Approximately 10 to 20 people in the United States develop plague bacteria infections each year from flea or rodent bites -- primarily from infected prairie dogs -- in rural areas of the southwestern United States. For each seven people that are infected with plague, about one person dies. There has not been a case of person-to-person infection in the United States since 1924.
Worldwide, there have been small plague outbreaks in Asia, Africa, and South America. Globally, the World Health Organization (WHO) reports 1,000 to 3,000 cases every year. Current WHO statistics show that worldwide, there were 2,118 cases in 2003.
Plague bacteria infections occur more frequently during spring and summer months, especially in males and people under the age of 20.
(Click Where Is Plague? for more information.)
Bioterrorism is a real threat to the United States and around the world. Pneumonic plague can occur through aerosol distribution. Plague bacteria are widely available in microbiology banks around the globe, and thousands of scientists have worked with it, making a biological attack a serious concern. However, the United States does not currently expect a plague attack.