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Then & Now


Then & Now: Epidemics Panels

“When we train students who return to their countries, we have an exponential impact on health.”

—JHSPH Dean Michael J. Klag, MD, MPH ’87

Sparked by microscopic pathogens, diseases like influenza can explode in communities, tear through populations and sweep across the globe.

Others like malaria can exact a relentless toll on humanity over millennia. Regardless of their speed, diseases like bubonic plague, smallpox, malaria, HIV/AIDS and tuberculosis have left devastation in their wake and profoundly shaped the history of civilizations.

Against the constant threat of disease epidemics, public health emphasizes prevention and evidence-based, population- level solutions. Since its founding in 1916 as the world’s first independent, degree-granting school of public health, the Johns Hopkins Bloomberg School of Public Health has marshaled researchers, teachers, practitioners, policy leaders and students to envision and create the strongest possible human defenses against disease. The future demands public health science that relentlessly innovates, drives discovery and strengthens humanity’s resilience in a world of constantly emerging threats.




The Johns Hopkins School of Hygiene and Public Health (JHSPH) establishes the world’s first Department of Immunology. Its chair, William Henry Welch, was also the School’s first dean who was commissioned as a lieutenant colonel in the U.S. Army Medical Corps after the U.S. entered World War I.

1918 - The first case of H1N1 influenza is reported by an Army private at Fort Riley, Kansas


The first case of H1N1 influenza is reported by an Army private at Fort Riley, Kansas, sparking the Great Influenza Pandemic, which killed more than 50 million people worldwide within six months.



The School establishes the first Department of Epidemiology in the world, headed by Wade Hampton Frost, who had conducted field investigations of typhoid and polio epidemics for the Public Health Service Hygienic Laboratory.



JHSPH establishes the Department department of virology, headed by Charles Simon. Because viruses are much smaller than bacteria, victory over polio and other viruses requires new lab techniques and equipment.

One-square-mile model research and training area


The School and Baltimore City Health Department (BCHD) establish a one- square-mile model research and training area, the Eastern Health District, for intensive epidemiological research.

1948 - The electron microscope is introduced


The electron microscope is introduced and first used at the School by faculty that include polio researcher Isabel M. Morgan in Epidemiology, and Pathobiology chair Frederik Bang.

1952 - David Bodian


The School’s David Bodian and Dorothy Horstman at Yale independently prove that poliovirus travels from the digestive tract to the bloodstream, and then to the nervous system.

1980 - After D.A. Henderson, MD, MPH ’60, leads a decade-long, global campaign against smallpox


After D.A. Henderson, MD, MPH ’60, leads a decade-long, global campaign against smallpox, WHO declares it vanquished, the first disease to be eradicated worldwide. Henderson serves as Dean of the School from 1977 to 1990.





Alfred Sommer, MD, MHS ‘73, discovers that inexpensive vitamin A can reduce child mortality in the developing world by up to 33 percent. Sommer serves as Dean of the School from 1990 to 2005.

2001 - Michael R. Bloomberg


With a major grant from the Bloomberg Philanthropies, Diane Griffin, chair of the W. Harry Feinstone Department of Microbiology and Molecular Immunology, founds the Johns Hopkins Malaria Research Institute.


2010 - Carlos Castillo-Salgado, MD, JD, DrPH ‘87


Carlos Castillo-Salgado, MD, JD, DrPH ‘87, in Epidemiology helps to establish the field of spatial epidemiology, which uses high-tech mapping technologies such as Geospatial Information Systems (GIS). 


Then & Now

Then: Influenza - 1918 Seattle Police

Then: Influenza

WHEN THE JOHNS HOPKINS SCHOOL OF HYGIENE AND PUBLIC HEALTH opened its doors for classes in October 1918, the world was in the midst of one of the deadliest pandemics in human history. The Great Influenza Pandemic, whose spread was exacerbated by troop movements in World War I, ultimately killed at least 50 million people. That strain of H1N1 influenza killed otherwise healthy young adults in a matter of days.

At the time, the School’s first dean, William Henry Welch, was called to serve on the U.S. Army Surgeon General’s staff. As he gathered an elite corps of scientific researchers and physicians to fight influenza, Welch almost died after he became infected while inspecting military hospitals. Also joining the fight was Wade Hampton Frost, founding chair of Epidemiology from 1919 to 1938, who embarked on a massive epidemiological study of the pandemic in 18 U.S. communities. Frost’s research, among the earliest work to be published on the pandemic, provided public health experts with vital insights.

The battle begun by Welch, Frost and others at the School continues today, spearheaded by Andrew Pekosz, co-director of the Johns Hopkins Center of Excellence in Influenza Research and Surveillance. Researchers at the Center—one of five nationwide— are investigating influenza’s constantly changing nature in order to develop strategies to lessen the impact of future pandemics. 


Now: Ebola

Now: Ebola

FIRST RECOGNIZED in Sudan and the Democratic Republic of the Congo (Zaire) in 1976, Ebola hemorrhagic fever brings horror to the human body. It begins with a sudden onset of fever, fatigue and headache and can progress quickly to vomiting, bleeding from the eyes and ears, and organ failure. Spread initially by contact with infected animals and then with human bodily fluids, Ebola resurfaced in late 2013 in West Africa and killed close to half of its victims. Because of its shocking symptoms, ease of transmission and high death toll, the disease provoked widespread panic.

The Bloomberg School responded quickly with expert assistance. Working with international, domestic and other Hopkins institutions, the School created training materials for local health workers, connected caregivers with resources, coordinated behavioral interventions and advised UNICEF and health ministries on managing the outbreak and rebuilding health systems. The School’s Center for Communication Programs provided lifesaving, behavior-change messaging for the public. While some School faculty helped train health workers, others would later use advanced computer modeling to document the human cost of the diversion of resources to Ebola from efforts against other deadly diseases like measles.

A Closer Look

A Closer Look - Tolbert Nyenswah, LLB, MPH ’12

Knowledge and Leadership Defeat Ebola

During the worst of the Ebola epidemic in Liberia, bodies lay in the streets. Patients streamed into clinics. Health care workers were unprepared and unprotected. And families continued hands-on preparation of loved ones for burial, hastening the epidemic’s spread.

“It was a catastrophe,” said Tolbert Nyenswah, LLB, MPH ’12, Liberia’s deputy minister of Health and Social Welfare, who was appointed to direct the country’s response to a terrifying and unprecedented outbreak. Faced with the challenge of a lifetime, he worked with international health agencies to coordinate Liberia’s response. He enlisted fellow citizens and multinational resources to increase treatment units and laboratories, mobilize communities, isolate the sick, track their contacts and add burial teams to remove contagious corpses. Because misinformation was a major barrier to bringing the disease under control, he led a communications campaign to ease fears and promote behavior change.

“We had to work very hard to engage the affected communities, to educate them and gain their trust as we scaled up our response,” Nyenswah said. “That took time and patience.” He instituted nationwide training for the health care workforce and smoothed logistics to get supplies to health facilities. After methodically tracing Ebola patient contacts and isolating each of them for 21 days, Nyenswah and his colleagues began to see the disease abate. 

Display Credits

Main Illustration

  • Brad Yeo


  • 1917 The Alan Mason Chesney Medical Archives of The Johns Hopkins Medical Institutions
  • 1918 National Museum of Health and Medicine
  • 1919 Evan Oto/Science Source
  • 1925 The Alan Mason Chesney Medical Archives of The Johns Hopkins Medical Institutions
  • 1927 The Alan Mason Chesney Medical Archives
  • 1932 Mitchell's New General Atlas, 1864 Edition
  • 1938 Public domain, from National Library of Medicine
  • 1939 The Alan Mason Chesney Medical Archives of The Johns Hopkins Medical Institutions 
  • 1941 U.S. National Library of Medicine
  • 1942 U.S. National Library of Medicine
  • 1944 Public domain, from National Library of Medicine
  • 1945 Chris Myers, object courtesy of Alan Chesney Medical Archives
  • 1946 U.S. National Library of Medicine
  • 1947 U.S. National Library of Medicine
  • 1948 U.S. National Library of Medicine
  • 1949 U.S. National Library of Medicine
  • 1951 Copyright/iStock/chargerv8
  • 1952 The Alan Mason Chesney Medical Archives of The Johns Hopkins Medical Institutions
  • 1955 Public domain, from National Library of Medicine
  • 1959 The Alan Mason Chesney Medical Archives
  • 1963 Copyright/iStock/FabianCode
  • 1971 Saving Lives Millions at a Time, JHSPH
  • 1980 The Alan Mason Chesney Medical Archives
  • 1982 The Alan Mason Chesney Medical Archives
  • 1984 Roger Harris/Science Source
  • 1985 JHSPH archives
  • 1986 JHSPH archives
  • 1987 SDYM
  • 1988 Copyright/iStock/Cesar Okada
  • 1989 Doug Martin/Science Source
  • 1990 Chiang Mai University, Thailand
  • 1991 Roger Harris/Science Source
  • 1997 Chris Hartlove
  • 2001 JHSPH
  • 2009 JHSPH International Vaccine Access Center
  • 2010 courtesy of Carlos Castillo-Salgado (photo subject)
  • 2011 Chris Hartlove
  • 2012 Barbara Rios/Science Source
  • 2013 Copyright/iStock/Chelovek
  • 2014 courtesy of Johns Hopkins Biomedical Engineering
  • 2015 Copyright/iStock/maska82

Then and Now

  • Then: 1918 photo of Seattle Police: Courtesy of the American National Red Cross. 1918. All rights reserved in all countries.
  • Now: Ebola Photo: Getty Images AFP Photo/Dominique Faget

A Closer Look

  • Tolbert Nyenswah: Chris Hartlove