In the face of a global economic downturn, can researchers, funders and governments maintain a pricey, long-lasting war against malaria — a wily, world-class killer?

It's one of many tough questions malaria experts from around the world will tackle during a three-day, invitation-only Malaria Forum hosted this week by the Bill & Melinda Gates Foundation, a major player in the drive to eradicate malaria.

The event, headlined "Optimism and Urgency," begins Monday with a lineup of top global health leaders from around the world. They include the director-general of the World Health Organization (WHO), leaders of public and private malaria programs in countries from Kenya to Zanzibar, and key drug-industry officials.

Optimism? Yes, because the first malaria vaccine is now in final trials in Africa. Optimism, too, because insecticides and bed nets appear to have cut deaths by more than 200,000 a year.

Urgency, though, because an estimated 780,000 people — most of them children in Africa — still die every year from malaria. The trial vaccine is only half-effective. And the female Anopheles mosquito and her parasites are developing resistance to insecticides and drugs.

"Malaria is an extremely complex disease that has been causing deaths and social disruption since the beginning of recorded human history," Dr. Margaret Chan, WHO's director-general, said last year. "This is a disease that can take full advantage of any lapse in investment, vigilance or control."

In 2007, at its first Malaria Forum in Seattle, the Gateses issued a call for eradication of malaria, then killing about a million people a year. The bold challenge stunned many experts, who knew well the long list of failures to staunch the death toll from the disease in Africa and parts of Asia and South America.

Some believed eradication was a crazy, expensive and likely unattainable goal, arguing the money could be better spent on controlling the disease and treating those infected.

Plasmodium falciparum, the deadliest malaria-causing parasite, has been outwitting many of the best and brightest since 1955, when WHO launched a campaign to eliminate the disease. By the 1970s, the parasite's mosquito host had won, and the campaign became, as one report called it, "the forever war."

The Gates Foundation, seeing itself as a catalyst, bringing attention and funds to the fight, has invested $1.5 billion and committed $260 million more. And it's not enough to do the job.

"It's a real grand challenge," says Stefan Kappe, a malaria-vaccine researcher at Seattle BioMed, one of four labs in the world where test subjects volunteer to be bitten by malarial mosquitoes.

"It's probably more difficult than sending someone to the moon."

Success stories

To be sure, there will be success stories told over the next three days.

The Roll Back Malaria Partnership, a worldwide consortium, says malaria deaths dropped by 38 percent in the past decade — just using bed nets, diagnostics, treatment drugs and insecticides.

"In less than a decade, it's safe to say, it's truly astounding the progress that has been made in the world of malaria control," says Dr. Kent Campbell, director of the Malaria Control Program at PATH, the Seattle global-health nonprofit. "Malaria actually produces on investment."

A vaccine called RTS,S is now in the final stages of testing in more than 15,000 children in Africa. The vaccine, 50 percent effective in earlier tests, was developed by British drugmaker GlaxoSmithKline with the Gates-funded Malaria Vaccine Initiative at PATH.

Ashley Birkett, head of MVI research and development, says the breakthrough is key: "If we can get to 50 percent, why can't we get to 80 or 90?"

Researchers are now approaching vaccines from every angle, including a so-called "transmission-blocking" vaccine that wouldn't stop people from getting sick, but would stop mosquitoes from infecting others. It seems that against malaria, every weapon is needed, including a vaccine that depends on altruism to work.

"Parasites are tough," says Birkett. "We're in new territory here."

Cause for concern

Along with the successes, the forum will focus on malaria eradication's many challenges.

Those who believe malaria eradication is unrealistic have history on their side: So far, nothing has overcome the habits of mosquitoes, their parasites and even humans, prone to poking an arm out of a bed net on a muggy night.

Some experts are focused on new troubles, ranging from drug and insecticide resistance to global economic woes — topics to be explored at the forum."There is excitement about RTS,S," says Dr. David Brandling-Bennett, deputy director of the malaria program at the Gates Foundation. "There's also excitement about what's been accomplished — and recognition that we're not there yet."

Getting there, of course, will take money. Conservatively, about $4.7 billion will be needed just for research and development until 2015, according to a recent report.

But since 2007, when Bill and Melinda Gates first called for malaria eradication, the financial meltdown has tightened budgets. As Chan once noted, the true killers in public health are the lack of resources and political commitment.

"Quite frankly, I think we're all concerned about whether the public financing from major donor countries and even from the endemic countries — which have to put their own resources in — can continue at the level that's needed," says Brandling-Bennett. "We need the developed world, the industrialized world, to continue its commitments."

Benefits of helping

From WHO to the U.S. Agency for International Development, officials are well aware U.S. taxpayers are cranky and feeling overburdened. Why spend tons of money on a disease we don't even have?

Dr. Robert Newman, director of WHO's global malaria program, says it's a moral choice.

No child should die for lack of a $5 bed net, a 50-cent diagnostic kit or a 35-cent treatment, he says. "I think we can live more equitably."

Both he and Dr. Raj Shah, administrator of USAID, argue that reducing malaria in faraway countries is in U.S. taxpayers' interests.

Countries devastated by disease, they say, aren't likely to become stable, strong trading partners — think South Korea, says Shah. More likely, like Afghanistan, they will be vulnerable to unstable political conditions.

"Ultimately, having more South Koreas and fewer Afghanistans is in our country's strong national interest," Shah says.

Still determined

To Kappe at Seattle BioMed, the developments cement his conviction that malaria elimination — not control — must be the goal.

All the bed nets and spray in the world won't finish off malaria, nor will a half-effective vaccine, he says. "That's not good enough."

Thanks to funding by the Gates Foundation and others, Kappe is in the early stages of testing a vaccine made from genetically altered parasites.

At his Seattle BioMed lab, mosquitoes sip infected blood through artificial skin; later, a tech will dissect their salivary glands, extracting microscopic parasites.

The mosquito is the "most dangerous animal in the world," he says. "We want to understand our enemy."

Carol M. Ostrom: 206-464-2249 or costrom@seattletimes.com