[4] Between the ages of five and six, Evans was taught at home by her parents and then attended a one-room school house in Neath, where she earned outstanding grades.

[7] After four years of teaching, she took a free course for rural teachers at Cornell University meant to help them inspire their students to love science and nature.

Cornell offered bacteriology for free tuition in order to encourage students to pursue the still-new science.

[7] Evans was offered a federal position at the Dairy Division of the Bureau of Animal Industry at the United States Department of Agriculture.

She worked on refining the process of manufacturing cheese and butter for improved flavor and investigating the sources of bacterial contamination in milk products.

She was the first woman scientist to hold a permanent position as a USDA bacteriologist[9] and as a civil servant, was protected by law.

[5] Each year, Evans took one undergraduate university course, learning German in order to read research reports (prior to World War I, Germany led bacteriology).

[3] She was met with skepticism, particularly because she was a woman and did not have a Ph.D.[1] After publishing, Evans decided to let the issue rest, knowing that her findings would be tested and verified with time.

[7] Evans joined the United States Public Health Service's Hygienic Laboratory in April 1918 to study epidemic meningitis, which was "one of the dread diseases of World War I.

[7][4] When soldiers returned from World War I and Streptococcus spread throughout the shanties and tents they lived in, Evans changed her focus again.

She reached out to William H. Welch, who was the Dean of the School of Hygiene and Public Health of the Johns Hopkins University, to aid in her communications with Smith.

Six months after Smith responded to a letter from Welch, asking Evans to suspend "judgment until the unknown factors responsible for or contributing to the incidence of the human cases have been brought to light," Evans was invited to sit on the National Research Council's Committee on Infectious Abortion, which was chaired by Smith.

[7] At the Hygienic Laboratory, Evans was infected with undulant fever in October 1922, a then-incurable disease that impaired her health for twenty years.

In 1928, in recognition of her achievement, the Society of American Bacteriologists elected Evans as their president, making her the first woman to hold the position.

With the advent of disability insurance, the literature began suggesting malingering as a cause for failing to recover from brucellosis, so Evans encouraged further study into the disease.