how does yersinia reproduce? In most countries of Africa, Asia, and South America where plague is reported, the risk of exposure exists primarily in rural mountainous or upland areas. Following natural disasters and at times when regular sanitary practices are interrupted, plague can extend from its usual areas of endemicity into urban centers. Rarely, pneumonic plague has been reported in conjunction with outbreaks of bubonic plague, and tourist travel to areas with reported cases of plague should be avoided. look at http://www.bacteriamuseum.org/species/yp... this may be the best place to anser any q's you have about this | 