Microbiology and Immunology

Dysentery WORLD OF MICROBIOLOGY AND IMMUNOLOGY

168

•

entist’s career. “There seemed no reason,” he recalled for

Culhane. “Why should she get [tuberculosis] in this environ-

ment?” After spending two years as a professor of tropical

medicine at Harvard Medical School, Dubos returned to the

Rockefeller Institute to begin a full-scale investigation of

tuberculosis and its causes. Until that time, scientists attempt-

ing to study tuberculosis bacilli had been hindered by the fact

that laboratory methods of cultivation often modified the

organisms to such an extent that they no longer resembled or

behaved like the strains that infected humans. By 1947, how-

ever, Dubos had discovered that by adding a common deter-

gent to the culturemedium, he could raise bacilli so quickly

and in such large quantities that they had little chance to

mutate. This enabled researchers to study the microorganism

more closely and develop the highly effective Bacillus

Calmette-GuÉrin, or BCG, vaccine.

During the course of his research with tuberculosis,

Dubos focused on the importance of heredity, nutrition, phys-

iology, and social and emotional trauma on an individual’s

vulnerability to infection. He used his wife’s case as his first

example. A careful examination of her early health records

revealed that she had suffered from tuberculosis as a child.

Although his wife recovered from the acute attack, Dubos

became convinced that the emotional upheaval of World War

II and her concern for her family’s safety in France had served

to weaken her and reawaken the dormant germ. Some years

later, Dubos’s second wife’s battle with tuberculosis and her

subsequent recovery prompted the couple to collaborate on

The White Plague: Tuberculosis, Man, and Society,a non-

technical account of the disease. Published in 1952, the book

provided additional evidence linking tuberculosis with certain

environmental conditions, such as inadequate nourishment

and sudden economic or social disturbances.

Later, Dubos’s interest in the effects of the total envi-

ronment on human health encouraged him to become involved

with the sociomedical problems of poor communities and to

speak out on the dangers of pollution, as well as social, eco-

nomic, and spiritual deprivation. By 1964, he had become a

leading spokesman for the fledgling environmental movement

and an outspoken critic of what he viewed as the narrow,

short-range approach used by most biologists.

According to Dubos, the problems of technologically

advanced societies posed an equal, if not greater, threat to

human survival. Two of Dubos’s most popular books, Man

Adaptingand So Human an Animal,examine the close rela-

tionship between environmental conditions and man’s physi-

cal, mental, and spiritual development, emphasizing the

dangers inherent in adapting to a polluted, highly mechanized,

highly stressful environment. “Wild animals can survive in

zoos, but only at the cost of losing the physical and behavioral

splendor they possess in their natural habitat,” he wrote in Life.

“Similarly, human beings can survive in the polluted cage of

technological civilization, but in adapting to such conditions,

we may sacrifice much of our humanness.” Dubos also warned

against introducing new substances, such as laundry detergents

containing potentially dangerous enzymes, into the American

marketplace without thorough testing. Unlike many environ-

mentalists, however, Dubos maintained an enormous faith in

both the ability of nature to recover from man’s abuses and

man’s own capacity to recognize and learn from mistakes.

Dubos became a naturalized American citizen in 1938.

Although he maintained a laboratory and an apartment in New

York City, Dubos spent most weekends at his large estate in

Garrison, New York. There, he and his wife planted trees,

raised vegetables, and enjoyed long walks in the scenic

Hudson River Valley. Over the years, Dubos earned numerous

awards for his work, including the Modern Medicine Award,

1961, the Phi Beta Kappa Award, 1963, and the Tyler Ecology

Award, 1976; he also received more than thirty honorary

degrees from various colleges and universities. A member of

professional organizations such the National Academy of

Sciences, Dubos was also appointed by President Richard M.

Nixon in 1970 to serve on the Citizens’ Advisory Committee

on Environmental Quality. Always eager to make his scientific

and philosophical ideas accessible to people from all walks of

life, Dubos continued to write and lecture until shortly before

his death from heart failure at age 82 in New York City.

See alsoHistory of microbiology; History of public health;

History of the development of antibiotics

DDysenteryYSENTERY

Dysentery is an infectious disease that has ravaged armies,

refugee camps, and prisoner-of-war camps throughout history.

The disease still is a major problem in developing countries

with primitive sanitary facilities.

The acute form of dysentery, called shigellosis or bacil-

lary dysentery, is caused by the bacillus (bacterium) of the

genus Shigella,which is divided into four subgroups and dis-

tributed worldwide. Type A, Shigella dysenteriae,is a particu-

larly virulent species. Infection begins from the solid waste

from someone infected with the bacterium. Contaminated soil

or water that gets on the hands of an individual often is con-

veyed to the mouth, where the person contracts the infection.

Flies help to spread the bacillus.

Young children living in primitive conditions of over-

crowded populations are especially vulnerable to the disease.

Adults, though susceptible, usually will have less severe dis-

ease because they have gained a limited resistance. Immunity

as such is not gained by infection, however, and an infected

person can become reinfected by the same species of Shigella.

Once the bacterium has gained entrance through the

mouth, it travels to the lower intestine (colon) where it pene-

trates the mucosa (lining) of the intestine. In severe cases, the

entire colon may be involved, but usually only the lower half

of the colon is involved. The incubation period is one to four

days, that is the time from infection until symptoms appear.

Symptoms may be sudden and severe in children. They

experience abdominal pain or distension, fever, loss of

appetite, nausea, vomiting, and diarrhea. Blood and pus will

appear in the stool, and the child may pass 20 or more bowel

movements a day. Left untreated, he will become dehydrated

from loss of water and will lose weight rapidly. If untreated,

death may occur within 12 days of infection. If treated or if the

womi_D 5/6/03 2:09 PM Page 168