MANILA, Philippines—The Department of Health remains on “heightened alert” to address the outbreak of the flood-borne disease leptospirosis not only in Metro Manila but also in other places ravaged by back-to-back typhoons in September.

Health Secretary Francisco Duque III said Wednesday that the outbreak in Marikina has already “passed,” but an outbreak has been declared in the towns of Aringay, Bauang and Naguillan in La Union.

Three towns in Pangasinan—Rosales, Mangaldan and Binmaley—were under observation for a possible outbreaks, he added.

“This is a heightened alert because the number of leptospirosis [cases] has tripled compared to the number of cases last year,” Duque said as he inspected evacuation centers in Muntinlupa and in Biñan, Laguna, with World Health Organization officials.

“We are heightening our surveillance system for leptospirosis and dengue all-year-round, and other diseases that put our people at risk especially where there is lack of sanitation and potable water,” he said, citing cholera, typhoid fever, diarrhea and pneumonia as diseases common in congested evacuation centers.

As of Oct. 27, the 15 so-called sentinel hospitals in Metro Manila reported 2,172 leptospirosis patients, including 167 who have died.

Last year the DOH reported 860 cases nationwide.

“This is really an abnormal situation where you have a substantial increase in leptospirosis cases,” Duque said.

The WHO said a four-person team made up of experts in leptospirosis control, epidemiology and clinical management of the disease have began their field mission.

Dr. Shin Young-soo, WHO regional director for the Western Pacific region which includes the Philippines, said the experts would determine the strain of leptospira bacteria causing the outbreak of an otherwise rare disease that is transmitted through exposure to floodwaters contaminated with the urine of rats or other animals.

“The experts are here, basically we are working in solidarity with the Philippine government and the Filipino people in this difficult time,” he said.

“But what I have found is the unique character of the Filipino people. They are never defeated and they always smile. I am sure in the future they will recover in this situation,” he added.

WHO country representative Dr. Soe Nyunt-U said the WHO has provided the DOH about $1 million worth of medical supplies, essential medicines and health kits for the evacuees.

“We are raising $3.6 million for sterile kits and health kits. But WHO is raising an over-all amount of $15 million for the whole health cluster efforts,” he said.