Page 31 - parasitology for medical and clinical laboratoryprofessionals

Background of Parasitology 11

Then, as civilization advanced, the slave trade most fact that some of the most important parasites we find
likely began before recorded history and in biblical times. today, the helminth worms along with their ova and the
This resulted in indigenous populations that might have protozoa, can now be found in ancient preserved stool
been subjugated during war before being transported to specimens, lending verification to what was previously
unfamiliar areas of the world but living in close proxim- only educated guesses or theory.
ity to a genetically different population. Around 1500, The presence of helminth eggs and protozoan cysts
the Spaniards sometimes enslaved groups of Native have been found in preserved stools called coproliths, a
Americans as the first in the New World to be enslaved. term that literally means “fecal stones” or remnants of the
Then shortly thereafter, African slaves who might have products of bowel elimination that are stone-like. These
been captured by other tribes and were sold into slavery fecal samples have become fossilized or desiccated
were transported to the New World, which included the (dried) as they are hundreds and even thousands of years
Caribbean islands, from the Old World. More recently in age. These bits of hardened feces often contained nat-
the spread of the Human Immunodeficiency Virus urally preserved bodies of parasites that had infested the
(HIV), and the development of AIDS (Acquired Im- gastrointestinal tract of these ancient peoples. Spring-
munodeficiency Syndrome) from HIV infections, most ing from these studies is a new branch of science called
likely originated on the African continent. This disease paleoparasitology. This helps to extend the knowledge
serves to initiate immunodepression associated with base that previously had been more theory than fact. It is
these conditions and has spread to the rest of the world possible that less evolved versions of some parasites seen
in great numbers. today may be found in preserved remains of animals and
This condition predisposes the person suffering humans and the excrement of each. Examples of some
from AIDS to becoming infected with a variety of oppor- of these discoveries will be discussed later. So vast is the
tunistic parasitic organisms. It has been proposed and field of human parasitology, and with this new and far-
not disproven that this ravaging disease originated in the reaching evidence and the discoveries made to date from
green monkeys of Africa, as these animals were widely the past, the amount of data will no doubt grow dramati-
hunted for food, often resulting in contact with the ani- cally in the future.
mal’s blood and body fluids. It should be kept in mind Written documents related to parasitic infection in
that the origins of the disease are still in dispute, and has ancient Egypt from several thousand years BC exist. An-
led to various theories over the years since the advent cient medicine men were apparently aware of parasitic
of the disease. The syndrome (group of symptoms) of infections, as described in the Ebers papyrus of 1500 BC
AIDS has resulted in the establishment of a number of discovered at Thebes. Somewhat later, Greek physicians
new opportunistic parasitic infections that cover the in the years from 800 to 300 BC described symptoms
entire globe. and signs of diseases of various descriptions, some of
which might have been caused by parasites. Persons with
Archaeological Evidence raging fevers, which might have been difficult to control
of Parasitic Infections without the medical technology enjoyed today, were
found in various works, including those of the celebrated
The past history going back for centuries, and bolstered Hippocrates, author of the Hippocratic Oath still in use
by archaeological specimens and written records, has in differing versions and whose corporate works are
confirmed that parasitic infections have a history of infect- known as the Corpus Hippocratorum. Other documenta-
ing humans for as long as any sort of record of humans is tion of apparent parasitic maladies are found in ancient
available. Much of this information predates written his- works from physicians as members of civilizations other
tory, with the finding of archaeological specimens that are than Greek and Middle Eastern areas.
more ancient than written records. But several thousand Although the medical literature of the Middle Ages
years BC, work by ancient Egyptian physicians and then is quite scant, there are many references to the malady of
later Greek physicians who wrote of parasitic infections, being infected by parasitic worms. In some cases, they
were recorded. One of the significant areas of the study were considered as the primary cause of certain diseases.
of parasitology today is that of archaeologists who study However, generally the literature of the period was rife
the evolution of humans and who have documented the with those who were somewhat ignorant due to stultifying