A 49 year-old woman has become the Philippines' first fatality linked to swine flu, health authorities said Monday.
The woman died from "acute myocardial infarction" according to the health department.
She had been suffering from heart and liver ailments for some time, and the department said in a statement that her infection with the influenza A(H1N1) virus had worsened her condition.
The woman's case had gone undetected until a doctor visited her in her home when she was already in critical condition, the department said, without giving additional details.
Authorities are now checking if the woman had travelled abroad or shared her living quarters with someone who had gone abroad.
The Philippines has reported 428 cases of influenza A(H1N1) but most of them have since recovered.