Today the term cholera is restricted to suspected infections caused by Vibrio cholerae, sometimes called Asiatic cholera. Vibrio cholerae produces a very characteristic watery diarrhea sometimes described as ‘rice water’. This narrow definition wasn’t always so.
Since antiquity, cholera could refer to any diarrhea or dysentery. The term cholera comes from the Greek word cholē meaning bile. Cholera then was a flushing of bile from the body in an attempt to rebalance Galen’s four humors of the body (blood, bile, black bile, and phlegm) .
In 19th century American medical records, it is common to see three types of cholera reported: cholera morbus, cholera infantum, and Asiatic cholera. Cholera morbus and cholera infantum were both terms for non-specific diarrhea and/or dysentery in adults and children under age five respectively. Cholera morbus was sometimes called the summer complaint and was usually found in older children and adults from July to September . It was caused by a variety of gastrointestinal pathogens with a significant contribution from contaminated food. Cholera infantum was given as the primary cause of death in children under age five in 19th century Illinois . Physicians specifically associated it with the ages of teething and finger foods. Even given its non-specific definition, it was still probably over diagnosed due to paradigms of childhood illness. For example, early Illinois physicians did not believe that children could contract malaria, then endemic in Illinois. Asiatic cholera is caused by Vibrio cholerae, epidemic in Illinois in 1832-1834, 1838, 1849-1852, 1866-1867, and 1892 . Apart from discrete epidemic waves, Asiatic cholera was uncommon in America.
 Männikkö, N. (Ed) (2011). Etymologia: Cholera. Emerging Infectious Disease, 17 (11) http://dx.doi.org/10.3201/eid1711.ET1711
 Rawlings, Issac D. et al. (1927).The Rise and Fall of Disease in Illinois. State Department of Health.
The new issue of Emerging Infectious Diseases has little piece on the etymology (origins) of the genus name Yersinia. The genus Yersinia is best known for its first member, Yersinia pestis, better known as the plague or bubonic plague. The name Yerisnia is not very old. The genus was renamed Yersinia after one of its discovers Swiss microbiologist Alexandre-Émile-John Yersin (1863-1943), from its original Pasturella, in the 1970s.
Yersin lived in the great age of the microbe hunters, young men who went out into epidemics in developing countries with the primary purpose of identifying new pathogens. Yersin did his homework studying medicine in Paris and working under Robert Koch in Germany on tuberculosis, Rene Roux on rabies and rounding out his study at the Pasteur Institute in Paris. From there he took a job with at French shipping company that would bring him experience with unknown infectious diseases in southeast Asia.
Yersin was one of the microbe hunters who converged on Hong Kong during an outbreak of plague in 1894. Within a week, he had isolated the bacterium that he believed responsible for the outbreak and named it Pasteurella pestis, presumably after the Pasteur Institute. Japanese microbiologist Shibasaburo Kitasato also isolated the same bacterium during the same outbreak of the plague. Both men rapidly published their findings; Yersin in French and Kitasato in English and Japanese. There has been some tension over who actually discovered the plague bacterium.
Yersin went on to continue his study of plague in search of a vaccine for many years. Late in his life he established a laboratory in his adopted country, Vietnam, where he completed his work on a plague antiserum. Yersin’s antisera is reputed to have cut the mortality rate from 90% to about 7%.
Later at least twelve members of the Yersinia genus were discovered. It is currently believed that Yersinia pestis evolved from Yersinia pseudotuberculosis.
Reference: “Entymologia: Yersinia” Emerging Infectious Diseases, March 2010, 16 (3).