Our youngsters have never had a
better time for being entertained by movies which
fictitiously generates futuristic dystopian worlds
of vampires and zombies, or mass-extinction through
air-born viruses. Often the vampires and zombies are
created due to an infection. I thought it might be
interesting to consider some of the real invaders of
micro-organic forms, and the way they may invade our
bodies in exotic ways.
Most people are aware of Malaria, and the vector
(carrying, spreading-agent) for that being the mosquito.
But what about so many others?
Go Mad On
Tonsil biopsy in variant CJD. Prion protein
immunostaining. Author: Sbrandner.
Used here under the
Wiki Creative Commons Licence
Spongiform change in brain in CJD
CJD: in its classical form will see
you go mad then die in an average time of 4 to 5
months. In it's variant form, 13 - 15 months.
It's always fatal and there's no cure.
At times called a human form of mad cow disease
(bovine spongiform encephalopathy or BSE) even
though classic CJD is not related to BSE, this
is something you certainly don't want to get.
BSE is believed to be the cause of variant
Creutzfeldt–Jakob (vCJD) disease in humans,
therefore the two terms are often confused.
CJD is caused by an infectious agent
called prions. Prions are misfolded proteins
which replicate by converting their properly
folded counterparts, in their host, to the same
misfolded structure they possess. The disease
leads to rapid neurodegeneration, causing the
brain tissue to develop holes and take a more
sponge-like texture. (see left).
Most people are only aware of CJD due to the
media-scare over one form which causes 'mad cow
disease' BSE - (bovine spongiform
encephalopathy), and a public awareness that
affected beef may have entered the food chain.
However, classic CJD is not directly
related to BSE.
Prions appear to exist in soil where infected
sheep have grazed. They are not living
micro-organisms per se. But they have come from
animals suffering the prion disorder
Most cases of
prion disease are sporadic; that is, they
arise spontaneously for no known reason.
Sometimes, although rare, a prion disease is
inherited due to a faulty gene. Because the
infecting agent is a malformed protein capable
of influencing healthy protein in adjacent
cells, it can also be acquired by
medical procedures, transfusions, or
contaminated food. The sporadic occurring form
of the disease affect populations
worldwide. The incidence of sporadic CJD is
around 1 per million of the population per
annum; males and females are equally affected.
The incidence of the various acquired prion
diseases, however, is more localised to
specific groups and populations.
The CJD form associated with humans affected
by BSE related vectors, is through
contaminated meat. But CJD can also occur in
humans through contamination of surgical
instruments. The existing sterilisation of
surgical instruments will not destroy the
prions. Food containing prions (malformed
proteins) cannot be made safe by cooking. The
protein does not break down at cooking
get CJD by contact with another human being?
get CJD if I cook all my meat properly?
Yes. Because CJD is not
just caused by contaminated food (meat), and if
you eat infected meat, cooking does not destroy
the malformed protein - prions which cause the
Difficult to diagnose because a biopsy involves
invasive procedure into the brain and and sample
taken might be from an uninfected area. There
are no cures or remedies, just preventive health
measures to minimise cross-contamination.
The protein that prions are made of (PrP) is
found throughout the body, even in healthy
people and animals. However, PrP found in
infectious material has a different structure
and is resistant to proteases, the enzymes in
the body that can normally break down proteins.
The normal form of the protein is called PrPC,
while the infectious form is called PrPSc
- the ''C'' refers to 'cellular' or 'common'
PrP, while the ''Sc'' refers to 'scrapie', a
prion disease occurring in sheep. While PrPC
is structurally well-defined, PrPSc
is certainly polydisperse and defined at a
relatively poor level. PrP can be induced to
fold into other more-or-less well-defined
isoforms in vitro, and their relationship to the
form that are pathogenic in vivo is not
Prions do not themselves behave
like living components. They are not alive. They
consist of a protein form which is structurally
folded, which is not how our proteins should be.
The prions seem able to influence similar protein
in their hosts. They make normal versions of the
protein restructure and fold... effectively ending
their function in nerve tissue and cells.
And that means brain
cells and nerve tissue no longer are healthy.
will make you run
Author CDC / Janice Carr
Wiki creative commons licence
3D model of
by mol smith
about Giardia Here
And if those first few don't scare you enough to
run to the toilet, this one will take you there. Giardia is a flagellated protozoan
parasite. If lives inside the intestines of
animals, infected with it and can be passed to
humans. Individuals become infected
through ingesting or coming into contact with
contaminated food, soil, or water, mainly
through the presence of waste products from
Normally, after a day or two, people infected
with this protozoan will get abdominal cramps,
violent diarrhea, and will begin vomiting. The
infection is untreated can last for 2 to 6
weeks, and in a few individuals - much
longer. Medication containing tinidazole
or metronidazole is used to treat the infection
and reduce its severity and time suffering.
die by being infected?
Most people recover naturally.
Although infection can last for
several months to years with
continuing symptoms in some people
if not treated. Children with
chronic infection may fail to thrive
will make you breathless - Pneumonia
Photo Credit: CDC/Janice Carr
Content Providers(s): CDC/Dr. Richard Facklam
Public Domain via wiki commons licence
The bacterium Streptococcus pneumoniae,
a common cause of pneumonia. The disease/infection has
been known to humankind since early Greek times,
over 2000 years ago. The symptoms were described by
Hippocrates (c. 460 BC – 370 BC)
It was not until the 1800s when Edwin
Klebs became the first to observe bacteria in the airways
of persons having died of pneumonia in 1875. Initial work
identified the two common bacterial causes, Streptococcus
pneumoniae and Klebsiella pneumoniae, and was performed by
Carl Friedländer and Albert Fränkell in 1882 and 1884,
Pneumonia is not just an infection, it is more
known as a condition of the lungs which may be caused by
a variety of factors including non-infectious damage
through smoking or inhaling toxic dust.
CAP or Community-Acquired Pneumonia
is caused by an infecting vector which may be bacteria,
a virus, air borne fungi, or parasites such as
Toxoplasma gondii, Strongyloides stercoralis, Ascaris
lumbricoides, and Plasmodium malariae.
Half of all cases due to bacteria
are caused by Streptococcus pneumoniae. Other commonly
isolated bacteria include: Haemophilus influenzae,
Chlamydophila pneumoniae, and Mycoplasma pneumoniae.
Poor country populations have high
incidents of Pneumonia with high death rates in
children. Anti-biotic's can help fight bacteria-caused
pneumonia but people with existing lung damage and
elderly people remain under greater risk of fatal
outcomes. Fungal pneumonia is uncommon, but occurs more
commonly in individuals with weakened immune systems due
to AIDS, immunosuppressive drugs, or other medical
problems. Fungi causing pneumonia are Histoplasma
capsulatum, blastomyces, Cryptococcus neoformans,
Pneumocystis jiroveci, and Coccidioides immitis.
X-ray of Lung affected by
Pneumonia. Note the white (denser) wedge in the right
lung, not apparent in the other lung.
A very prominent pneumonia of the middle lobe of the right
lung. Author James Heilman, MD. Used here under the Wiki
Creative Commons licence.
CT of the chest demonstrating right-sided pneumonia ( left
side of the image ) by James Heilman, MD
Creative Commons licence.