View in other NatureServe Network Field Guides
	
		NatureServe
		
		Montana
		Utah
		Wyoming
		Idaho
		Wisconsin
		British Columbia
		
		South Carolina
		Yukon
		
		California
		New York
	
	
 
		
		 
     
	
		Plague bacterium - Yersinia pestis
		
		
		
		
	 
	
	 
		General Description
		Yersinia pestis is a Gram-negative rod-shaped bacterium that is the cause of the infectious disease known as plague.
		
	
	
	Species Range
	
		
			Montana Range
		Range Descriptions
			 
			
			
				
					 Non-native
					Non-native
				 
			
				
					
			 
			
		 
		
	 
	
    		Range Comments
			The bacterium Yersinia pestis is believed to have originated in central Asia (Achtman et al. 2004 In Biggins 2010), but is now present world-wide.  The bacterium is a fairly recent introduced species to North America. The first cases of plague in the United States were in coastal area including Los Angeles, San Fransisco, and Seattle.  Plague was not reported in the United States until the late 1890's and early 1900's (Link 1955). It is believed that Yersinia pestis eventually reached and spread throughout the native rodent population.  It reached it's current distribution by 1950.  In North America, plague is found from the west coast to the Great Plains and from southwestern Canada to Mexico (CDC 2009).
			
		
		Observations in Montana Natural Heritage Program Database
		Number of Observations: 35
		
		
(Click on the following maps and charts to see full sized version)
		Map Help and Descriptions
		
		
		 
		
			
				 
			
				 (Observations spanning multiple months or years are excluded from time charts)
			
			(Observations spanning multiple months or years are excluded from time charts)
		 
		
			
		
		
	
		Stewardship Responsibility
		
		
	
		Threats or Limiting Factors
		Even though the common reservoir host for the plague bacterium is usually rodents, it is the infector (fleas) that actually transmits it between hosts. Plague can be transmitted to humans via contact with or biting of infected fleas, as well as contact with infected mammals. No confirmed case of human-to-human plague has been documented in the United States since 1925.
Over 200 mammalian species have been documented contracting plague, including the Montana Species of Concern Black-tailed Prairie Dog, White-tailed Prairie Dog and Black-footed Ferret (PHAC 2001).
References
	
		
			
			
			- Web Search Engines for Articles on "Plague bacterium"