH-XRrrcrBslA The warehouse is continuing operations, the report said.

STATEN ISLAND, NEW YORK - CNN has reported https://www.cnn.com/2020/03/25/tech/amazon-workers-coronavirus/index.html that a worker at a fulfillment center in New York City's least-populated borough had the virus.

EDISON, NEW JERSEY - Local news reported https://www.northjersey.com/story/news/coronavirus/2020/03/25/coronavirus-amazon-confirms-employee-edison-nj-tests-positive/5084582002 that an employee at the facility southwest of New York had tested positive for the virus.

INDIANAPOLIS, INDIANA - The company told Reuters that an employee at the facility had tested positive for the coronavirus.

KENT, WASHINGTON - Amazon told Reuters that at least one worker at the facility had tested positive for coronavirus.

EASTVALE, CALIFORNIA - The company said that at least one employee at the facility tested positive for the virus.

(Reporting by Jeffrey Dastin in San Francisco, Krystal Hu in New York, Munsif Vengattil, Kanishka Singh and Shubham Kalia in Bangalore; Editing by Leslie Adler, Maju Samuel and Shounak Dasgupta)