WASHINGTON -- A disease that can sicken cattle and cause them to abort their calves is nearly eradicated in all 50 states, according to the Department of Agriculture.

Considered one of the most serious livestock diseases, brucellosis is a contagious disease that can spread from animals to humans. Its main threat is to cattle, bison and swine -- causing decreased milk production, infertility, lameness and loss of young. There is no known treatment for the disease.

The Department of Agriculture announced that Texas was the last state to become "brucellosis free" last week, saying it is the first time in 74 years that all states, Puerto Rico and the Virgin Islands have reached that status for commercial herds.

Still, the disease could pose threats in the West, where the presence of brucellosis in free-ranging bison and elk in Yellowstone National Park and Grand Teton National Park could affect herds in surrounding states.

If brucellosis is found in more than one herd of cattle in a brucellosis-free state within two years, the state loses its brucellosis-free status and may face restrictions on interstate cattle movement. Montana discovered the disease in a herd in May 2007.

"Our work is not done," said Bruce Knight, agriculture undersecretary for marketing and regulatory programs. "We must now focus our efforts on eradicating brucellosis from the free-ranging elk and bison populations in the greater Yellowstone area in order to protect our national cattle herd against future outbreaks."