Dr. Leonardo Afable, municipal health officer, said he found the cases "unusual" since there has been none in this town in the past four years.
He said the number of malaria cases so far reported in Barangays Cawag and Salapian seems to be the highest in local history.
Afable said Rosalinda Castillo, 10, a resident of Barangay Cawag, died of celebral malaria last weekend. Two of her younger sisters are also afflicted and confined at the James Gordon Hospital in Olongapo City.
He cited reports that 24 cases of suspected cerebral malaria were reported yesterday in Barangay Cawag, and eight others in Sitio Gala in Barangay Salapian. He described the two villages as "remote and mountainous areas."
Most of the victims were children, he said. He denied reports of other malaria cases in San Marcelino town.
Despite the growing number of malaria cases in the two barangays, Afable, however, said they have not yet reached epidemic proportions.
In endemic regions where transmission of malaria is high, Afable said the people have gradually developed immunity to the disease.
Until they have acquired such immunity, children and pregnant mothers, whose natural bodily defenses are reduced during pregnancy, are most vulnerable, he said.
Afable said the Cawag victims live in a resettlement site for those displaced by the 1991 eruption of Mt. Pinatubo, while those in Sitio Gala belong to families who were relocated from Sitio Agusuhin where their homes were demolished to pave the way for a giant Korean shipbuilding project.
Afable said the municipal health office has enough medicines for the malaria victims.
Meanwhile, health authorities are also closely monitoring the spread of malaria in a village in Tupi, South Cotabato where at least 24 cases have been reported. Of the victims, 13 are minors aged 13 to 16.
Aside from Barangay Palian, Dr. Conrado Braña, chief of the South Cotabato Integrated Provincial Hospital, said health workers are also monitoring malaria cases in six other villages - Bunaw, Kalkam, Crossing Rubber, Kablon, Bolol Mala, and Poblacion.
The Tupi municipal council has passed a resolution declaring a state of calamity.
Afable said malaria parasites are transmitted from one person to another by the female anopheline mosquito. While there are about 380 species of the anopheline mosquito, only 60 or so are able to transmit the parasite, he said.
Afable said symptoms include fever, shivering, pain in the joints, and headache, which quickly disappear once the malarial parasite is killed by anti-malarial drugs.
"Like all other mosquitoes, the anophelines breed in water and their sensitivity to insecticides is also highly variable. It is hard to control these mosquitoes, especially in remote, mountainous areas. We are in a tropical country which are favorable to malaria mosquitoes," he said.
Pointing out that anopheline mosquitoes usually bite at night, he advised the townsfolk to use mosquito nets when sleeping and avoid going to places near swamps or pools of water.
According to the US Center for Disease Control, about 300 million people worldwide are affected by malaria and between one and 1.5 million people die from it every year. Previously extremely widespread, malaria is now mainly confined to Africa, Asia and Latin America.
Afable said malaria can normally be treated at home with oral medications and fluids but severe cases require intravenous infusion of anti-malarial drugs. He advised victims to drink lots of fluids to avoid dehydration.
He said there are four main types of the disease, all spread via mosquitoes. In cerebral malaria, the infected red cells obstruct the blood vessels in the brain even as other vital organs could also be damaged, often leading to the death of the patient.
In areas where malaria is endemic, the World Health Organization recommends that treatment be started within 24 hours. In non-endemic areas, uncomplicated or severe cases should be kept under clinical observation if possible.
Malaria has been known to exist since ancient times when it was believed caused by "miasma" or bad air from swamps.
For 2,000 years in China, people used infusion of a plant known as qinghao, whose active ingredient, artemisinin, was only scientifically identified recently.
Quinine, the active ingredient in a bitter bark used by Peruvians in the 15th century, was first isolated by pharmacists as cure for malaria in 1820.
As early as 450 BC, Egyptians were known to have built tower-like structures where they slept out of reach of malarial mosquitoes while others slept under nets. — With Ramil Bajo