The ministry's bird flu screening system, in which state hospitals and other health care facilities screen their patients, might not cover blue-collar workers used to buying drugs at pharmacies instead of visiting doctors, said caretaker Public Health Minister Pinij Charusombat on Friday.

Pinij said that the nation's drugstores are places that can most easily check regarding the sickness of people, as many people when feeling unwell still prefer self-prescribing drugs for their own treatment to visiting a doctor or hospital.

"Pharmacists at the drugstores must ask for details about each patient who buys drugs. If they are found to have contacted sick or dead poultry or live in areas where a large number of fowls died of unknown causes, the pharmacists will recommend the patients to meet the doctor immediately," he said.

One reason for the increasing number of patients who are being included in the bird flu watchlist each day is because the country is entering the rainy season, he said.

"A lot of people catch the flu from the change of weather. Meanwhile, there is a seasonal outbreak of dengue fever. The symptoms of influenza, dengue fever, and bird flu are similar," Pinij said, "so the authorities have to implement strict measures to monitor the bird flu epidemic."