15 February 2013
The first simple test for detecting the presence of
the venereal disease syphilis led to better syphilis control and
other advances in immunology.
The people behind the invention:
Reuben Leon Kahn (1887-1974), a Soviet-born American
serologist and immunologist
August von Wassermann (1866-1925), a German physician and
Syphilis is one of the chief venereal diseases, a group of diseases
whose name derives from Venus, the Roman goddess of love. The
term “venereal” arose from the idea that the diseases were transmitted
solely by sexual contact with an infected individual. Although
syphilis is almost always passed from one person to another in this
way, it occasionally arises after contact with objects used by infected
people in highly unclean surroundings, particularly in the underdeveloped
countries of the world.
It is believed by many that syphilis was introduced to Europe by
the members of Spanish explorer Christopher Columbus’s crew—
supposedly after they were infected by sexual contact withWest Indian
women—during their voyages of exploration. Columbus is reported
to have died of heart and brain problems very similar to
symptoms produced by advanced syphilis. At that time, according
to many historians, syphilis spread rapidly over sixteenth century
Europe. The name “syphilis” was coined by the Italian physician
Girolamo Fracastoro in 1530 in an epic poem he wrote.
Modern syphilis is much milder than the original disease and relatively
uncommon. Yet, if it is not identified and treated appropriately,
syphilis can be devastating and even fatal. It can also be passed from
pregnant mothers to their unborn children. In these cases, the afflicted
children will develop serious health problems that can include
paralysis, insanity, and heart disease. Therefore, the understanding,
detection, and cure of syphilis are important worldwide.
Syphilis is caused by a spiral-shaped germ called a “spirochete.”
Spirochetes enter the body through breaks in the skin or through the
mucous membranes, regardless of how they are transmitted. Once
spirochetes enter the body, they spread rapidly. During the first four
to six weeks after infection, syphilis—said to be in its primary
phase—is very contagious. During this time, it is identified by the
appearance of a sore, or chancre, at the entry site of the infecting spirochetes.
The chancre disappears quickly, and within six to twenty-four
weeks, the disease shows itself as a skin rash, feelings of malaise,
and other flulike symptoms (secondary-phase syphilis). These problems
also disappear quickly in most cases, and here is where the real
trouble—latent syphilis—begins. In latent syphilis, now totally without
symptoms, spirochetes that have spread through the body may
lodge in the brain or the heart. When this happens, paralysis, mental
incapacitation, and death may follow.
Testing Before Marriage
Because of the danger to unborn children, Americans wishing to
marry must be certified as being free of the disease before a marriage
license is issued. The cure for syphilis is easily accomplished
through the use of penicillin or other types of antibiotics, though no
vaccine is yet available to prevent the disease. It is for this reason
that syphilis detection is particularly important.
The first viable test for syphilis was originated by August von
Wassermann in 1906. In this test, blood samples are taken and
treated in a medical laboratory. The treatment of the samples is
based on the fact that the blood of infected persons has formed antibodies
to fight the syphilis spirochete, and that these antibodies will
react with certain body chemicals to cause the blood sample to clot.
This indicates the person has the disease. After the syphilis has been
cured, the antibodies disappear, as does the clotting.
Although the Wassermann test was effective in 95 percent of all
infected persons, it was very time-consuming (requiring a two-day
incubation period) and complex. In 1923, Reuben Leon Kahn developed
a modified syphilis test, “the standard Kahn test,” that was
simpler and faster: The test was complete after only a few minutes.
By 1925, Kahn’s test had become the standard syphilis test of the
United States Navy and later became a worldwide test for the detection
of the disease.
Kahn soon realized that his test was not perfect and that in some
cases, the results were incorrect. This led him to a broader study of
the immune reactions at the center of the Kahn test. He investigated
the role of various tissues in immunity, as compared to the role of
white blood antibodies and white blood cells. Kahn showed, for example,
that different tissues of immunized or nonimmunized animals
possessed differing immunologic capabilities. Furthermore,
the immunologic capabilities of test animals varied with their
age, being very limited in newborns and increasing as they matured.
This effort led, by 1951, to Kahn’s “universal serological reaction,”
a precipitation reaction in which blood serum was tested
against a reagent composed of tissue lipids. Kahn viewed it as a potentially
helpful chemical indicator of how healthy or ill an individual
was. This effort is viewed as an important landmark in the development
of the science of immunology.
At the time that Kahn developed his standard Kahn test for syphilis,
theWassermann test was used all over the world for the diagnosis
of syphilis. As has been noted, one of the great advantages of the
standard Kahn test was its speed, minutes versus days. For example,
in October, 1923, Kahn is reported to have tested forty serum
samples in fifteen minutes.
Kahn’s efforts have been important to immunology and to medicine.
Among the consequences of his endeavors was the stimulation
of other developments in the field, including the VDRL test (originated
by the Venereal Disease Research Laboratory), which has replaced
the Kahn test as one of the most often used screening tests for
syphilis. Even more specific syphilis tests developed later include a
fluorescent antibody test to detect the presence of the antibody to
the syphilis spirochete.
See also: Abortion pill;Antibacterial drugs; Birth control pill;
Mammography; Pap test; Penicillin;
Further Reading :