More than 100 people have been affected by the disease since late last month, GMA News.TV reported. Heavy rains in the area might have aggravated the problem, health officials said.
Eric Tayag, with the health department's epidemiology center, said a health team visited the villages to conduct tests and to determine how the people were affected.
"We found out they get water from the stream and no chlorination is being done," Tayag was quoted as saying.
Philippines Health Secretary Francisco Duque III said the outbreak appeared to be on the wane since last week.
"It seems that's it's going down. We hope that this will continue," Duque said.