MANILA, Philippines (AP) — The Philippine health department has declared a polio outbreak in the country nearly two decades after the World Health Organization declared it to be free of the highly contagious and potentially deadly disease.

Health Secretary Francisco Duque III said at a news conference Thursday that authorities have confirmed at least one case of polio in a 3-year-old child in southern Lanao del Sur province and detected the polio virus in sewage in Manila and in waterways in the southern Davao region. Those findings are enough to declare an outbreak of the disease in a previously polio-free country like the Philippines, he said.

The World Health Organization and the United Nations Children's Fund expressed deep concern over polio's reemergence in the country.