ABSTRACT
Most epidemics occur as a result of various factors, but the mechanisms that trigger them are not entirely clear. Modern epidemiology acknowledges that geomorphological elements play an important part in the transmission of epidemics. The epidemics recorded in the catalogue fall into two categories: those whose outbreak is causally related by the sources to external factors and those that seemingly broke out without any cause, suddenly and unexpectedly. The common symptoms of the two epidemics include elevated skin lesions all over the body of the victims and loss of sight as a result of the infection. The epidemic probably broke out in the Orient and was brought back by the armies under Lucius Verus in Persia and mainland Asia Minor. Shigellosis is a bacterial disease with world-wide distribution. Humans are highly susceptible to it. Its incubation period ranges from 36 to 72 hours.
