A 10 month-old baby is the first recorded case of polio in the Gaza city of Deir al-Balah, the Palestinian health ministry said Friday.

The child, who had symptoms of the highly infectious disease, had not received any doses of the polio vaccine.

Tests conducted in Amman, the capital of Jordan, confirmed the infection in the baby. Last month, tests found the poliovirus in wastewater samples in Gaza.

In a major worry, the World Health Organization (WHO) said three children in Gaza have already been found with “acute flaccid paralysis” — the onset of weakness or paralysis with reduced muscle tone that is a common symptom of polio. “Their stool samples have been sent for testing to the Jordan National Polio Laboratory,” the Geneva-based U.N. agency said.

The Palestinian ministry said in a statement that it will implement a vaccination campaign in the coming few days targeting children under the age of 10.

The World Health Organization and UNICEF called for seven-day pauses in the war in Gaza starting at the end of August to vaccinate 640,000 Palestinian children against polio following the discovery of the virus in wastewater in two major cities last month.

The WHO said Friday that the vaccination campaign will have two rounds, with the second in September. In each, children under the age of 10 will be given two drops of the oral vaccine against type 2 of the polio virus, it said in a statement.

WHO said a variant of type 2 was discovered in mid-July in wastewater samples from southern Khan Younis and central Deir al-Balah, and linked to a variant of the polio virus last detected in Egypt in 2023.