(CNN) Twenty six more cases of locally-transmitted Zika virus have been confirmed in Singapore, the city-state's Ministry of Health (MOH) said late Tuesday.
With 56 cases confirmed Monday, the total number of Zika virus infections in Singapore has risen to 82.
Seven patients who are still symptomatic, and potentially infectious, are being treated at Tan Tock Seng Hospital, the MOH said Monday. The rest have fully recovered.
"They are not known to have traveled to Zika-affected areas recently, and are thus likely to have been infected in Singapore," a statement released by the ministry said.
The majority of the 82 reported cases are foreign construction workers. On Monday, the MOH finished testing all of the workers on the construction site who had shown symptoms of fever and rash. Workers staying in dormitories found in areas of concern were also screened.
There is no vaccine or specific medication to treat the mosquito-borne virus, which has been linked to serious birth defects.
Although all the cases were clustered in one neighborhood -- Aljunied Crescent -- the MOH warned the virus could spread further as some of the patients live or work in other parts of Singapore. Since August 29, the National Environment Agency in Singapore has screened roughly 5,000 premises out of an estimated 6,000 in the Aljunied Crescent neighborhood to check for mosquito breeding grounds. The agency has detected and destroyed 39 breeding habitats so far.
Singapore's first imported Zika case was reported in May after a man who visited Brazil began showing symptoms and was admitted to hospital.
First case of imported Zika confirmed in Singapore
The revelation of the locally-transmitted infections in Singapore are in addition to the 58 countries and territories where the Zika virus is circulating, according to the WHO and Centers for Disease Control.
Around the region, Indonesia, Thailand, Vietnam and the Philippines have "possible endemic transmission or evidence of local mosquito-borne Zika infections in 2016," the WHO said.
Nearby Hong Kong reported its first imported case last Thursday: a 38-year-old woman who visited the Caribbean in early August.
She subsequently developed joint pain and red eyes but has been without fever, the city's Centre for Health Protection said. She is in a stable condition and has been put under isolation at United Christian Hospital.
"In view of the recent first imported case in Hong Kong, we are facing risks of importation of cases," a CHP spokesman said. "All sectors should step up efforts on mosquito control and members of the public should use insect repellents to protect themselves, their families and the community.
The Zika virus has been linked to microcephaly, which causes unusually small heads and brain damage in children born to infected mothers. It is also linked to blindness, deafness, seizures and other congenital defects.