[Emerging Infectious Diseases]                                                         
[Volume 4 No. 3 / July - September 1998]

Special Issue

Emerging Infectious Diseases: A Brief Biographical Heritage

D. Peter Drotman
Centers for Disease Control and Prevention, Atlanta, Georgia, USA

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The concept that infectious (and other) diseases emerge and reemerge is not
new, and neither is the search for causes of disease emergence. However,
societies frequently overlook or forget that microbes evolve, adapt, and
emerge in response to nonmicrobial and even nonbiologic changes in the
physical and social environment. Sometimes we need to be rudely reminded of
this lesson. Two scientists who have delivered such reminders, both in the
form of landmark reports, are Rudolf Virchow, a 19th century German
pathologist, statesman, and anthropologist, and Joshua Lederberg, the
American microbiologist who coined the phrase "emerging infectious
diseases" within the last decade (Photo). We owe much to the pioneering
vision of these scientists.

[Photo/Fig] Rudolf Virchow and Joshua Lederberg

Infectious diseases have been emerging for at least as long as humans have
inhabited the earth. Every student of microbiology, medicine, and public
health learns about the triangle of host, environment, and agent; what is
not clear is how the three change over time, often in response to changes
in another side of the triangle. Factors that influence such changes do
evolve, but many are surprisingly constant. How easily and often some of
these factors are overlooked is often both consequential and tragic; a
historical example illustrates this point.

Rudolf Virchow, the founder of cellular pathology, wrote the first textbook
in that field and established the principle that disease results from
disturbed cellular function. As a young physician and anatomic pathologist
in Berlin, he was assigned by the central government to investigate an
epidemic in Upper Silesia, a sector of the Prussian Empire populated by a
Polish-speaking minority. He completed the field portion of his
investigation on March 10, 1848 (exactly 150 years before the International
Conference on Emerging Infectious Diseases). The report he wrote was
remarkable.

Even though Virchow was working before the germ theory of disease was 
accepted, at a time when disease causation was highly debated and microbes
were not well described, he seems to have correctly diagnosed typhus (or possibly
relapsing fever) as the cause of the Silesian epidemic (1). Even though 
Virchow's diagnosis cannot be confirmed, it is consistent with clinical
descriptions and epidemiologic inference. He clearly demonstrated that the 
conditions and vectors for typhus and relapsing fever (famine and malnutrition,
humid climate, poor housing, poverty) were present in Upper Silesia in 1847 
to 1848. The agents that cause epidemic louse-borne typhus fever (Rickettsia
prowazekii) and relapsing fever (Borrelia recurrentis) were not described 
until many years later.

[photo]
Virchow's report was a scathing criticism of the Prussian government, which
he squarely blamed for the epidemic. Virchow considered the Silesian
outbreak investigation a defining episode in his life and career, so when
the government largely ignored the report and his recommendations (Table
1), he became a passionate voice in politics, albeit in a minority role. He
died in 1902, a revered scientist with a lifetime of magnificent
achievements, but also with desires to have done more to improve public
health and social conditions. We still have a lot to learn from Virchow's
life and work.

Joshua Lederberg was awarded the Nobel Prize for medicine in 1958 for his
discoveries concerning genetic recombination and the organization of the
genetic material of bacteria. He is President Emeritus of The Rockefeller
University in New York, a member of the Institute of Medicine, an advisor
to presidents, and a 20th century Rudolf Virchow. Like Virchow, Lederberg
recognized that microscopic changes make much larger differences,
particularly when viewed in the context of global changes. Like Virchow, he
coauthored a prescient report that associated a pressing health emergency
with larger social, political, and environmental changes. The similarities
between the two reports are striking (Tables 1, 2). Each regarded control
of diseases as primarily social, political, and environmental. We overlook
this common theme at our collective peril.

Unlike Virchow's report, the words of Joshua Lederberg are being translated
into actions. Those actions can be spurred by disseminating information and
building partnerships to effectively address the ongoing threat of emerging
infectious diseases.

 
Table 1. Virchow's recommendations to the Prussian government regarding
 the typhus epidemic in Upper Silesia, 1848 (2)
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 Political reform and local self-government, including local coordination
 of relief efforts

 "Education, with its daughters, liberty and prosperity" (3)

 Economic reform

 Agricultural reforms, including development of cooperatives

 Building of roads

 Acceptance of Polish as an official language (while most Silesians spoke
 Polish, nearly all the physicians and school teachers assigned by the
 central government spoke only German)

 Separation of church and state (he criticized the Catholic hierarchy) (4)

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             Table 2. Factors in disease emergenceThe
             Institute of Medicine's 1992 report on emerging
             infections (5)

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                    Human demographics and behavior

                    Technology and industry

                    Economic development and land use

                    International travel and commerce

                    Microbial adaptation and change

                    Breakdown of public health measures

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References

  1. Eisenberg L. Rudolf Ludwig Karl Virchow: Where are you now that we
     need you? Am J Med 1984;77:524-32.
  2. Silver GA. Virchow, the heroic model in medicine: Health policy by
     accolade. Am J Public Health 1987;77:82-8.
  3. Virchow RL. Report on the Typhus Epidemic in Upper Silesia. Translated
     in: Rather LJ, editor. Rudolf Virchow: Collected Essays on Public
     Health and Epidemiology, 2 vols. Canton (MA): Science History
     Publications 1985:311.
  4. Taylor R, Rieger A. Medicine as a social science: Rudolf Virchow on
     the typhus epidemic in Upper Silesia. Int J Health Services
     1985;15:547-59.
  5. Lederberg J, Shope RE, Oaks SC, editors. Emerging Infections:
     Microbial Threats to the United States. Washington: National Academy
     Press, 1992.

Emerging Infectious Diseases
National Center for Infectious Diseases
Centers for Disease Control and Prevention
Atlanta, GA

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