But this time was different: The fever refused to break and only burned hotter. Toni's cough worsened until it began choking him, and Suryoto realized he must get his son to a doctor. It's a decision he now wishes he had made sooner.
"His voice kept getting softer and softer until you could not hear anything," Suryoto, recalled. "He kept saying, 'hard to breathe."'
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The child died just after arriving at the hospital. Suryoto said he can still remember Toni gasping for air and struggling to whisper, "father, father."
He and his wife, Suryani, later learned that bird flu had likely ravaged their child's lungs, but that will never be known for sure because he was buried in a graveyard near their village on the outskirts of Indonesia's capital, Jakarta, before samples could be taken.
There was no time to grieve. Suryoto's 7-year-old daughter was also burning up with fever after being taken to a local hospital. Again, the distraught parents were too late. Their little girl died Thursday evening, three days after her brother. Local tests have found she was infected with the H5N1 bird flu virus.
Suryoto, 46, and Suryani, 34, who like many Indonesians use only one name, are left asking how and why? Both had heard a little about bird flu on television, but never dreamed it was in their village or capable of potentially killing two of their children in the same week.
"It's really hit me. I never imagined that this could happen to us" said Suryani, standing with her surviving 4-year-old son on their small concrete porch. "I thought it was only a regular flu."
Specimens taken from the girl have been sent to a World Health Organization-approved laboratory in Hong Kong for confirmation. If positive, it will be another case in a spate of recent deaths gripping Indonesia, which is on pace to become the world's hardest-hit country.
There was an average of one bird flu death every 2 1/2 days last month, bringing Indonesia's toll to 37, only six behind worst-hit Vietnam. The World Health Organization confirmed the latest death, a 15-year-old boy, on Sunday, Indonesian health officials said.
Experts have been concerned about six of seven family members who died in May on the island of Sumatra after testing positive for the virus. An eighth relative was buried before samples could be taken, but WHO considers her part of the cluster — the largest ever reported.
Scientists have not been able to link the infected relatives to contact with sick birds and believe limited human-to-human transmission may have occurred. However, the virus has not mutated and no one outside the family has fallen ill.
Indonesia has been criticized for not working harder to fight bird flu, which is entrenched in the sprawling archipelago of 220 million people. Many local governments have refused to carry out mass poultry slaughters in infected areas and vaccinations have been sporadic at best.
Such measures have helped other hard-hit countries like Vietnam and Thailand to curb outbreaks. Indonesia, however, has a decentralized government where money and the power to make decisions resides with local officials.
In Kedaung village, about 45 kilometers (28 miles) outside Jakarta, dozens of children run barefoot and ride bikes through a soccer field just outside the dead children's house.
It's a typical scene in Southeast Asia — kids playing carelessly amid chickens, goats, sheep and cats in a field littered with garbage and burning trash heaps.
Suryoto points across the grassy field to a small building where a slaughterhouse is run. He said his daughter, Yohana, and her brother played in the rain barefoot near the building about a week before falling ill and likely stepped on chicken remains and droppings.
He never realized such behavior could put them at risk of bird flu.
"I knew nothing about the symptoms of bird flu ... I thought this bird flu came from Thailand," said the slight man who works as a local bus driver. "The disease is very fast — it kills very fast. I was in a state of confusion. They had fever, and I could feel their hearts beating so fast. I was afraid."
Neighbors fear their kids could be next to fall ill and have banned them from going near the slaughterhouse.
After the deaths, Zubaedah, 46, a mother of six, said she sold all 20 of her backyard chickens. None appeared ill, but she wasn't taking any chances.
"We are all very worried," she said, as a rooster scratched the ground nearby. "We never dreamed that such an illness would arrive in our village."