CLINICAL LAB SCIENEC

114
ESSENTIALS OF CLINICAL LABORATORY SCIENCE
provided to the medial laboratory worker, along with all those in other medical
professions with possible contact with blood and body fluids. HIV causes a disease
called AIDS (acquired immunodeficiency syndrome). A syndrome is a group
or collection of symptoms and signs associated with a particular disease. The
original source of the virus is in disagreement among many medical specialists.
Two theories have been proposed as to its origin. Some postulate that the organism
originated with the hunting and eating of the green monkey of Africa, and
others believe that the disease originated with the administration of polio vaccine
made from the kidneys of rhesus monkeys. Neither theory has been proved
to date. Manifestations and symptoms of the disease and are well documented
and predictable. With proper precautions, the health care worker is at no more
risk of contracting HIV than the average layperson.
Several strains of HIV (the AIDS virus) exist, and some are similar to those
found in animals. For instance, feline leukemia is thought to be caused by a strain
of virus that is almost identical to that of HIV; to date, humans are considered
naturally immune to this strain of the virus. In addition, other significant bloodborne
viruses pose threats to human life and to blood supplies. In some parts
of the world, epidemics of both human T-lymphotropic virus 1 and 2 (HTLV-1
and HTLV-2) have occurred. This poses such a risk to the blood supplies of the
United States that testing of each unit of blood for HTLV-1 and HTLV-2 is performed.
Such was the case in the 1991 Persian Gulf conflict, during which massive
quantities of blood were collected and tested for the presence of these two
bloodborne viruses. Symptoms associated with AIDS are caused by the presence
of a virus that commonly attacks the immune system, leaving the victim susceptible
to a number of opportunistic infections. Symptoms will depend on the site
of infection and the organism involved. Initial symptoms may be insidious or
mild, with nonspecific symptoms such as those associated with a flu-like illness.
Signs and symptoms may include lymphadenopathy (enlargement or tenderness
of the lymph nodes), anorexia , chronic diarrhea, weight loss, fever , and fatigue .
Later stage symptoms include Kaposi’s sarcoma , manifested by red-brown to
purple lesions of the skin and mucous membranes.
AIDS has been found worldwide. It was first identified in the United States
in 1981, but may have been present for some years before sufficient occurrences,
diagnostic technology, and documentation existed to investigate it as an important
malady. Some reports indicate that tests performed on the blood serum
saved from an adolescent who died with an undiagnosed and wasting disease in
the late 1960s indicate that there may have been antibodies developed against
HIV at that time. The disease is now raging in a number of areas of the world,
and efforts to eradicate it have not been effective to date, often because of political
views by heads of states in some developing countries.
Humans are now recognized as reservoirs of HIV . A reservoir may be an
environmental habitat such as water or soil, or a living organism such as humans.
The transmission or passing of the AIDS virus from one person to another has
been found to occur chiefly with blood, semen, saliva , tissue fluids, and vaginal
fluids. Urine , tears, perspiration, vomitus, and feces may also contain the virus
(Table 6-1). However, to date, there have been no documented cases of transmission
from contact with fluids other than blood, semen, and vaginal secretions. In
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