The 200,000 American soldiers stationed in Saudi Arabia have been issued an array of sophisticated tools to fight a desert war, ranging from special glasses to protect against lasers to suits and masks that would counteract the effects of possible chemical weapon attacks.

But to cope with the dust storms that rake the desert, American GIs use the same simple remedy that generations of nomads and cowboys have relied on: They tie scarves across their faces.

Two months after Operation Desert Shield began, many GIs are finding that the major challenges have less to do with war than with living standards. Most days, their concerns involve water, food, sanitation and shelter. Among the enemies are disease-carrying insects and searing dry heat. The chief risks -- in the absence of fighting -- are dehydration, diarrhea and other gastrointestinal ailments.

Medical historians know that in previous wars, soldiers were more likely to die of disease and accidents than in combat. It was in World War II that battle deaths for the first time exceeded those from other causes -- in large part because of better medical care including antibiotics that effectively treated bacterial infections.

Yet illness and accidents remain a major problem for military doctors. Among surviving troops during wartime, soldiers are still more likely to end up in the hospital for non-combat-related problems. In Vietnam, as many as 73 percent of hospital admissions were caused by disease, according to Maj. Gen. Sturgeon Neel in his study of medical support services for the U.S. Army in Vietnam.

All this makes the prevention of disease and accidents "as critical as arming soldiers for the prevention of combat wounds," said Col. Frederick Erdtmann, preventive medicine consultant to the Army surgeon general.

So far in the Persian Gulf, there have been very few casualties, Army officials report. Accidents have claimed 19 lives, including 12 killed in the crash of a cargo plane bound for Saudi Arabia and one who was accidentally electrocuted aboard the USS Antietam. No deaths have been reported from heatstroke or disease.

"Our primary concern -- dehydration -- is being well controlled," said Maj. Patrick Kelley, chief of the Department of Advanced Preventive Medicine Studies at the Walter Reed Army Institute of Research.

"Soldiers are making jokes about how much water they are drinking," said Erdtmann. "But that's good. That means they are paying attention."

Keeping soldiers healthy is essential for combat readiness -- especially in the desert, where dehydration and diarrheal diseases have been known to immobilize troops. During the North Africa campaign in World War II, 30 percent of the German forces under Field Marshal Erwin Rommel were felled by diarrhea. Military historians point to the lack of sanitation as a factor in his defeat by British troops.

These days, desert training exercises are structured to help prevent casualties from heatstroke, dehydration and diarrheal illness. Military doctors estimate that up to seven soldiers per 1,000 suffer heat-related problems -- a figure that would mean that close to 1,000 cases might be expected for soldiers participating in Desert Shield. "Yet you can count on your fingers the number of cases of heatstroke we've had," Erdtmann said. Military officials say that fewer than a dozen soldiers have suffered heatstroke.

Diarrheal illness, the second major health threat after dehydration, can last anywhere from 24 hours to several weeks. It has several causes: stress, too much salt in drinking water, food tainted with bacteria or viruses and the omnipresent swarms of large flies known in Saudi Arabia as filth flies.

Filth flies don't bite, but they do flit around garbage dumps and transmit diseases caused by such bacteria as salmonella and shigella. These agents can lead to dysentery -- a bowel inflammation that causes pain, cramps and severe diarrhea -- and can be fatal.

Other gastrointestinal illnesses are caused by E. coli -- the strain of bacteria responsible for much of travelers' diarrhea worldwide. E. coli and other troublesome organisms can be transmitted through water -- the reason troops are issued iodine tablets and drinking water is chlorinated. But they are also food-borne, a problem that the Army combats in Saudi Arabia by having military food inspectors frequently check not only military supplies but also local food sources; military veterinarians routinely examine livestock and slaughterhouses to guarantee that meat is disease-free and is being stored at proper temperatures.

Sanitation is another concern. In the desert, where water is rare, commodes don't flush in the conventional sense. Bodily wastes go down a narrow pipe that leads into a hole. A small amount of water is used not to "flush" the toilet but to cleanse the body. Toilet paper is not usually used. So when U.S. soldiers tried to use local facilities, "they were constantly stopping up these toilets," Erdtmann said.

Insecticides help control much of the problem with filth flies and other insects. Soldiers are also taught to avoid freshwater pools that often contain parasites that burrow into the skin and cause the infection schistosomiasis.

Rolling shirt sleeves and pant legs down at night can help avoid bites from sand flies -- pinhead-size insects that suck blood from capillaries and can cause a flu-like viral infection and fever that lasts several days. Sand flies also spread a far more serious illness called leishmaniasis, which can produce skin ulcers and cause organ damage.

To minimize the chance of insect-borne illnesses, troops slather on a new long-lasting insect repellent lotion and wear uniforms impregnated with the insecticide permethrin.

Soldiers also take bitter-tasting chloroquine tablets to prevent malaria, and all have been vaccinated against typhoid and cholera. Injections of immunoserum globulin protect them for three-month intervals against hepatitis A, a viral infection that is usually contracted by eating contaminated food or drinking tainted water.

Protective glasses -- ballistic laser eye protection systems -- shield troops' eyes from the damage caused by inadvertently looking into the sights of laser range finders on weapons. They protect against the ultraviolet rays from the intense Saudi sun and are strong enough to deflect flying debris such as shrapnel. Also in each soldier's personal medical kit are three auto-injectors of atropine to be used as antidotes in the event of exposure to chemical weapons.

Suits and masks issued to every American soldier for protection against nerve gas protect them from biological agents, as well. Last month, U.S. intelligence officials reported that Iraq has produced a stockpile of biological weapons that includes respiratory anthrax, a bacterial infection that causes hemorrhaging in humans and cattle and can be fatal if not treated.

In the U.S., the Michigan health department produces a vaccine used to immunize researchers who handle the bacteria in laboratories. The vaccine, which involves a series of injections, could also be used to vaccinate soldiers, said David Huxsoll, a former director of the Army's Medical Research and Development command at Ft. Detrick, Md.

Minimizing or preventing psychological stress is another concern. One stress-reducing strategy is to rotate troops in units rather than transferring individual soldiers. In Vietnam, individual soldiers were rotated, creating sharp divisions between short-timers -- those who had just weeks left to serve -- and soldiers who faced a much longer tour of duty. "We've learned {that keeping units together} helps sustain people," Fagan said.

At the same time, the military is focusing on how to help families left at home, especially those headed by single parents. The Army has set up a special family support program to assist families with problems ranging from child care to finances while the soldiers are away.