Islamabad, Pakistan (CNN) -- Amid the overwhelming flood disaster in Pakistan, the world has "no choice but to be optimistic and to have hope" that things can improve there, actress and humanitarian Angelina Jolie told CNN Wednesday.

Jolie is in the country as the personal envoy of United Nations High Commissioner for Refugees Antonio Guterres. She spoke to CNN from Islamabad after touring flood-hit areas of Pakistan, including the northwest Khyber Pakhtunkhwa region.

She described meeting a couple in their 70s who live on a pension and who watched as floodwater destroyed the family home they had worked hard to build.

"The woman is so embarrassed with her situation, and the man spoke of the fact that he never felt in his lifetime he is ever going to be able to recuperate what he's lost -- that he would never again have nice things, he would never have a nice bed, a nice house," Jolie told CNN.

"They lived in this place since 1972 and raised their children and their grandchildren there. And in a moment, a few hours, it was completely gone."

She said the area the couple lived in is now covered in mud and dirt, with feces in the fly-covered river nearby, all because of the floods.

"It doesn't have the dignity that they deserve to live in -- anybody deserves to live in," Jolie said.

The couple lives in the village of Mohib Banda, where some 70 percent of the homes were destroyed or badly damaged by the swirling floodwater, according to the UNHCR.

The death toll in the country has climbed to 1,738, the Pakistan Disaster Authority said over the weekend.

Almost 21 million people have been affected by the flooding, Valerie Amos, the new U.N. emergency relief coordinator, said Monday.

Water-borne illnesses from contaminated floodwaters have erupted nationwide. At least 1 million Pakistanis have crippling diarrhea or respiratory infections, and about 65,000 cases of malaria have been reported.

Jolie's visit is intended to highlight the suffering of the millions of flood victims and the need for continuing aid for the displaced.

One reason relatively few people have paid attention to the suffering in Pakistan, Jolie said, may be disaster fatigue. She pointed out Pakistan has endured several disasters in recent years, including an earthquake in 2005 that killed more than 70,000 people.

"We tend to focus on one issue at a time, because that seems to be what people can absorb and care for," she said.

She added that it's difficult to convey the story of the disaster in Pakistan, and that even she had no idea what she would face.

"When I was standing in one of the houses, it was nine feet tall, the water. It was not a flood that made everything wet for a (while). It washed away children right out of their parents' hands. It destroyed lives."

Jolie said she would want people to remember this: "They are people. They are family, and lovely, lovely, hard-working people and beautiful children, and they deserve dignity and assistance, and we have to treat them with respect and try to preserve what we can of their livelihood and their future."

The Pakistani people are resilient and will move on, Jolie said, but she urged international support to help them do that.

"I think we have no choice but to be optimistic and to have hope," she said. "I think without that, we are just lost, and things deteriorate."