The symptoms of the disease include sudden onset of fever, headache, chills, weakness, swollen tender and painful lymph nodes.
The bacteria thrive in the lymph node closest to where it enters the human body. If the growth is not curbed on time, the bacteria an spread to other parts of the body through the bloodstream, causing sepsis, or septicemic plague. If the bacteria affects the lungs, it can cause pneumonia or pneumonic plague. As per the statistics of the World Health Organisation (WHO), if left untreated bubonic plague can cause death in up to 60 per cent of cases.