The communities, whose residents were reportedly afflicted by the disease, were Barangays 25 and 38 in Caloocan, and Barangay Longos in Malabon.
According to KPML head Rey Baltazar, some five children and adults in Caloocan were already admitted in hospitals.
Meanwhile, Arceli Binondo, one of the Barangay leaders in Longos, claimed that five more were afflicted with the disease in nearby Malabon.
Baltazar blamed the drinking water in the area for the spread of the dreaded disease.
Maynilad Water Services, Inc., which services Caloocan and Malabon, has already deployed its personnel to check the water in the two areas.
Jess Matubis, Maynilads assistant vice president for corporate affairs, said initial reports reaching his office disclosed that the water condition in the two areas were normal.
But he quickly noted that further tests will be conducted to verify and double check the information revealed by Baltazar and Binondo.
He said Maynilad is also coordinating with the city health department of Caloocan and Malabon to confirm the alleged cases of gastroenteritis.
"In cases like this, the one that should announce it should be the city health department. Although its their right to express their opinion, the authority to say that there is such incidence in certain areas should be the city health department so as not to create panic and fear among the people," Matubis told The Star.