Glossary of terms used in the Fred L. Soper exhibit
         March 12,2003

ANOPHELES--A large genus of over 400 species of mosquitoes, approximately two dozen of
which are vectors of malaria. Since the anopheles male does not bite, only the female is
responsible for the transmission of parasites.

CARRIER--An individual who harbors the specific organisms of a disease without manifest
symptoms and is capable of transmitting the infection.

CHENOPODIUM OIL--An anthelmintic (medicine used for controlling parasitic worms)
obtained by distillation of the crushed fruits of Chenopodium ambrosioides that during the early
twentieth century was a primary treatment for ascarids and hookworms in various animals and
humans. Chenopodium oil was usually administered at bedtime, on an empty stomach, and
followed by a laxative, which aided in expelling parasitic worms. It was replaced by more
effective anthelmintics in the 1940s.

CHOLERA--An acute, diarrhea1 illness caused by infection of the intestine with the bacterium
Vibrio cholerue. It is most common in areas near brackish water or areas that have inadequate
sewage treatment. Source of infection is often the consumption of contaminated food or water.
The infection is often mild or without symptoms, but one in twenty infected persons develop
severe cholera characterized by profuse watery diarrhea, vomiting and leg cramps, possibly
leading to dehydration and shock, which can be fatal.

DICHLORODIPHENYLTRICHLOROETHANE (DDT)--The first synthetic organic
pesticide, a chlorinated hydrocarbon (or organochlorine), DDT was discovered in 1939 by a
Swiss chemist Paul Muller. In its early days, it was hailed as a miracle because it was
inexpensive and toxic to a wide range of insect pests, yet appeared to have low toxicity to
mammals. It did not require frequent reapplication and was insoluble, so was not washed off by
rains. It was so effective at killing pests, thus boosting crop yields, and was so inexpensive to
make that its use quickly spread over the globe. It was used for many non-agricultural
applications such as de-lousing soldiers and civilians during World War II, and to control
mosquitoes in residential areas of the United States.

ENDEMIC--When a disease is present or usually prevalent in a population or geographic area at
all times.

EPIDEMIC--Disease outbreaks, especially infectious diseases, which occur suddenly in
numbers clearly in excess of normal expectancy.

EPIDEMIOLOGY--The science concerned with the study of the factors determining and
influencing the frequency and distribution of disease, injury, and other health-related events and
their causes in a defined human population for the purpose of establishing programs to prevent
and control their development and spread.


HOOKWORM--An intestinal parasite of humans that usually causes mild diarrhea and cramps,
but heavy infection can cause serious problems for newborns, children, pregnant women and the
malnourished. Persons are infected when they come into direct contact with soil contaminated
with hookworm larvae, generally through walking barefoot or by accidentally swallowing.

HOST--An individual that harbors or nourishes another organism, such as a parasite.

LARVAE--The newly hatched, wingless, often wormlike form of many insects before
metamorphosis.

MALARIA--A serious, sometimes fatal disease caused by the plasmodium parasite and
transmitted to humans through the bites of infected mosquitoes. Once bitten, the parasites travel
to the victim's liver, enter the liver cells, grow, multiply, and begin attacking the red blood cells.
Symptoms of malaria include a fever and flu-like illness, including shaking, chills, headache,
muscle aches, and tiredness. If untreated, some forms of malaria may cause kidney failure,
seizures, delirium, coma, and death.

PARASITE--An organism that grows, feeds, and is sheltered on or in a different organism while
contributing nothing to the survival of its host.

PARIS GREEN--An extremely poisonous, bright green powder that was used extensively after
the 1870s as an insecticide and which was crucial to the anti-malarial campaigns of Soper and
the Rockefeller Foundation in Brazil during the 1930s. Chemically it is a copper acetoarsenite
that was prepared from arsenic tioxide and copper acetate. Replaced by newer pesticides that
were less toxic to humans, such as DDT, by the 1940s and 1950s.

PLASMODIUM--The genus of the parasite that causes malaria. The genus includes four
species that infect humans: Plasmodium falciparium, Plasmodium vivax, Plasmodium malariae,
and Plasmodium ovale.

TYPHUS FEVER--Louse-borne typhus is the only rickettsial disease that can cause explosive
epidemics in humans. Rickettsia prowazelkii is transmitted by human body lice infected while
feeding on the blood of persons with acute typhus fever. Infected lice excrete rickettsiae when
feeding on a second host. People are infected by rubbing louse fecal matter or crushed lice into a
bite wound, often through scratching. Typhus fever is characterized by the sudden appearance of
headaches, chills, prostration, high fever, delirium, coughing, severe muscle pain, and sensitivity
to light. A rash appears, usually on or near the upper trunk, on the fifth or sixth day of infection
and then spreads to the entire body, except for the face, palms and soles of the feet.

VECTOR--The organism, typically an insect, which transmits an infectious agent to its
alternative host, typically a vertebrate.

YELLOW FEVER-A viral disease caused by the yellow fever virus and transmitted to humans
through the bites of infected mosquitoes. The virus remains silent during an incubation period of
three to six days. This is followed by two distinct disease phases. The first, or "acute," phase, is
normally characterized by fever, muscle pain, headache, chills, high fever, loss of appetite,

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nausea, and/or vomiting. After three or four days most infected persons improve and symptoms
disappear. Approximately one in five infected persons enter the second, or "toxic," phase within
twenty-four hours. The patient rapidly develops a fever, jaundice, and abdominal pain with
vomiting. Bleeding might occur from the mouth, nose, eyes and/or stomach. Blood may appear
in the vomit or feces. Kidney function deteriorates and may fail entirely. Half of patients who
enter the "toxic" phase die within ten to fourteen days.

R. Dennis Pool
Research Assistant, Digital Manuscripts Program
National Library of Medicine