Hong Kong now has 61 confirmed cases of novel coronavirus, according to the city's health department.
The latest patient is a 32-year-old woman from the Philippines who works in Hong Kong as a domestic helper, Dr. Chuang Shuk-kwan of the Center for Health Protection said at a news conference on Tuesday.
Her employer was the 52nd person to become infected with the virus in the city, Chaung added.
The woman started to have a cough and fever on February 2 but got better after self-medicating and didn't go to the doctor, Chaung said.
Her employer tested positive on Thursday, February 13. The domestic helper first tested negative, but remained in hospital for monitoring. She tested positive on Monday.
Chaung warned initial tests may not pick up enough of the virus, causing people to test negative even when infected. This is why a patient is tested again if their condition deteriorates or they have had close contact with confirmed cases.
Health officials are contacting about a dozen friends of the 61st case who gathered with her outside City Hall on February 9.
Hong Kong is home to 385,000 foreign domestic workers, from countries including the Philippines, Malaysia and Indonesia. They are the economic backbone of the city, enabling more mothers to work and generating $12.6 billion to Hong Kong's economy each year, according to one report.