Rose Chikonde didn’t expect her home to be sprayed for mosquitoes today — but she’s delighted when the workers show up at her door.

The Zambian woman quickly gathers up her food and dishes and moves them to the front yard. Wearing respirators and overalls, the workers apply a light coat of DDT to the interior walls.

Neighbors stream from their houses in the dense slum on the fringe of Lusaka, the capital city. More than 150,000 people live in this area, called Kanyama. Most earn less than a dollar a day. All are eager to have their homes sprayed.

“Malaria is so bad here,” says one man, who is disappointed to learn his house isn’t on the list today.

Many of the dwellings are little more than hand-built walls topped with a sheet of corrugated tin. Rocks anchor the roofs in place. Puddles the size of swimming pools make navigating the dirt roads by car a white-knuckle experience.

Despite the difficulties, more than 70percent of homes have been sprayed with DDT, which was recently approved for use again by the World Health Organization. Gates Foundation money equipped workers with handheld computers and GPS systems, to track progress in neighborhoods with no addresses or street names.

Chikonde, who offers four boiled eggs and two small bottles of cooking oil for sale on a table in her yard, says she has no mosquito nets. Last year, she spent two weeks in the hospital with malaria. Her husband is sick now, though he went to work.

“People are happy because this medicine is free,” she says. “We hope it will help.”

Sandi Doughton