Health authorities fear Sars may be starting to resurface in the community, after a 58-year-old woman who lives in Wong Tai Sin was diagnosed with the virus yesterday. Doctors are mystified by the infection of the woman, who has had no contact with known patients, nor made a recent visit to a hospital. The case could be the first untraceable infection since late April, when cases began to emerge at Sha Tin's Lek Yuen Estate. Director of Health Margaret Chan Fung Fu-chun said family members and the woman's doctor told government disease investigators they did not know how she got infected. 'At this point we would need to look for further evidence to substantiate that this could be a case arising from the community. It is too early to say so, but that is one possibility that we would not dismiss,' Dr Chan said. The woman, who is chronically ill, lives in Pak Fung House on Choi Wan Estate. She was one of two confirmed cases yesterday, bringing the total infections to 1,750. The second case, a 78-year-old woman, was confirmed in the North District Hospital. Dr Chan said the Wong Tai Sin woman was already in critical condition when diagnosed with Sars. The woman's family members have not been infected so far, the director said. 'We feel we still have to trace the source of the infection. It is quite unusual that all the other family members were okay,' she added. Two women, aged 59 and 90, died yesterday, taking the death toll to 286.