A new mosquito net, manufactured in Tanzania and now being tested there, is expected to go far in helping the continent fight malaria.

As the last rays of sunlight fade into the horizon, Neema Gunda checks the mosquito curtain hanging from her front door and the nets enclosing the beds where she and her five children sleep.

In her village of Manyatta, overlooking the foothills of Mount Kilimanjaro in Tanzania, sunset signals the arrival of hordes of mosquitoes, which, besides being annoying, can be deadly.

Many mosquitos carry the parasite that causes malaria, which accounts for about 20 percent of all deaths among children under age five in Africa.

In the past, Ms. Gunda took her children to the hospital as often as twice a month at the height of mosquito season to receive treatment for their high fevers, headaches, vomiting, muscle aches, and other symptoms of the disease.

But ever since Ms. Gunda starting using her long-lasting insecticidal nets five months ago, malaria has disappeared from their lives.

Ms. Gunda says when she first received the insecticidal nets, she would put newspapers underneath the curtain covering the front door before closing the door. In the morning, she says, the newspapers would be full of dead mosquitoes. She urges her neighbors to get similar nets for their houses.

Ms. Gunda's family and more than one hundred others in Manyatta are participating in a pilot project to test the effectiveness of a long-lasting insecticide-treated mosquito net, whose trademark is Olyset.

Conventional insecticide-treated nets, which were developed in the mid 1980s, must be soaked every four to six months in an insecticide to be effective, whereas Olyset incorporates an insecticide within its fibers.

A spokeswoman for the Roll Back Malaria Partnership Secretariat, Pru Smith, explains the problems involved with re-treating regular nets.

"You might not re-treat it because, A., you've got to buy insecticide, and B., you've got to go through [the effort of] taking it down, washing it, putting insecticide on  [and] you should protect yourself when you're doing that. You need gloves, you should wear some sort of face protection. To do all that, you're asking quite a lot of people," says Mr. Smith.

The Roll Back Malaria Partnership is an initiative started by U.N. agencies and the World Bank that brings together all sectors to fight malaria worldwide.

Chemically treated nets, both long-lasting and conventional, are more effective in the fight against malaria than plain nets because the chemicals maim or kill off mosquitos rather than merely prevent them from biting people. According to the World Health Organization, people are up to 60 percent less likely to contract malaria if they use insecticide-treated nets.

Within the last few years, the World Health Organization approved two long-lasting insecticidal nets that do not need to be soaked in chemicals. 

Olyset, one of those nets, is built with fibers containing permethrin, which is slowly released over a five-year period.

The only factory in Africa to manufacture the Olyset net, or any long-lasting net, is A to Z Textiles in Arusha, about 20 kilometers from Manyatta Village. It has produced about 300,000 nets over the past year.

The chief executive officer of A to Z Textile Mills, Anuj Shah, says he is enthusiastic about the teamwork that has gone into the production of Olyset nets in Africa.

"One of the most interesting and exciting aspects of this project is the transfer of technology back to some of our partners," he said.  "These African innovations and cross-fertilization of ideas are certainly a good omen for the future."

Partners in the Olyset venture include Sumitomo Chemical Company in Japan, which is providing the manufacturing technology, ExxonMobil in the United States, which is supplying chemicals and advice, a non-profit global venture fund in the United States called Acumen Fund, which put up the financing, and several United Nations agencies, which monitor quality control and have purchased nets.

Mr. Shah said that preliminary results of the Manyatta trial are encouraging.

One downside of the Olyset and other long-lasting nets is that they are relatively expensive. The Olyset net retails for about $5.50, which puts it beyond the reach of many poor families.

Conventional insecticide-treated nets cost between $2.50-$3.50. But experts say, in the long run, conventional nets may be just as costly, or more so because, at least twice a year, people need to purchase insecticides in which to soak the nets.

The executive director of the independent foundation the Global Fund to Fight AIDS, Tuberculosis and Malaria, Richard Feachem, acknowledges that few Africans have access to conventional insecticide-treated mosquito nets, let alone long-lasting nets.

"Certainly, in most of Africa, if you hunt hard enough, you can find a net, but it probably isn't a treated net, it's probably just a regular net," he said.  "And so access to treated nets in Africa in most countries remains quite low.  We need to expand that."

Doictor Feachem said The Global Fund has approved the purchase of one million insecticide-treated nets in its existing programs in Africa.

He urges countries receiving Global Fund assistance to purchase the nets for low-income people as an effective way of fighting malaria.

Back in 2000, a summit on malaria held in Abjua, Nigeria called for the purchase of enough nets to allow pregnant women in Africa and 60 percent of children under five to sleep under insecticide-treated nets. This target will require 32 million nets, but experts say many more nets will be needed.

According to the Africa Malaria Report 2003, 18 African countries have reduced or eliminated taxes on nets to make them more affordable.

Groups such as the U.N. children's agency are urging governments and donors to provide free insecticide-treated nets to low-income households or to offer these nets at highly subsidized rates.