Could killer Ebola virus be used as a bioweapon?

A U.S. federal air marshal was stabbed with a syringe at the airport in Lagos, Nigeria, on Sunday, an incident that is raising concerns about whether the deadly Ebola virus could be harvested from the widespread outbreak in West Africa and used as a bioweapon.

Initial tests on the substance in the syringe, conducted at a special biodefense forensics laboratory at Fort Detrick, Md., did not detect the virus or any other threatening agent, an FBI spokesman, Christos Sinos, said Wednesday. The mar- shal, who arrived in Houston on Monday, was examined there and has been released from the hospital with no sign of illness, according to a Transportation Security Administration spokesman.

Experts say it would be extremely hard for a group to grow large amounts of the virus and turn it into a weapon that could be dispersed over a wide area, infecting and killing many people.

“The bad guys are more likely to kill themselves trying to develop it,” said Dr. Philip Russell, a retired major general who was the commander of the Army Medical Research and Development Command.

But it is harder to totally discount the possibility of a smaller attack, perhaps like the one at the airport in Lagos. Another possibility would be suicide infectors, people who deliberately infected themselves and carried the virus out of the epidemic zone to sicken others.

“To truly isolate the virus takes a lot of resources,” said Dr. Ryan C.W. Hall, a Florida psychiatrist who has written about the psychiatric impacts of bioterrorism attacks. “But if you have people who are willing to die and will- ing to inject themselves with the blood of someone who has been infected, you don’t need a Biosafety Level 4 lab,” he said, referring to the special containment facilities used to work with the most deadly pathogens.

Such an attack would not kill many, or even any, people in an advanced country like the United States. But it could strike terror and cause economic disruption. “Someone gets sick on an airplane, conceivably everyone on that airplane has to be quarantined,” said Dr. Robert Kadlec, who was special assistant on biodefense policy to President George W. Bush.