The GW Hospital has tested about 500 people for anthrax exposure during the past two weeks, as spores of the bacteria are found in more buildings in the D.C. area.

Four people who were in high-risk areas were admitted for further evaluation after they showed symptoms of anthrax, said hospital spokeswoman Marti Harris. Hospital officials declined to comment on whether the patients are students.

Harris said others are receiving treatment for possible exposure but there are no confirmed cases of anthrax.

High-risk areas include the Capitol, congressional office buildings, mail facilities for the Supreme Court, White House and State Department and other places where the spores have been found.

Harris said more than 100 people came for testing on Friday – at the end of a week of more anthrax discoveries and two resulting deaths in the area – and medical personnel are “extremely busy.”

Sophomore Ben Schmidt works as an intern near the exposure area in the Senate Hart office building and was tested at the hospital two days after anthrax was detected Oct. 15. He said doctors gave him a nasal swab test and told him they would inform him if he tested positive.

“They gave me a three-day supply of doxycycline and never called me,” he said. “But on Oct. 21 some doctor called me and said, ‘even though you tested negative, that doesn’t mean you are free of anthrax bacteria or spores.'”

When the doctor called back, Schmidt received a 60-day supply of doxycycline to prevent infection in case he is exposed.

Emergency room physician Dr. Ray Lucas said doctors are looking at patients’ symptoms, although the main indicator to whether someone will be treated is if they were in a high-risk area.

“If people don’t have symptoms, it doesn’t mean they will not get treated,” Lucas said.

Since the discovery of anthrax in Sen. Tom Daschle’s (D-S.D.) office, 471 people have been tested, as of Friday 4 p.m., according the hospital Web site.

There are six-day and 60-day doses of antibiotics that treat anthrax. The smaller dosage is provided after any suspected exposure, even for people who do not require treatment. The 60-day treatment is given to people who have been exposed or have a high likelihood of exposure, according to Center for Disease Control guidelines.

Lucas said doxycycline is cheaper and just as effective as Cipro in treating anthrax.

“The strains of anthrax that have been detected are sensitive to several antibiotics, including doxycycline and cipro,” Lucas said.

According to new guidelines on the CDC Web site, the agency does not recommend routine nasal swab testing because it is not 100 percent effective.

Lucas said the nasal swab is used to interpret results of a group rather than an individual. He said if 100 people working in the same area where anthrax was found are tested and 50 test positive for exposure, the hospital will treat all workers.

Harris said individuals who have been in high-risk areas and feel they may have symptoms should go to the hospital for testing.