GENEVA/SANAA: Yemen’s cholera outbreak has infected 612,703 people and killed 2,048 since it began in April, and some districts are still reporting sharp rises in new cases, data from the World Health Organization and Yemen’s Health Ministry showed Tuesday. The overall spread of the epidemic has slowed in the past two months, with the daily number of new suspected cases cut to around 3,000 in recent days.

However the epidemic, the most explosive on record in terms of its rapid spread, has continually confounded expectations. Soon after it began, WHO saw a worst-case scenario of 300,000 cases within six months. But by the end of June, WHO was hoping 218,000 cases might be the halfway mark. In late July it said the spread had peaked after infecting 400,000.

Epidemics normally decline as quickly as they arise, so the peak of the disease – that is spread by contaminated food and water – should be roughly half the total caseload.

But the decline in the epidemic has been bumpy, and the number of new cases rose in two of the past four weeks. WHO spokesman Tarik Jasarevic said some of the most affected areas, such as Sanaa City and the governorates of Al-Hajjah and Amran, had seen falls in the numbers of new cases.

But there had been a “sudden and significant increase” in the number of suspected cases reported from 12 districts, in the governorates of Hudaida, Jawf, Al-Mahwit, Ibb, Dhamar, Bayda and Aden. “WHO is currently investigating the reason for this increase,” Jasarevic said.

An Arab-led coalition intervened in the civil war in March 2015 to restore to power Yemen’s ousted internationally recognized government and has launched thousands of airstrikes against the armed Houthi movement, which controls Sanaa and much of the country’s north. The security vacuum in Yemen has also emboldened Al-Qaeda’s local branch in parts of the country.

In a report published Tuesday, the United Nations said the Islamist militant group has become “operational” in the southwestern city of Taiz.

The city has faced “unrelenting” shelling in 2 1/2 years of escalated fighting in the impoverished country.

In other developments, Yemen’s former President Ali Abdullah Saleh appeared on TV late Monday to deny there are any divisions between him and his allies the Houthi rebels.

But tensions have risen in recent weeks between the two factions, and Saleh’s strange appearance, in an interview that was abruptly cut off, was unlikely to dispel rumors he is under some form of house arrest. “There is no crisis and conflict at the moment,” the 75-year-old strongman said in an interview on Al-Yemen Al-Yom television, which his party controls.

On Aug. 24, hundreds of thousands put on a show of force for Saleh at a rally marking the 35th anniversary of his Arab nationalist General People’s Congress party. “There were fears and suspicions that the rally would be a coup” against the Houthis, the former president said. In response, Saleh said he had sent two letters to Abdel-Malek al-Houthi, head of the rebel group, to reassure him. “He reacted positively,” he added.