This was the initial result of the testing conducted on the water samples collected by the Department of Health (DOH) and the Manila Health Department from the Foreshore Area as part of an investigation into the incident.
"It is an outbreak most probably due to sewage contamination of the water lines but it has been already contained. The only affected area is Tondo. It has not spread to nearby areas," he said in a press briefing.
Dayrit added that he expects the investigation to be completed in seven to 10 days.
A total of 559 Foreshore residents have fallen ill to cholera and gastroenteritis since Oct. 23. They blamed the "foul-smelling and dirty" water supply in their area in the past two weeks for the outbreak.
But Rafael Alunan III, president of Maynilad Water Services Inc., said that leaking pipes, illegal connections and illegal use of booster pumps are rampant in the Foreshore Area and this likely caused the contamination of water supply there.
Alunan added that Maynilad had already disconnected 58 illegal connections and repaired 76 leaking pipes in Foreshore since last week.
He claimed that the water pipelines in the Tondo area were old because they were installed by the National Housing Authority 30 years ago.
"Foreshore was developed from a garbage dump 30 years ago by the NHA. It’s the NHA that should shoulder the replacement of the pipes," he said.
But Dayrit admitted that the disease outbreak in Tondo was bound to happen if the presence of the leaking pipes, booster pumps and illegal connections are taken into consideration.
"That kind of environment makes it conducive for (disease outbreak). With the illegal connections, booster pumps and leaking pipes, it’s an epidemic waiting to happen," he added.
The human waste that seeped into the pipelines is believed to have come from a defective septic tank in the area and caused by the unsanitary practices of some residents to discharge even in canals.
He said that contaminants seep into leaking water and go to the households. "If you tap into the water lines, the illegal connections usually pass through canals. And if you use booster pumps, event the contaminants are sucked in through the leaks."
"Tondo residents are advised to make sure that their water smells of chlorine to make sure that it was chlorinated and safe for household use. Or to boil their drinking water to kill the germs that cause gastroenteritis," Dayrit added.
But according to Dr. Jose Ramoncito Navarro, training officer of the Field Epidemiology Training Program (FETP), the investigation would not zero-in on the water supply. He is a member of the probe body that will look into the cause of the outbreak.
Navarro said that they would also check on the sanitary practices and personal hygiene of the Foreshore residents.
"We’ll identify the risk factors associated with the increasing cases of diarrhea there. We will not make recommendations not supported by data. We hope that the results of the investigation will help influence policy-making to prevent a repeat of similar incidents," he added.