Troops have been exposed to it during the gulf war, in Bosnia and in Iraq.

"If DU poses no danger, we need to prove it with statistically valid and independent scientific studies," said Democratic Rep. Jim McDermott of Washington, the amendment's author, who has been sounding an alarm for several years. "If DU harms our soldiers, we all need to know it and act quickly."

Veterans groups and other activists contend that when equipment containing DU is destroyed on the battlefield, exposure to the dust poses radioactive risks to military personnel, as do embedded fragments.

Many refer to it as the next Agent Orange, the chemical defoliant used in Vietnam that was thought at the time to be harmless.

The military has said studies over the past 50 years have proved the health risks of DU to be "minimal."

"While natural and depleted uranium are considered chemically toxic, they are not considered a radiation hazard," according to a Pentagon Web site at 7apr.htm.

The World Health Organization has said no increases in leukemia or other cancers have been linked to exposure to depleted uranium.

In 1997, Congress ordered the military to assess the mental health of all deploying troops. The newspaper, citing Pentagon statistics, said fewer than 1 in 300 service members were referred to a mental health professional before shipping out for Iraq as of October 2005.

Twenty-two U.S. troops committed suicide in Iraq last year, accounting for nearly one in five of all non-combat deaths and was the highest suicide rate since the war started, the newspaper said.

'Chemically active time bombs'

Some service members who committed suicide in 2004 and 2005 were kept on duty despite clear signs of mental distress, sometimes after being prescribed antidepressants with little or no mental health counseling or monitoring. Those findings conflict with regulations adopted last year by the Army that caution against the use of antidepressants for "extended deployments."

"I can't imagine something more irresponsible than putting a soldier suffering from stress on (antidepressants), when you know these drugs can cause people to become suicidal and homicidal," said Vera Sharav, president of the Alliance for Human Research Protection. "You're creating chemically activated time bombs."

Although Defense Department standards for enlistment disqualify recruits who suffer "persistent post-traumatic symptoms," the military also is redeploying service members to Iraq who fit that criteria, the newspaper said.

"I'm concerned that people who are symptomatic are being sent back. That has not happened before in our country," said Dr. Arthur S. Blank, Jr., a Yale-trained psychiatrist who helped to get post-traumatic stress disorder recognized as a diagnosis after the Vietnam War.

'Recruiting has been a challenge'

The Army's top mental health expert, Col. Elspeth Ritchie, acknowledged that some deployment practices, such as sending service members diagnosed with post-traumatic stress syndrome back into combat, have been driven in part by a troop shortage.

"The challenge for us ... is that the Army has a mission to fight. And, as you know, recruiting has been a challenge," she said. "And so we have to weigh the needs of the Army, the needs of the mission, with the soldiers' personal needs."

Ritchie insisted the military works hard to prevent suicides, but is a challenge because every soldier has access to a weapon.

Commanders, not medical professionals, have final say over whether a troubled soldier is retained in the war zone. Ritchie and other military officials said they believe most commanders are alert to mental health problems and are open to referring troubled soldiers for treatment.

"Your average commander doesn't want to deal with a whacked-out soldier. But on the other hand, he doesn't want to send a message to his troops that if you act up, he's willing to send you home," said Maj. Andrew Efaw, a judge advocate general officer in the Army Reserves who handled trial defense for soldiers in northern Iraq last year.

"We just want them to go away," said Bob Papanos of the U.S. Rice Producers Association. "This little company could cause major problems."

Ventria, with 16 employees, practices "biopharming," the most contentious segment of agricultural biotechnology because its adherents essentially operate open-air drug factories by splicing human genes into crops to produce proteins that can be turned into medicines.

Ventria's rice produces two human proteins found in mother's milk, saliva and tears, which help people hydrate and lessen the severity and duration of diarrhea attacks, a top killer of children in developing countries.

But farmers, environmentalists and others fear that such medicinal crops will mix with conventional crops, making them unsafe to eat.

The company says the chance of its genetically engineered rice ending up in the food supply is remote because the company grinds the rice and extracts the protein before shipping. What's more, rice is "self-pollinating," and it's virtually impossible for genetically engineered rice to accidentally cross breed with conventional crops.

"We use a contained system," Ventria Chief Executive Scott Deeter said.

Regardless, U.S. rice farmers in particular fear that important overseas customers in lucrative, biotechnology-averse countries like Japan will shun U.S. crops if biopharming is allowed to proliferate. Exports account for 50 percent of the rice industry's $1.18 billion in annual sales.

Japanese consumers, like those in Western Europe, are still alarmed by past mad cow disease outbreaks mishandled by their governments, making them deeply skeptical of any changes to their food supply, including genetically engineered crops.

Rice interests in California drove Ventria's experimental work out of the state in 2004, after Japanese customers said they wouldn't buy the rice if Ventria were allowed to set up shop.

Anheuser-Busch Inc. and Riceland Foods Inc., the world's largest rice miller, were among the corporate interests that pressured the company to abandon plans to set up a commercial-scale farm in Missouri's rice belt last year.

But Ventria was undeterred. The company, which has its headquarters in Sacramento, finally landed near Greenville, N.C. In March it received U.S. Department of Agriculture clearance to expand its operation there from 70 acres to 335 acres. Ventria is hoping to get regulatory clearance this year to market its diarrhea-fighting protein powder.

There has been little resistance from corporate and farming interest in eastern North Carolina. But the company's work has raised the hackles of environmentalists there.

"The issue is the growing of pharmaceutical products in food crops grown outdoors," said Hope Shand of the environmental nonprofit ETC Group in Carrboro, N.C. "The chance this will contaminate traditionally grown crops is great. This is a very risky business."

Deeter points out that there aren't any commercial rice growers in North Carolina, although the USDA did allow Ventria to grow its controversial crop about a half-mile from a government "rice station," where new strains are tested. The USDA has since moved that station to Beltsville, Md., though an agency spokeswoman said the relocation had nothing to do with Ventria.

The company, meanwhile, has applied to the Food and Drug Administration to approve the protein powder as a "medical food" rather than a drug. That means Ventria wouldn't have to conduct long and costly human tests. Instead, it submitted data from scientific experts attesting to the company's powder is "generally regarded as safe."

Earlier this month, a Peruvian scientist sponsored by Ventria presented data at the Pediatric Academics Societies meeting in San Francisco. It showed children hospitalized in Peru with serious diarrhea attacks recovered quicker - 3.67 days versus 5.21 days - if the dehydration solution they were fed contained the powder.

Ventria's chief executive said he hopes to have an approval this year and envisions a $100 million annual market in the United States. Deeter forecasts a $500 million market overseas, especially in developing countries where diarrhea is a top killer of children under the age of 5. The
World Health Organization reports that nearly 2 million children succumb to diarrhea each year.

But overcoming consumer skepticism and regulatory concerns about feeding babies with products derived from genetic engineering is a tall order. This is especially true in the face of continued opposition to biopharming from the Grocery Manufacturers Association of America, which represents food, beverage and consumer products companies with combined U.S. sales of $460 billion.

Ventria hopes to add its protein powder to existing infant products. There is no requirement to label any food products in the United States as containing genetically engineered ingredients.

The company also has ambitious plans to add its product to infant formula, a $10 billion-a-year market, even though the major food manufacturers have so far shown little interest in using genetically engineered ingredients. But Deeter says Ventria can win over the manufacturers and consumers by showing the company's products are beneficial.

"For children who are weaning, for instance, these two proteins have enormous potential to help their development," Deeter said. "Breast-fed babies are healthier and these two proteins are a big reason why."

Vietnam, which has had almost half of the human cases of A(H5N1) flu in the world, has not seen a single case in humans or a single outbreak in poultry this year. Thailand, the second-hardest-hit nation until Indonesia recently passed it, has not had a human case in nearly a year or one in poultry in six months.

Encouraging signs have also come from China, though they are harder to interpret.

These are the second positive signals that officials have seen recently in their struggle to prevent avian flu from igniting a human pandemic. Confounding expectations, birds making the spring migration north from Africa have not carried the virus into Europe.

Dr. Nabarro and other officials warn that it would be highly premature to declare any sort of victory. The virus has moved rapidly across continents and is still rampaging in Myanmar, Indonesia and other countries nearby. It could still hitchhike back in the illegal trade in chicks, fighting cocks or tropical pets, or in migrating birds.

But this sudden success in the former epicenter of the epidemic is proof that aggressive measures like killing infected chickens, inoculating healthy ones, protecting domestic flocks and educating farmers can work, even in very poor countries.

Dr. Nabarro said he was "cautious in interpreting these shifts in patterns" because too little is known about how the disease spreads.

Other officials agreed.

"To say the disease is 'wiped out' there is probably too strong, too positive," said Dr. Wantanee Kalpravidh, chief of flu surveillance in Southeast Asia for the United Nations Food and Agricultural Organization, which fights animal diseases. The governments of Thailand and Vietnam "believe they got rid of it," she said, "but they also believe that it might be coming back at any time."

Very different tactics led to success in the two countries.

While Vietnam began vaccinating all its 220 million chickens last summer, Thailand did not because it has a large poultry export industry, and other nations would have banned its birds indefinitely. (Vaccines can mask the virus instead of killing it.)

Instead, Thailand culled wide areas around infected flocks, compensated farmers generously and deputized a volunteer in every village to report sick chickens.

It vaccinates fighting cocks, which can be worth thousands of dollars, and even issues them passports with their vaccination records so they can travel, Dr. Nabarro said.

Government inspectors sample birds everywhere; in February, Thailand reported that samples from 57,000 birds had come back negative.

According to Dr. Klaus Stöhr, a flu specialist at the World Health Organization, Thailand and Vietnam also delivered the antiviral drug Tamiflu to even the smallest regional hospitals and told doctors to treat all flu patients even before laboratory diagnoses could be made.

Dr. Nabarro particularly praised the leaders of the two countries for ordering high-level officials - deputy prime ministers - to fight the disease, and for making sure that enough cash to entice farmers to hand over their birds for culling flowed down official channels without being siphoned off.

Hints suggest that the disease is also being beaten back in China, the country where it is assumed to have begun. International officials tend to greet official public health reports from China skeptically, in part because it concealed the outbreak of the SARS virus there for months. It did not officially report any bird cases for years, even though many scientists contend the virus incubated there between its first appearance in humans in Hong Kong in 1997 and the current human outbreak, which began in Vietnam in 2003.

Some top Chinese officials have blamed the reluctance of local officials to report bad news to Beijing. Dr. Nabarro said he recently met a vice premier "who made it clear that they are absolutely determined to get the fullest possible cooperation from provincial authorities."

China's reported human cases have remained low: 8 last year and 10 this year.

Perhaps more important, its poultry cases - which lead to human cases and increase the risk of a mutant pandemic strain - seem to be dropping.

According to the World Health Organization, China said it had outbreaks in 16 provinces in 2004. In 2005, it reported outbreaks in only 12 provinces, but one in November was so large that 2.5 million birds were culled to contain it.

After that, the Agriculture Ministry announced that it would vaccinate every domestic bird in China, which raises and consumes 14 billion chickens, ducks and geese each year. The official news agency reported about the same time that a fake flu vaccine, possibly with live virus in it, might have spread the disease.

Dr. Stöhr, who is in charge of W.H.O. flu vaccine efforts, said he was told by Chinese agriculture officials that the country was now producing 46 billion doses of poultry vaccine a year, and was supplying vaccines to Vietnam.

China's most recent monthly reports describe much smaller outbreaks than were previously common: findings of a few dead wild birds and culls of 126,000 birds in one spot and 16,000 in another, for example.

"We are hopeful that China has turned the corner," Dr. Nabarro said.

In Cambodia and Laos, which separate Thailand and Vietnam, the situation is vague.

Laos has reported no human cases and last reported poultry outbreaks two years ago. Cambodia's reported human cases dropped to two this year, from four last year. No poultry outbreaks were reported, but surveillance is so spotty that some must have occurred and gone unnoticed, Dr. Kalpravidh said, because the country's six human victims were infected by poultry.

Cambodia was slow to compensate farmers for their birds because of problems with corruption in a previous cash-for-guns program.

Health specialists generally agree that there is little clear chance of infected birds landing in the United States.

Where the Southeast Asian governments have taken action, however, the risk of the virus returning is ever present, Dr. Nabarro said.

For example, he said, it probably exists in Vietnam in Muscovy ducks, which can harbor the virus but do not get sick, and it has turned up in isolated birds in open-air markets near the Chinese border. (Single birds do not constitute an outbreak.) Since Chinese farmers can get three times as much for a chicken in Vietnam as they can at home, the temptation to smuggle persists.

"Tomorrow, the whole thing could change again," Dr. Nabarro said. "We need to be on the alert at all times."

"All meat, internal organs and parts from this cattle will be incinerated, and there is no danger that they will be circulated in the market," the ministry statement said.

The confirmation comes as Japanese and U.S. officials prepare to meet as early as next week to discuss lifting Tokyo's ban on American beef.

Japan initially banned U.S. beef in December 2003, following the first discovery of mad cow disease in the United States.

That ban was eased last December to allow the importation of meat from cows aged 20 months or less - seen as posing a lower risk of having the disease - but the ban was later tightened following the faulty beef shipment in January.

Mad cow disease, or bovine spongiform encephalopathy, is a degenerative nerve disease in cattle. Eating contaminated meat products has been linked to the rare but fatal human variant Creutzfeldt-Jakob disease.

The couple are the first to take advantage of a relaxation in the rules governing embryo screening.

When the technique was developed in 1989 it was allowed only for genes that always cause disease, such as those for cystic fibrosis. However, it was approved last year for the eye cancer, which affects only 90 per cent of those who inherit a mutated gene.

The pregnancy will increase controversy over the procedure, which the Government's fertility watchdog authorised on Wednesday for genes that confer an 80 per cent lifetime risk of breast and bowel cancer.

Critics argue that the action is unethical because it involves the destruction of some embryos that would never contract these illnesses if they were allowed to develop into children. Even those that would potentially become ill could expect many years of healthy life first, and some of the disorders involved are treatable or preventable.

The mother-to-be, who wishes to remain anonymous, conceived after receiving treatment from Paul Serhal, of University College Hospital, London.

Mr Serhal has pioneered the use of pre-implantation genetic diagnosis (PGD) to detect heritable cancers in Britain, though it has been used successfully before in the United States. The Human Fertilisation and Embryology Authority's (HFEA) decision to award him licences to screen for retinoblastoma and a form of bowel cancer were reported exclusively in The Times. Mr Serhal is treating several couples with the disorder.

"We are all elated," he said yesterday. "We are talking about annihilating this abnormal gene from the whole family line. We do this often, but it is always extraordinary when it comes off."

Mr Serhal's clinic is planning to apply to screen a patient's embryos for the BRCA1 gene that raises the lifetime risk of breast cancer to 80 per cent.

Though the HFEA has now agreed in principle that such screening will be allowed, clinics must still obtain a separate licence for every patient.

Retinoblastoma accounts for 11 per cent of all cancers that develop in the first year of life. In almost half of cases, it is caused by an inherited mutation in a gene called RB1. Parents with this defective gene have a 50 per cent chance of passing it on to a child, and it causes tumours in 90 per cent of those who inherit it. The mutation also raises the lifetime risk of suffering other cancers from a third to more than half.

Libby Halford, chief executive of the Childhood Eye Cancer Trust, a retinoblastoma charity, welcomed the news. "This gives families a choice," she said. "We know now that there is an effective test."

Josephine Quintavalle, of the embryo rights group Comment on Reproductive Ethics, said: "We mustn't forget the embryos that were not given a chance to live. This is a worrying application because we are looking at a condition that is treatable."

"It's important that we inform people about this because patients who have taken the drug will need increased surveillance by their physicians and increased awareness of their risks in the year subsequent to stopping the drug. And that risk may extend beyond a year; we simply don't know," Nissen told Reuters in a telephone interview.

Merck said on Thursday that patients who took Vioxx in the study had no greater risk of heart attacks or strokes a year after stopping the medication than those who got placebos.

While there were 28 heart attacks or strokes in the Vioxx group compared with 16 in the placebo group, Merck said those numbers failed to reach statistical significance.

"In the one year after Vioxx was stopped there was a 75 percent greater risk of having an adverse event," Nissen said.

"What this means is that, surprisingly, in the year following discontinuation of Vioxx the relative risk remains approximately as high as it was when people were actually taking the drug. That is very clear from the data," Nissen said.

Merck withdrew Vioxx from the market in September of 2004 after a three-year study showed it doubled the risk of heart attack and strokes in patients taking it for at least 18 months.

Nissen said because there was a relatively small total number of adverse heart events in the follow-up year, Merck was able to claim no statistically significant difference even though the actual numbers tell a different story.

"What is important is that the hazard stays constant even after you stop the drug," Nissen said.

In response to Nissen's comments, Merck said it stands by what it said in Thursday's statement and subsequent conference call.

"We were as transparent as possible in this whole process," Merck spokesman Michael Heinley said. "We were trying to get out as much as we could recognizing there were a lot of people interested in this data."

Merck is facing more than 11,500 lawsuits from people who claim to have been harmed by Vioxx, or their survivors.

The company's general counsel said on Thursday that the one-year follow-up data should shield it from lawsuits that might be filed by people who suffered heart attacks or strokes after they were no longer taking Vioxx.

But Nissen said: "What counts is the relative risk as you go forward, and the bottom line is there is a constant risk even after the drug is stopped.

"That is the only clear message from the study. The rest is spin," he said.