Nerve Gas Might Have Long-Term Effects

WASHINGTON —  Low levels of sarin nerve gas affected behavior and organ functions in laboratory animals at least a month after exposure, suggests new research that may provide clues to the mysterious illnesses of Persian Gulf War veterans.

In separate Army-sponsored studies, scientists observed behavioral problems, brain changes and immune system suppression in the animals many days after exposure to doses that caused no immediate effects, such as convulsions or pupil constriction.

Both studies involved rodents, and “that’s a big leap to human beings,” said Melinda Roberson, a behavioral neuroscientist involved in a study still underway.

Even so, the studies provide new data in an area where a lack of research has made it impossible to conclude whether the illnesses of Gulf War veterans are linked to low-level sarin gas exposure.

“They are pushing back the frontiers of biological effects of low levels of sarin. The evidence is building,” said Dr. Francis O’Donnell, a medical consultant for the Defense Department who helps track research into Gulf War illnesses.

Veterans of the 1991 war have suffered from various illnesses they believe are linked to their service in the gulf. Symptoms include chronic fatigue, diarrhea, migraines, dizziness, memory problems, loss of muscle control and loss of balance.

Most scientists have blamed stress. Some veterans attribute the health problems to toxic substances they encountered in the gulf, including sarin, a toxic chemical weapon that is lethal at high levels. Others suggest it may be a combination of the factors.

The Pentagon has identified about 130,000 troops it believes were exposed to low levels of sarin in 1991 when U.S. forces destroyed a weapons depot at Khamisiyah in southern Iraq. Some veterans believe other sarin exposures occurred.

On its Web site, the Pentagon tells veterans that “current medical evidence indicates that long-term health problems are not likely.”