MANILA, Philippines?The number of persons suspected with the A(H1N1) flu virus has shot up to 38 from 23 as of Monday after the Department of Health (DoH) received reports of suspected cases from private hospitals.

The DoH, however, stressed that only one patient?a 4-year-old girl from Naga City?was still under observation pending the results of her laboratory tests.

Thirty-seven of the so-called cases under observation since May 1 have already tested negative for the deadly swine flu virus, and so far 35 of them have been discharged from the hospital. The remaining two still have to be discharged.

According to the DoH, the Naga City girl arrived on May 9 from the United States, which has the highest number of confirmed swine flu cases.

Health Undersecretary Mario Villaverde said the girl was brought to the Research Institute for Tropical Medicine (RITM) in Alabang, Muntinlupa, on May 11 for treatment and testing for the virus.

But Villaverde said the jump in the number of suspected cases was not a cause for alarm.

He said the government merely updated its record of cases after private hospitals reported the suspected swine flu cases they had received since May 1.

Villaverde, however, said the country remains free of the virus, which has already spread to 33 countries.

The Philippines has received about 300 testing kits from the World Health Organization. With these testing kits, the country?s pathology analysts can readily check if a specimen taken from a patient with flu would turn up the novel A(H1N1) virus.

In Naga City, health authorities have stepped up the monitoring of possible A(H1N1) cases after the girl who came from San Diego, California, showed flu-like symptoms upon her arrival in the Philippines.

Dr. Vito Borja, city health officer, said the patient was handled by two physicians who volunteered to quarantine themselves in their homes as a precautionary measure.

Borja declined to reveal the place in Naga where the patient stayed upon arrival to prevent panic among the public.

He said the patient would be further tested at the RITM in Alabang. Her parents were also quarantined with her in the hospital. They were all supposed to attend a wedding in Naga.

The regional health office has already started contact-tracing and surveillance on persons who were in contact with the girl, Borja said.

But he warned people to avoid self-medication, especially since the medicine Tamiflu could be bought over the counter in drugstores.

A patient who takes Tamilflu even without the A(H1N1) virus may develop resistance to the medicine, Borja said.

Dr. Nestor Santiago, regional health director, said the DoH, in cooperation with the city government, had already laid down plans for public health intervention to monitor the community where the patient had stayed upon her arrival.

?I also called on the immediate family members, the relatives and the hospital personnel who had contact with the child to self-quarantine to prevent the possible spread of the disease,? he added.

Santiago said that the provincial government had already allocated half a million pesos as a standby fund for contingency measures.

Albay Gov. Joey Salceda has alerted three hospitals to set aside quarantine rooms in case a confirmed case of A(H1N1) emerges in the province.

These are Bicol Regional Training and Teaching Hospital in Legazpi City, Ziga Memorial District Hospital in Tabaco City and Josefina Duran Memorial District Hospital in Tuburan, Ligao City. With reports from Juan Escandor Jr., Jonas Cabiles Soltes and Rey Nasol, Inquirer Southern Luzon