By Brendan Riley, Associated Press, 10/18/01

ABOUT ANTHRAX Anthrax becomes a weapon when bacteria (shown in top photo as small squiggles) are cultured into spores (larger clumps) and mailed. Anthrax background Anthrax Q & A Facts about anthrax ID tips for suspicious mail  GRAPHICS The disease Types of anthrax Anthrax as a weapon Inside an anthrax attack Disease facts Other bioterror threats Exposure Diagnosing anthrax Anthrax-fighting drugs Cleaning up contamination Suspicious mail What to look for Letters sent to Daschle, NBC  ANTHRAX EXPOSURES See complete list  LATEST NEWS Thousands of workers tested  FROM TODAY'S GLOBE Anthrax hits DC mail worker  REALVIDEO Inhaled anthrax in D.C. N.J. post office contaminated  RECENT COVERAGE 10/21/01 Anthrax in House mailroom N.H. mill was anthrax hot zone Anthrax may be domestic act Mexico rallies ranchers Mail workers receive antibiotics 10/20/01 Anthrax tied to single source Plans made in case of smallpox FBI eyes N.J. neighborhood Sales of Cipro limited 10/19/01 US: Germ was not 'weaponized' NY Post employee has anthrax CDC develops smallpox plan 2d NJ postal worker has anthrax 10/18/01 CBS staffer tests positive No new anthrax at Congress Small anthrax amounts in FL FBI offers $1m reward Anthrax found in Kenya letter Microsoft letter tests negative NJ postal workers has anthrax Pharmacist questioned on Cipro 60 on VT flight get antibiotics Thousands tested in DC 10/17/01 Two Feingold staffers exposed FDA publishes non-Cipro doses Cipro production increased FL, NY anthrax linked Pataki office exposed 10/16/01 Tests under way at ABC FBI: no direct link Man charged with hoax lie Several charged with hoaxes  CDC INFORMATION CDC: www.bt.cdc.gov/Agent /Anthrax/Anthrax.asp Hotline Number: 800-342-3557

CARSON CITY, Nev. -- Final tests on a letter in a Microsoft office in Reno have come back negative for anthrax, Gov. Kenny Guinn announced Thursday.

Tests performed by the Centers for Disease Control and Prevention found the presence of a bacterium, but ruled out that it was anthrax.

The tests performed by the CDC in Atlanta were requested after initial state tests showed anthrax had contaminated a pornographic picture in a letter at the Microsoft Licensing Inc. office in Reno.

The state Health Division's laboratory had confirmed the presence of anthrax earlier, but forwarded the material to the CDC to determine whether it was dangerous or harmless, vaccine-grade anthrax.

The CDC's initial analysis was negative, but state health officials said the first sample sent to the CDC might have been too diluted and sent another.

Six people exposed to the Microsoft letter have tested negative for the deadly, inhaled version of the disease.

Officials at Microsoft Licensing contacted health officials Oct. 10 over an employee's suspicions about a returned envelope, mailed earlier to a vendor in Malaysia. Pornographic pictures had been inserted into the envelope, which also contained a check made out to the vendor, who wasn't identified.

The Malaysian government, which along with the FBI is investigating, says it is not clear where the contamination originated.

Deputy Inspector General of Police Jamil Johari was quoted in the New Straits Times newspaper as saying that the letter from Microsoft in Reno was returned to the sender after the addressee in Malaysia could not be contacted.