took to drive from San Francisco to Seattle. Few
infectious diseases today remain localized, though
the risk of infection with them varies widely.
HIV/AIDS, SEVERE ACUTE RESPIRATORY SYNDROME(SARS),
and INFLUENZA stand as stark evidence that
microbes, too, travel the world.
CONTAGIOUS INFECTIOUS DISEASESANTHRAX CHICKENPOX
CHLAMYDIA COLDS
DIPHTHERIA ENCEPHALITIS
GENITAL HERPES GONORRHEA
HEMORRHAGIC FEVERS HEPATITIS
INFLUENZA MEASLES
MENINGITIS MONONUCLEOSIS,
MUMPS INFECTIOUS
RUBELLA SCARLET FEVER
SEVERE ACUTE RESPIRATORY STREP THROAT
SYNDROME(SARS) SYPHILIS
TRICHOMONIASIS TUBERCULOSIS
TYPHOID FEVER
Infectious Diseases in Medical HistoryInfectious diseases have mystified and plagued
humanity for ages. Tuberculosis, smallpox,
cholera, typhoid FEVER, and the plague itself
(“Black Death”) were for centuries the leading
causes of disability, disfigurement, and death.
Mummified remains from ancient Egypt show evi-
dence of smallpox and tuberculosis. Disfigurement
resulting from smallpox was so common through
the 18th century that artists routinely painted por-
traits that discreetly masked or simply did not por-
tray the extensive scars the disease left on the
faces of those who survived the illness. Hip-
pocrates wrote of “phthisis”—Greek for consump-
tion, an apt name for tuberculosis, the disease that
slowly wasted away the lives of those infected.
Manuscript fragments recovered from 7th century
China reference measles. Ancient Greek docu-
ments record outbreaks of “pestilence” that were
likely epidemics of measles, smallpox, and perhaps
plague.
For centuries doctors believed infectious dis-
eases like tuberculosis represented some sort of
inborn weakness in a family because family mem-
bers often had the same illness, generation after
generation. Of course, doctors today know the true
reason such illnesses affected entire families: infec-
tious diseases like tuberculosis spread from person
to person, and living in close contact makes it easier
if not inevitable for them to spread.
The birth of vaccination and the death of a
scourge In the summer of 1796, eight-year-old
James Phipps became the first success story in an
effort that would reach fruition nearly 200 years
later. Country doctor Edward Jenner (1749–1823)
made two scratches on the boy’s arm with a lancet
dipped in the fluid from a smallpox sore. Nothing
happened. Not then, not 14 days later when the
characteristic sores of smallpox should have
started erupting. The scratches healed and James
remained healthy.
Six weeks earlier, Jenner had performed a simi-
lar procedure using the fluid from a cowpox sore,
a much milder form of illness that doctors today
know develops from infection with a virus closely
related to the virus that causes smallpox. Edward
Jenner did not know this but had observed that
milkmaids and farm hands who recovered from
cowpox did not get smallpox. Young James
became ill with cowpox, as Jenner expected he
would, and then soon recovered—also as Jenner
expected he would. Ironically, as an adult James
Phipp nearly lost his life to another infectious dis-
ease endemic throughout history, tuberculosis.
In 1966 the World Health Assembly formalized
a global smallpox eradication program with vacci-
nation, Jenner’s discovery, as its foundation. The
first year of the program, 15 million people
throughout the world contracted smallpox; nearly
a third of them died. Ten years later, on October
26, 1977, Somalian Ali Mao Moallin became the
last person in the world to acquire naturally
occurring smallpox (he survived). In 1980, the
World Health Organization officially declared
smallpox eradicated worldwide and advised coun-
tries to end vaccination programs.
Today vaccination is the cornerstone of infec-
tious disease control and preventive medicine.
Vaccines confer IMMUNIZATIONfor numerous infec-
tious diseases. Many countries, including the
United States, routinely administer set schedules
of vaccines to children, giving them lifelong
immunity that protects them from infection with
diseases such as POLIOMYELITIS, MUMPS, MEASLES,
CHICKENPOX, RUBELLA, PERTUSSIS(whooping COUGH),
and Haemophilus influenzaetype b (Hib).304 Infectious Diseases