CHAPTER 1 – The Nature of Plagues
Peter Turner a World War II veteran attended a American Legion convention in Philadelphia. Two
days later he fell ill with a high fever, chills, headache, and muscle aches and pains. He thought it
was just a cold but a few days later he had dry coughs, chest pain, shortness of breath, vomiting and
diahrea. Within a week his lungs filled with fluid and pus, and he was confused and disoriented with
hallucinations and a loss of memory. 221 of the legionnaires became ill but Turner and 33 others
died of pneumonia. This disease was called legionnaires disease and came to public attention and so
authorities launched an investigation into the cause of this disease. No person to person spread
could be documented but people still thought this could result in an epidemic.
Studies showed that those who had the disease spent a lot more time in the hotel lobby
then others who were healthy had. Air was a probable pathway for the disease to spread,
the theory was that bacteria was aspired in the form of aerosolized water from either the
cooling tower or evaporative condenser. Aspiration is produced by choking, secretions in the
mouth get past the choking reflex and instead of going into the esophagus and stomach it
goes into the lungs. Protective aspects against aspiration are usually just weaker in older
people and smokers along with those with lung disease. These outbreaks of Legionnaires
disease have been traced back to water heaters, whirlpool baths, respiratory therapy
equipment and ultrasonic misters used in grocery stores.
A few days later Mary Benton a TA was doubling over in pain everytime she went to the
bathroom, she thought she had an infection or was suffering from overeating. Soon she had
nausea, chills, diharea , headache and soar throat. A red rash began to span her body and
her blood pressure had decreased. She had conjunctivitis in both eyes and her chest xray
was normal but her pelvic examination revealed a brown discharge. Despite medications her
condition worsened. She died from multiorgan failure/ low blood pressure, hepatitis, renal
insufficiency, and internal bloodclots. Laboratory tests showed that there was some sort of
bacteria in vaginal secretions. This was called the toxic shock syndrome, over the years some
girls seemed to get TSS too. Starts out with high fever and vomiting but later went on to
muscle aches, soar throat, fainting, eyes become bloodshot and many other things occur,
and blood pressure drops and if it remained low for a long enough period, circulatory
collapse produces a shock. TSS is a gender specific disease but it was not an STD, it was
linked to a specific type of tampon that provides a good environment for toxin producing
bacteria. Vaginal temperature and neutral pH were enhanced by the use of this tampon.
SARS began in 2003 with an old Chinese man in Hong Kong who became ill after attending a
wedding. Soon he suffered respiratory failure and died. It spread fast, in less than a month a
10 people were infected. In an age where we think immunizations can cure everything we
don’t really realize how dangerous diseases. Diseases can erupt and spread fast because of
the movement of goods and people. New diseases may be relted to advances in technology
(tampons and airconditioning systems)
Living off others - The germs that caused SARS legionairres disease and TSS are parasites. Parasites
are unable to live on their own and live off the nourishment of other living things, they obtain
resources for their growth and reproduction. Parasitism is a relationship between two organisms in which one benefits at the expense of another and so parasites are harmful to their host. Parasites
come in many different forms. Some are made of a fragment of genetic material wrapped in a
protein such as a virus. Others (bacteria, fungi, protozoa) consist of a single cell and some are made
of many cells (mosquitoes, flies, ticks. . .). Some parasites such as hookworms, tapeworms, the
malaraia parasite and HIV live inside the body, whereas others live on the surface. Parasites vary in
size microparasite (malaria) and macroparasite (hookworm). Malaria sits inside a blood cell that is
1/5000 of an inch in diameter, if 10 percent of your blood was infected then it would take just a
couple days for it to become lethal as it causes an internal hemmorage.
Some bacteria have complex life cycles and may have several hosts. In malaria it was
mosquitoes and humans. In the curse of the Pharoahs it was humans and snails. In tsetses
flies the host was game animals and humans.
Parasites don’t infect the whole population because of resistance, immunity due to genetic
abnormality or the absence of some critical dietary factor.
For parasites to be successful in this world they must disperse their offsprings or infective
stages to reach new hosts. To do this they create lots of offsprings therby increasing odds
and thus it increases its chance for survival. When a mosquitoes feeds on blood it injects a
dozen thousand parasites present in its salivary gland. Each reproduce really fast and in
large numbers spreading it really quickly.
Hookworms live in attached lining of the small intestine which they pierce through to suck
blood. Each femal produces 10,000 a day (36 million in its lifetime).
HIV is spherical and tiny, but has in incredible capacity to reproduce. It invades an important
white blood cell and spread in there
If the host is not bringing in the nourishment they travel between many hosts “island
hopping” . Some of the parasites eggs and spores can live on its own w/o a host, such as the
anthrax spores that are taken in through breathing it. Direct or indirect movement of
parasites from host to host is called transmission and intermediaries are called vectors.
Transmission by vectors can be mechanical or developmental. It can also occur through
contamination of things (SARS).
Bacteria are prokaryote that are living or are prokarayotes. They can be rods, spheres or
spirals. Protozoa are one celled eukaryotes and can exist independently or be parasitic.
Some parasite need a microscope to be seen and others can be seen with the eye. The
ultimate microparasite is a virus, they are very small and can only be seen with an electon
microscope, its DNA has everything except for what is needed for reproduction, it must use
another cells machinery to reproduce, they are not alive but can be killed if the DNA/ RNA is
not present. Microparasites are called germs because they are infectious micrrobes.
Larger macroparasites can be seen with the eye and are made of many cells, they do not
multiply in an infected individual except when there is a larval stage in the intermediary
host. They actually produce infective stages that usually pass out of the body of one host
before transmission to another.
Plagues and Parasites – In antiquity all diseases that broke out were called a plague (to strike a blow
that wounds). TSS and Legionairres disease was not contagious but Influenza and SARS was along
with the common cold. SARS and Influenza were upper respiratory diseases, the flu contagious 24 hours befo