WORLD OF MICROBIOLOGY AND IMMUNOLOGY Chagas disease111•
malariafrom the southern United States during World War II.
The Communicable Disease Center began operations in
Atlanta on July 1, 1946, under the direction of Dr. Joseph M.
Mountin.
Initially, the center was very small and was staffed
mainly by engineers and entomologists (scientists who study
insects). But under Mountin’s direction, an expansion program
was begun with the intent of making the center the predomi-
nant United States center of epidemiology. By 1950 the center
had opened a disease surveillance unit that remains a corner-
stone of CDC’s operations today. Indeed, during the Korean
War, the Epidemiological Intelligence Service was created, to
protect the United States from the immigration of disease
causing microorganisms.
Two events in the 1950s brought the CDC to national
prominence and assured the ongoing funding of the center. The
first event was the outbreak of poliomyelitisin children who
had received an inoculation with the recently approved Salk
polio vaccine. A Polio Surveillance Unit that was established at
CDC confirmed the cause of the cases to be due to a contami-
nated batch of the vaccine. With CDC’s help, the problem was
solved and the national polio vaccinationprogram recom-
menced. The other event was a massive outbreak of influenzae.
Data collected by CDC helped pave the way for the develop-
ment of influenzavaccines and inoculation programs.
In the 1950s and 1960s, CDC became the center for
venereal disease, tuberculosis, and immunization programs.
The centers also played a pivotal role in the eradication of
smallpox, through the development of a vaccine and an inoc-
ulation instrument. Other accomplishments include the identi-
fication of Legionnaire’s diseaseand toxic shock syndromein
the 1970s and 1980s, hantavirus pulmonary syndrome in
1993, and, beginning in 1981, a lead role in the research and
treatment of Acquired ImmunodeficiencySyndrome.
In 1961, CDC took over the task of publishing
Morbidity and Mortality Weekly Report. Then as now, the
MMWR is a definitive weekly synopsis of data on deaths and
selected diseases from every state in the United States. A note-
worthy publication in MMWR was the first report in a 1981
issue of the disease that would come to be known as Acquired
Immunodeficiency Syndrome.
Another advance took place in 1978, with the opening
of a containment facility that could be used to study the most
lethal virusesknown to exist (e.g., Ebola). Only a few such
facilities exist in the world. Without such high containment
facilities, hemorrhagic viruses could not be studied, and devel-
opment of vaccines would be impossible.
Ultimately, CDC moved far beyond its original mandate
as a communicable disease center. To reflect this change, the
name of the organization was changed in 1970 to the Center
for Disease Control. In 1981, the name was again changed to
the Centers for Disease Control. The subsequent initiation of
programs designed to target chronic diseases, breast and cer-
vical cancers and lifestyle issues (e.g., smoking) extended
CDC’s mandate beyond disease control. Thus, in 1992, the
organization became the Centers for Disease Control and
Prevention (the acronym CDC was retained).Today, CDC is a world renowned center of excellence
for public health research, disease detection, and dissemina-
tion of information on a variety of diseases and health issues.See alsoAIDS, recent advances in research and treatment;
Bacteria and bacterial infection; History of public health;
Public health, current issuesCEPHALOSPORINS•seeANTIBIOTICS
CChagas diseaseHAGAS DISEASE
Chagas disease is a human infection that is caused by a
microorganism that establishes a parasitic relationship with a
human host as part of its life cycle. The disease is named for
the Brazilian physician Carlos Chagas, who described in 1909
the involvement of the flagellated protozoan known as
Trypanosoma cruziin a prevalent disease in South America.
The disease is confined to North, South, and Central
America. Reflecting this, and the similarity of the disease to
trypanosomiasis, a disease that occurs on the African conti-
nent, Chagas disease has also been dubbed American try-
panosomiasis. The disease affects some 16 to 18 million each
year, mainly in Central and South American. Indeed, in these
regions the prevalence of Chagas disease in the population is
higher than that of the Human Immunodeficiency Virusand the
HepatitisB and C viruses. Of those who acquire Chagas dis-
ease, approximately 50,000 people die each year.
The agent of Chagas disease, Trypanosoma cruzi, is a
member of a division, or phylum, called Sarcomastigophora.
The protozoan is spread to human via a bug known as
Reduviid bugs (or “kissing bugs”). These bugs are also known
as triatomines. Examples of species include Triatoma infes-
tans, Triatoma brasiliensis, Triatoma dimidiata, and Triatoma
sordida.
The disease is spread because of the close proximity of
the triatomine bugs and humans. The bugs inhabit houses, par-
ticularly more substandard houses where cracks and deterio-
rating framework allows access to interior timbers. Biting an
already infected person or animal infects the bugs themselves.
The protozoan lives in the digestive tract of the bug. The
infected bug subsequently infects another person by defecat-
ing on them, often while the person is asleep and unaware of
the bug’s presence. The trypanosomes in the feces gain entry
to the bloodstream when feces are accidentally rubbed into the
bite, or other orifices such as the mouth or eyes.
Chagas disease can also be transmitted in the blood.
Acquisition of the disease via a blood transfusion occurs in
thousands of people each year.
The association between the Reduviid bug and poor
quality housing tends to make Chagas disease prevalent in
underdeveloped regions of Central and South America. To add
to the burden of these people, some 30% of those who are
infected in childhood develop a chronic form of the disease 10womi_C 5/6/03 2:04 PM Page 111