Transcript Nasty Things that want to harm us

Viruses
 A virus is a sub-
microscopic infectious
agent only capable of
reproducing within a
host cell.
 Virus is Latin for toxin or
poison.
Viruses
 Viruses infect all types of
organisms.
 They are transmitted by
every type of vector.
 They are basically a
nucleic acid covered in a
protein shell (capsid).
 Can cause minor illness
up to a deadly disease.
Influenza Viruses
 Contain all types of flu
viruses from “seasonal flu”
to Avian Flu to Spanish Flu
(a.k.a. H1N1).
 Most influenza viruses
affect humans only, but
some can crossover
species.
 Common transmission is
airborne or waterborne.
 Annoying, but usually not
deadly (H1N1 may be an
exception).
Varicella zoster
 This virus causes chicken
pox.
 Causes skin rash and
lesions.
 Common transmission is
airborne or contact.
 Annoying, but usually
not deadly although
affected adults get it
worse than children.
Herpes simplex virus
 Two strains of this virus
affect humans.
 One causes cold sores and
the other causes watery
blisters on the mucous
membranes of the genitals.
 Transmission is close
contact.
 Not deadly, more than
annoying though as the
virus remains in the cells
for life and reoccurrences
are frequent.
Norovirus
 Formerly Norwalk Virus.
 Causes fun things like
nausea, vomiting, diarrhea,
mild fever…
 Common transmission is
fecal-oral, which basically
means someone did not wash
their hands after a bathroom
break and then handled your
food. Also can be
waterborne.
 Very harsh, but only lasts 1-2
days… not deadly unless you
are really old or really young.
Bacteria
 Bacteria are unicellular
micro-organisms ranging
in length from a few
micrometers to half a
millimeter.
 They come in a variety of
different shapes (cocci,
bacilli and spirilli).
 Bacteria can be found in
almost every ecosystem on
Earth.
 There are an estimated
5 x 1030 bacteria on Earth!
Bacteria Introduction
 Bacteria are found all
over the human body,
however the majority are
harmless or even
beneficial.
 Some bacteria are
pathogenic and cause
disease.
Streptococcus pyogenes
 Chain of round bacteria.
 Causes strep throat.
 Can lead to the “flesh
eating disease” in some
cases!
 Common transmission is
airborne or contact.
 Annoying… flesh eating
disease can be deadly.
Staphylococcus aureus
 Grape like clusters of bacteria
that produce a toxin which can
cause minor skin infections like
pimples or deadly infections like
pneumonia, meningitis, toxicshock syndrome and sepsis.
 Methicillin-Resistant S. aureus
(MRSA) is more common now
in hospitals and is hard to kill,
therefore more patients
succumb to infection.
 Common transmission is
contact.
 Annoying right up to deadly.
E. Coli 0157-H7
 A pathogenic strain of a
usually harmless bacteria.
 Causes severe
gastrointestinal problems
like bloody stool, cramps
and in severe cases, kidney
failure.
 Common transmission is
waterborne or eating
undercooked ground beef.
 Severe, but usually brief,
however there always is a
chance of death.
Acinetobacter baumannii
 Called “Iraqibacter” as it
has hit troops in the
Middle East hard.
 Causes sepsis and in some
cases pneumonia.
 Common transmission is
contact with open wounds.
 Sepsis will kill 3 out of 4
sufferers! A good
bacterium to avoid at all
costs.
Fungi
 Look similar to a plant by
also have much in
common with animals
 Feed by releasing
digestive enzymes into
the surrounding
environment and absorb
the digested nutrients
into their cells
 Some pathogen species.
Ringworm
 Feeds on the protein
keratin found in skin,
hair and nails.
 Loves warm, moist skin.
 Causes an itchy “ring” to
develop on the skin.
 Common transmission is
contact.
 Annoying, but not
deadly.
Tinea pedis
 Athlete's foot fungus..
 Causes skin to be scaly
and flake off. Affects the
feet but can be passed on
to other areas of the
body.
 Common transmission is
contact.
 Can be painful if left
untreated, but not
deadly.
Candida species
 A group of yeast.
 Causes yeast infections
(thrush). Itchy, burning
sensation.
 Common transmission is
contact.
 Can be severe if left
untreated, but rarely
deadly.
Aspergillus species
 Big group of about 200
molds.
 Found in some nuts and
can be carcinogenic!
 Causes allergies, sinus
and lung infections.
 Common transmission is
airborne or contact.
 Mild to severe
discomfort.
Protists
 Microscopic organisms that
have a nucleus.
 Most do not bother us.
 A few are pathogenic.
Protist Examples
Trypanosoma species
 Move by a spiral motion.
 Causes African sleeping
sickness of Chagras’ disease.
Both affects the nervous
system.
 Common transmission is
through an insect vector
(Tsetse fly or mosquito).
 Can be fatal if not treated.
Plasmodium species
 Move by a spiral motion.
 Causes malaria which is a red
blood cell disease.
 Complex life cycle in a human
and mosquito.
 Common transmission is
through an insect vector
(Anopheles mosquito)
 Can be fatal if not treated.
Giardia lamblia
 Causes “Beaver Fever”
 It attaches to the small
intestine’s lumen (inside) and
absorbs nutrients from food the
host digests.
 Common to humans, beavers,
dogs, cats, birds, deer and
sheep.
 Common transmission is
waterborne although fecal-oral
is another route.
 Severe sickness and lethargy,
but not usually deadly if
treated.
Prions
 These are misfolded proteins
that force other proteins in
the host to misfold.
 These misfolded proteins
tend to build up in the central
nervous system and cause
nasty things like Mad Cow
Disease and CreutzfeldtJakob Disease… both lead to
dementia and death.