Transmission Human Yersinia infections most commonly result from the bite of an infected flea or occasionally an infected mammal, but like most bacterial systemic diseases, the disease may be transmitted through an opening in the skin or by inhaling infectious droplets of moisture from sneezes or coughs. In both cases<unk>  need not be the result, and in particular, not the initial result, but it occasionally happens that bubonic plague for example leads to infection of the blood, and<unk>  results. If the bacteria happen to enter the bloodstream rather than the lymph or lungs, they multiply in the blood, causing bacteremia and severe sepsis. In<unk> , bacterial endotoxins cause disseminated intravascular coagulation (DIC), where tiny blood clots form throughout the body, commonly resulting in localised ischemic necrosis, tissue death from lack of circulation and perfusion. DIC results in depletion of the body's clotting resources, so that it can no longer control bleeding. Consequently, the unclotted blood bleeds into the skin and other organs, leading to red or black patchy rash and to hematemesis (vomiting blood) or hemoptysis (coughing up blood). The rash may cause bumps on the skin that look somewhat like insect bites, usually red, sometimes white in the center.<unk>  is caused by horizontal and direct transmission. Horizontal transmission is the transmitting of a disease from one individual to another regardless of blood relation. Direct transmission occurs from close physical contact with individuals, through common air usage, from direct bite from a flea or an infected rodent. Most common rodents may carry the bacteria and so may Leporidae such as rabbits: right Significant carriers of the bacteria in the United States include: - Rats - Prairie dogs - Squirrels - Chipmunks - Rabbits - Fleas The bacteria are cosmopolitan, mainly in rodents in all continents except Australia and Antarctica. The greatest frequency of human plague infections occurs in Africa. The bacteria most commonly appear in rural areas and wherever there is poor sanitation, overcrowding, and high rodent populations in urban areas. Outdoor activities such as hiking, camping, or hunting where plague-infected animals may be found, increase the risk of contracting<unk> , and so do certain occupations such as veterinary or other animal-related work.
Septicemic plague
Urban plague
Bubonic plague
Hittite plague
Metal fume fever
Sylvatic plague
Tomato fever
Pneumonic plague