Alice Catherine Evans Biography (1881-1975)

Nationality
American
Gender
Female
Occupation
microbiologist

Evans was born in Neath, Pennsylvania, on January 29, 1881. After completingher primary education and studying for one year at the Susquehanna Institutein Tonawanda, she began teaching in a local elementary school. Four years later, she decided to pursue a college education and entered Cornell Universityfor a two-year nature study course. She became so interested in science thatshe decided to remain at Cornell for a bachelor of science degree in agriculture.

With the support of her bacteriology professor at Cornell, Evans received a scholarship to the University of Wisconsin and, in 1910, received a master's degree from that institution. She often thought about studying for a doctoraldegree, but became so involved in her own research that she never attained that goal.

After graduation from Wisconsin, Evans accepted a research job with the Department of Agriculture, working first in Wisconsin and later in the Dairy Division Laboratories in Washington, D.C. One of her early projects was the studyof bacteria in dairy products. She was intrigued to discover a close similarity between two types of bacteria, Bacillus abortus and Micrococcusmelitensis. The former caused spontaneous abortions in cows and was not thought to be transmitted to humans. The latter organism caused a disease in humans originally known as Malta fever, but latter referred to as undulating fever.

Evans' research was of significance for two reasons. First, spontaneous abortion among cows was a serious problem for the dairy industry. The developmentof a vaccine for B. abortus eventually proved to be of enormous benefit to the industry. Second, the similarity of B. abortus to M. melitensis raised the possibility that, popular opinion to the contrary, harmful bacteria might be transferred from cows to humans.

In 1918, Evans discovered the first confirmed case in which brucellosis--a common disease in cows--was transmitted to humans. The agent responsiblewas yet a third microorganism, Brucella suis. Evans was able to demonstrate that this serious disease in cows could be transmitted to humans. Bacteriologists were at first dubious of Evans's work. Some rejected her findingson irrelevant grounds: that she was a woman or that she had no Ph.D., but others wondered how the transmission of brucellosis from cow to human had escaped scientists' notice for so long.

Gradually the answer to that question became clear. First, Evans began to collect more and more reports of brucellosis in humans from countries around theworld. Apparently the disease was more common than anyone had imagined. Second, she discovered that the disease can occur in two forms: acute, inwhich the symptoms occur quickly and are easy to recognize, and chronic, in which symptoms develop slowly and over many years. It soon became obvious that chronic brucellosis was relatively common among families exposed to raw milk, but that it was typically diagnosed as another condition.

Evans herself developed chronic brucellosis as a result of her research. Sheexperienced a number of devastating attacks of the disease, but survived themall. She lived a long and productive life, serving in 1928 as the first female president of the American Society for Microbiology. She died in Alexandria, Virginia, on September 5, 1975, at the age of 94. As a result of her work,vaccination of cows and pasteurization of milk are now routine and are responsible for dramatic declines in both bovine and human diseases.

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