MANILA — The Philippines on Thursday announced an outbreak of polio, 19 years after the World Health Organization declared the Southeast Asian country free of the infectious disease.

Health Secretary Francisco Duque said government scientists have confirmed the “re-emergence of polio” after one case in the southern province of Lanao del Sur and another suspected case of the disease. He blamed “poor immunization coverage,” a lack of sanitation and proper hygiene and poor surveillance by health workers as among the reasons the disease returned.

Polio is an infectious disease that can spread rapidly and mainly affects young children. It can cause muscle weakness, paralysis and, on rare occasions, it can be fatal. There is no cure for polio, but it can be prevented with multiple doses of polio vaccines.

Despite aggressive eradication efforts around the world, the disease has hung on in a handful of countries and even gained a stronger foothold in some, like Pakistan and Afghanistan. There are currently cases this year in several African countries, such as the Central African Republic and Somalia.