Charles C. Shepard (18 December 1914 – 18 February 1985) was an American microbiologist whose major contribution to the leprosy field was his success in cultivating M. leprae under laboratory conditions, using the mouse foot-pad method.
Shepard first attended Stanford University, but later transferred to Northwestern University, where he earned his B.S., M.S., and M.D. degrees. He worked at the National Institute of Health in Bethesda, Maryland, from 1942 to 1948. He was also chief of the Leprosy and Rickettsia Branch at the Centers for Disease Control and Prevention (CDC) for over 30 years, until his death in 1985.
In 1960, Shepard submitted two important papers: to the American Journal of Hygiene (later to be renamed the American Journal of Epidemiology) and to the Journal of Experimental Medicine. The first was entitled “Acid-Fast Bacilli in Nasal Excretions in Leprosy and Results of Inoculation of Mice” and the second was “The Experimental Disease that Follows the Injection of Human Leprosy Bacilli into Foot-Pads of Mice”. In these papers he recounted the experimental process that led to the multiplication of M leprae in laboratory conditions. Taking his cue from the Australian scientist Frank Fenner, who had cultivated Mycobacterium balnei (later renamed M. marinum) and M ulcerans in the mouse foot pad, Shepard suspected that he could do the same with M leprae. He wrote that this “success in the mouse foot-pad with these two cultivable mycobacterial agents of human skin disease suggested to me that leprosy bacilli might also grow in this environment.” (Shepard)
Shepard had started his experiments in 1957 with M. leprae from the nasal washings of leprosy patients and later also from bacilli collected from skin biopsy specimens. He counted the acid-fast bacilli present in a strip across the diameter of the circle and calculated the number of organisms in the original suspension. He then diluted the suspension and injected it into each right hind foot-pad of 20 mice. The lesions that resulted from inoculation of M. leprae could be seen only under the microscope. This achievement would make it possible to test anti-leprosy drugs, study immunity, and even investigate the possibility of a vaccine.
Outside of the leprosy field, Shepard is best known for his 1977 discovery (with Joseph McDade) of Legionella pneumophila, the causative agent of Legionnaires' disease. He also contributed to the scientific knowledge of other infectious diseases, including typhus and Rocky Mountain fever.
Shepard received many awards in recognition of his research, including the Gorgas Medal (1962), the Kimble Methodology Award (1962), the Philip R. Edwards Award (1964), the World Leprosy Day Award (1970), the first CDC Medal of Excellence (1977), and the Raoul Follereau Award (1978).
In Shepard’s honour, the CDC and the Agency for Toxic Substances and Disease Registry (ATSDR) present the Charles C. Shepard Science Awards for outstanding peer-reviewed research papers published by scientists from these institutions. Additionally, Rollins School of Public Health at Emory University presents the Charles C. Shepard Award annually (since 1986) for scholarly research by a student graduating from the MPH program.
‘History of the Charles C. Shepard Science Award’. Centers for Disease Control and Prevention. Online: http://www.cdc.gov/od/science/aboutus/shepard/history/index.html. Accessed 22 December 2015.
‘Shepard Award’. Rollins School of Public Health. Online: http://www.sph.emory.edu/about/shepard-award/index.html#about Accessed 22 December 2015.
Charles C Shepard, “Acid-Fast Bacilli in Nasal Excretions in Leprosy and Results of Inoculation of Mice,” American Journal of Hygiene 71 (1960): 147-157 and “The Experimental Disease that Follows the Injection of Human Leprosy Bacilli into Foot-Pads of Mice,” Journal of Experimental Medicine 112 (1960): 445-54.
------, “Multiplication of Mycobacterium Leprae in the Footpad of the Mouse,” IJL 30.3 (1962): 291-306.