Microorganisms

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Microorganisms Protists, Bacteria and Viruses
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Protists
Protists are eukaryotic Which means they are
cells with a nucleus. They can be unicellular or
multicellular They can be animal-like,
fungus-like or plant-like.
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Some protists
amoeba
amoeba ingesting a paramecium
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Paramecium
paramecium05pc60x.mpeg paramecium08ob.mpeg
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Giardiasis (GEE-are-DYE-uh-sis) is a diarrheal
illness caused by a one-celled, microscopic
parasite, Giardia intestinalis (also known as
Giardia lamblia). Once an animal or person has
been infected with Giardia intestinalis, the
parasite lives in the intestine and is passed in
the stool. The Giardia parasite lives in the
intestine of infected humans or animals. Millions
of germs can be released in a bowel movement from
an infected human or animal. Giardia is found in
soil, food, water, or surfaces that have been
contaminated with the feces from infected humans
or animals. You can become infected after
accidentally swallowing the parasite
Giardia
information on Giardia
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Plasmodium
Malaria is caused by protozoan parasites of the
genus Plasmodium. Malaria is currently endemic in
91 countries with small pockets of transmission
occurring in a further eight countries.
Plasmodium falciparum is the predominant
parasite. More than 120 million clinical cases
and over 1 million deaths occur in the world each
year.
Plasmodium develops in the gut of the mosquito
and is passed on in the saliva of an infected
insect each time it takes a new blood meal. The
parasites are then carried by the blood in the
victim's liver where they invade the cells and
multiply.
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Symptoms may appear and disappear in phases and
may come and go at various time frames. These
cyclic symptoms of malaria are caused by the life
cycle of the parasites - as they develop, mature,
reproduce and are once again released into the
blood stream to infect even more blood and liver
cells. When this happens a high swinging fever
can develop, with marked shivering and intense
perspiration. Further serious complication
involving the kidneys and brain can then develop
leading to delirium and coma.
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Bacteria
Bacteria are prokaryotic cells.This means, they
do NOT contain a nucleus. They have a Cell Wall
and a Cell Membrane. Their genetic material (DNA)
simply floats around in the cytoplasm. Many have
flagella for locomotion.
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The structure of a bacterium
e-class on bacteria
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Spherical Bacteria - Cocci
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Rod-Shaped Bacteria Bacilli(eg. E-coli)
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Spirial Shaped Bacteria - Spirilla
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Helpful Bacteria on/in our bodies
It has been calculated that the normal human
houses about 1012 bacteria on the skin, 1010 in
the mouth, and 1014 in the gastrointestinal
tract. This number is much greater than the
number of our own cells in the human body.
1014 100 000 000 000 000
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Some bacteria are necessary for our survival. For
example in the intestine we have Lactobacillus
acidophilus (the most famous), Lactobacillus
bifidus (more common to the baby colon), and
Streptococcus faecium. Bacteria help extract
water from the feces and produce Vitamin K in our
large intestine
acidophilus
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Harmful (Pathogenic) Bacteria
What is E. coli O157H7? Escherichia coli (E.
coli) is a bacterium that is commonly present in
the intestines of humans and animals.
What makes E. coli O157H7 so dangerous? Most
strains of E. coli are harmless, the exception
being the strain O157H7 that causes severe
diarrhea leading to renal (kidney) damage and
other serious complications including death.
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E. coli O157 H7 also has the ability to cause
disease at a very low dose, survive at low
temperatures and under acidic conditions.
Who is more susceptible to infection from E. coli
O157H7? People of all age groups are susceptible
to these bacteria however immunocompromised,
elderly and young children are at a higher risk.
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What diseases are caused by E. O157H7? Infection
with Escherichia coli O157H7 can range from
being asymptomatic to having mild to severe
gastrointestinal symptoms. These symptoms
manifest as abdominal cramping, bloody or
nonbloody diarrhea. In an uncomplicated case, the
illness should recover in less than 5-10 days.
Complications Hemolytic uremic syndrome (HUS) is
one of the complications following E. coli
O157H7 infection especially in children below
the age of 5. HUS is one of the most common
causes of acute renal failure in children.
Hemolytic uremic syndrome is characterized by
acute renal failure, and a type of anemia and
fever. One-third of the children diagnosed with
HUS do not recover completely and will eventually
need a dialysis.
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The disease causing pathogen can be transmitted
by a) Eating uncooked/ undercooked ground
beefb) Consumption of contaminated sprouts,
lettuce, salami, unpasteurized milk c) Swimming
in or drinking sewage contaminated waterd)
Feco-oral transmission through an infected person
to a healthy individual due to unhygienic
practices.
spinach warning Sept 2006
latest tainted spinach linked to pigs
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In May 2000, seven residents of Walkerton died
after drinking water contaminated with E.coli,
and in April 2001, nearly 6,000 people in North
Battleford became ill after drinking water
contaminated with the Cryptosporidium parvum
protozoan.
In May 2000, bacteria seeped into Walkerton's
town well. The deadly E. coli then slipped
quietly through a maze of pipes and into the
homes of Walkerton, Ont. Unsuspecting residents
thirstily drank the polluted water and bathed in
their bacteria-ridden tubs. But soon after, they
began experiencing common symptoms of infection
bloody diarrhea and throbbing cramps. Seven
people would eventually die and another 1286
would fall ill. The investigation which followed
exposed an alarmingly unstable waterworks system
made fragile by government cuts.
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A few diseases in humans caused by bacteria
cholera, diphtheria, leprosy, plague, pneumonia,
strep throat, tetanus, tuberculosis, and typhoid
fever.
Antibiotics are used to kill harmful bacteria,
but have the side-effect of also killing useful
bacteria. Also, the over-use of antibiotics can
lead to resistant strains of bacteria that are
hard to fight.
The CDC estimates that each year, nearly 2
million people in the United States acquire an
infection while in a hospital, resulting in
90,000 deaths. More than 70 percent of the
bacteria that cause these infections are
resistant to at least one of the antibiotics
commonly used to treat them.
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Some Other Harmful Bacteria
Salmonella enteritidis bacterium
A person infected with the Salmonella enteritidis
bacterium usually has fever, abdominal cramps,
and diarrhea beginning 12 to 72 hours after
consuming a contaminated food or beverage.
The illness usually lasts 4 to 7 days, and most
persons recover without antibiotic treatment.
However, the diarrhea can be severe, and the
person may be ill enough to require
hospitalization. The elderly, infants, and those
with impaired immune systems may have a more
severe illness. In these patients, the infection
may spread from the intestines to the blood
stream, and then to other body sites and can
cause death unless the person is treated promptly
with antibiotics. It can be found in Raw meats,
poultry, eggs, milk and dairy products, fish,
shrimp, frog legs, yeast, coconut, sauces and
salad dressing, cake mixes, cream-filled desserts
and toppings, dried gelatin, peanut butter,
cocoa, and chocolate.
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Botulism
Clostridium botulinum is the name of a group of
bacteria commonly found in soil. These rod-shaped
organisms grow best in low oxygen conditions. The
bacteria form spores which allow them to survive
in a dormant state until exposed to conditions
that can support their growth.
Botulism is a rare but serious paralytic illness
caused by a nerve toxin that is produced by the
bacterium Clostridium botulinum. three main
kinds of botulism Foodborne botulism is caused
by eating foods that contain the botulism toxin.
Wound botulism is caused by toxin produced from
a wound infected with Clostridium botulinum.
Infant botulism is caused by consuming the
spores of the botulinum bacteria, which then grow
in the intestines and release toxin. All forms
of botulism can be fatal and are considered
medical emergencies. Foodborne botulism can be
especially dangerous because many people can be
poisoned by eating a contaminated food.
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The respiratory failure and paralysis that occur
with severe botulism may require a patient to be
on a breathing machine (ventilator) for weeks,
plus intensive medical and nursing care. After
several weeks, the paralysis slowly improves. If
diagnosed early, foodborne and wound botulism can
be treated with an antitoxin which blocks the
action of toxin circulating in the blood. This
can prevent patients from worsening, but recovery
still takes many weeks. Physicians may try to
remove contaminated food still in the gut by
inducing vomiting or by using enemas. Wounds
should be treated, usually surgically, to remove
the source of the toxin-producing bacteria. Good
supportive care in a hospital is the mainstay of
therapy for all forms of botulism. Botulism can
result in death due to respiratory failure.
However, in the past 50 years the proportion of
patients with botulism who die has fallen from
about 50 to 8. A patient with severe botulism
may require a breathing machine as well as
intensive medical and nursing care for several
months. Patients who survive an episode of
botulism poisoning may have fatigue and shortness
of breath for years and long-term therapy may be
needed to aid recovery.
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Foodborne botulism has often been from
home-canned foods with low acid content, such as
asparagus, green beans, beets and corn. However,
outbreaks of botulism from more unusual sources
such as chopped garlic in oil, chile peppers,
tomatoes, improperly handled baked potatoes
wrapped in aluminum foil, and home-canned or
fermented fish. Persons who do home canning
should follow strict hygienic procedures to
reduce contamination of foods. Oils infused with
garlic or herbs should be refrigerated. Potatoes
which have been baked while wrapped in aluminum
foil should be kept hot until served or
refrigerated. Because the botulism toxin is
destroyed by high temperatures, persons who eat
home-canned foods should consider boiling the
food for 10 minutes before eating it to ensure
safety. Wound botulism can be prevented by
promptly seeking medical care for infected wounds
and by not using injectable street drugs.
MORE
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Anthrax
Bacillus anthracis(Anthrax bacillus)
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Anthrax is an acute infectious disease caused by
the spore-forming bacterium Bacillus anthracis.
Anthrax most commonly occurs in wild and domestic
lower vertebrates (cattle, sheep, goats, camels,
antelopes, and other herbivores), but it can also
occur in humans when they are exposed to infected
animals or tissue from infected animals. Anthrax
is most common in agricultural regions where it
occurs in animals. These include South and
Central America, Southern and Eastern Europe,
Asia, Africa, the Caribbean, and the Middle East.
When anthrax affects humans, it is usually due to
an occupational exposure to infected animals or
their products. Workers who are exposed to dead
animals and animal products from other countries
where anthrax is more common may become infected.
Humans can become infected with anthrax by
handling products from infected animals or by
inhaling anthrax spores from contaminated animal
products. Anthrax can also be spread by eating
undercooked meat from infected animals. It is
rare to find infected animals in the United
States or Canada. Most (about 95) anthrax
infections occur when the bacterium enters a cut
or abrasion on the skin, such as when handling
contaminated wool, hides, leather or hair
products (especially goat hair) of infected
animals. Inhalation anthrax is usually fatal.
MORE
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In the early 1330s an outbreak of deadly bubonic
plague occurred in China. The bubonic plague
mainly affects rodents, but fleas can transmit
the disease to people. Once people are infected,
they infect others very rapidly. Plague causes
fever and a painful swelling of the lymph glands
called buboes, which is how it gets its name. The
disease also causes spots on the skin that are
red at first and then turn black. Since China
was one of the busiest of the world's trading
nations, it was only a matter of time before the
outbreak of plague in China spread to western
Asia and Europe. In October of 1347, several
Italian merchant ships returned from a trip to
the Black Sea, one of the key links in trade with
China. When the ships docked in Sicily, many of
those on board were already dying of plague.
Within days the disease spread to the city and
the surrounding countryside. An eyewitness tells
what happened "Realizing what a deadly
disaster had come to them, the people quickly
drove the Italians from their city. But the
disease remained, and soon death was everywhere.
Fathers abandoned their sick sons. Lawyers
refused to come and make out wills for the dying.
Friars and nuns were left to care for the sick,
and monasteries and convents were soon deserted,
as they were stricken, too. Bodies were left in
empty houses, and there was no one to give them a
burial."
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The disease struck and killed people with
terrible speed. The Italian writer Boccaccio said
its victims often "ate lunch with their friends
and dinner with their ancestors in paradise." By
the following August, the plague had spread as
far north as England, where people called it "The
Black Death" because of the black spots it
produced on the skin. A terrible killer was loose
across Europe, and Medieval medicine had nothing
to combat it. In winter the disease seemed to
disappear, but only because fleas--which were now
helping to carry it from person to person--are
dormant then. Each spring, the plague attacked
again, killing new victims. After five years 25
million people were dead--one-third of Europe's
people.
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Gene Splicing or Recombinant DNA
Bacteria can contain Plasmids, which are circular
pieces of DNA. (Bacteria dont have nuclei.)
Pieces of DNA with desired characteristics can be
obtained. (eg. DNA which directs the production
of human insulin or frost resistance in plants
etc. etc.)
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A plasmid is cut using an enzyme. Desired DNA
is inserted into the plasmid. It is glued back
together. The plasmid is inserted into a host
bacteria. The host bacteria reproduce and the
offspring contain the inserted DNA (eg. to make
human insulin etc.)
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• Some of the areas where Recombinant DNA will have
  an impact.
• Better Crops (drought heat resistance)
• Recombinant Vaccines (ie. Hepatitis B)
• Prevention and cure of sickle cell anemia
• Prevention and cure of cystic fibrosis
• Production of clotting factors
• Production of insulin
• Production of recombinant pharmaceuticals
• Plants that produce their own insecticides
• Germ line and somatic gene therapy

Proteins that HAVE BEEN manufactured using genes
from bacteria
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Viruses
Viruses are not living organisms. Without a host
cell, viruses cannot carry out their
life-sustaining functions or reproduce. They
cannot synthesize proteins, because they lack
ribosomes. They must use the ribosomes of their
host cells. Viruses cannot generate or store
energy because they lack mitochondria. They have
to derive their energy from the host cell. They
also parasitize the cell for basic building
materials, such as amino acids, nucleotides, and
lipids (fats).
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Viruses have a protein coat with RNA or DNA on
the inside. No other organelles.
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T4 Bacteriophage Infecting a Bacterium
animation of virus infecting bacteria
flash animation of virus infecting
bacteria-choose GIF animation summary below
Sometimes during the process of viral
replication, mutations occur. If the mutation is
harmful, the new virus particle might no longer
be functional (infectious). However, because a
given virus can generate many,. many copies of
itself, even if 200,000 particles are no good,
100 might still be just fine. Further, some
mutations don't lead to harm to the virus, but
instead lead to a functional but now brand-new
strain of virus (Influenza virus can do this
consequently, there are several different strains
of this virus which have to be identified each
year in order to make a vaccine against the
particular strain which might cause the "flu").
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1 Adsorption
2 Penetration
3 Early Replication
4 Late Replication
5 Maturation
6 Release
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The tumor viruses change cells by integrating
their genetic material with the host cell's DNA.
This is a permanent insertion in that the genetic
material is never "removed." Several viruses
have been linked to certain types of cancer The
Epstein-Barr Virus has been linked with Burkitt's
lymphoma. The Hepatitis B and C viruses have
been linked with liver cancer in people with
chronic infections. HTLV-1, a retrovirus, has
been linked to T-cell leukemia. Papilloma
viruses have been linked with cervical cancer.
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Some viruses include
Common cold Arenaviruses Cytomegalovirus Ocular Herpes
Flu Bunyavirus Infant Cytomegalic virus Meningitis
Measles Filovirus Progressive Multifocal Leukoencephalopathy Encephalitis
Rubella Flavivirus Viral gastroenteritis Shingles
Chicken pox Hantavirus Acute Appendicitis Pneumonia
Mumps Rotavirus Hepatitis A Encephalitis,
Polio Viral meningitis Hepatitis B St. Louis encephalitis
Rabies West Nile fever Chronic Hepatitis B Rift Valley Fever
Mononucleosis Arbovirus Hepatitis C Hand, Foot, Mouth Disease
Ebola Parainfluenza Chronic Hepatitis C Hendra Virus
Chickenpox Hepatitis D Enteroviruses
Dengue fever Smallpox Hepatitis E Astrovirus
Yellow fever Epstein-Barr virus Hepatitis X SARS
Lassa fever Dengue hemorrhagic fever Cold sores Japanese encephalitis
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The Polio Virus
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Polio, or more properly poliomyelitis, was one of
the most feared and studied diseases of the first
half of the 20th Century. It appeared
unpredictably, striking its victims, mostly
children, with a frightening randomness that
resulted in near panic during the epidemics of
the 1940s and 50s. Then, in 1955, a breakthrough
occurred when, after massive field trials
involving nearly two-million children, the Salk
vaccine was shown to be effective in preventing
the disease. Today, polio is all-but-forgotten as
it has completely disappeared from developed
countries, and worldwide eradication is predicted
by 2005. However, polio's legacy remains. It is
estimated  that there are 600,000 polio survivors
living in the United States, and the number
worldwide must be in the tens of millions.
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Polio is a highly infectious disease caused by a
virus poliovirus. It invades the nervous system
and can cause total paralysis in a matter of
hours. It can strike at any age, but affects
mainly children under three. Polio is mainly
passed through person-to-person (i.e.,
fecal-oral) contact, and infects persons who do
not have immunity against the disease. There is
no cure for polio, but the disease can be
prevented by immunization with polio vaccine.
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An Influenza (flu) virus. There are billions of
different flu viruses.
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Hepatitus A viruses
Hepatitus B virus
Hepatitus C viruses
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Hepatitis A Hepatitis B Hepatitis C
How Its Spread eating or drinking contaminated food or water. The hepatitis virus is found in faeces. It can be passed on if even a tiny amount of faeces from a person with hepatitis A comes into contact with another person's mouth Unprotected sex Contaminated needles Non-sterilized equipment for tattooing, acupuncture of body piercing, From infected mother to baby, Blood transfusions Unprotected sex Contaminated needles Non-sterilized equipment for tattooing, acupuncture of body piercing, From infected mother to baby, Blood transfusions sharing notes used to snort cocaine
Symptoms a short, mild, flu-like illness nausea and vomiting diarrhoea loss of appetite weight loss jaundice (yellow skin and whites of eyes, darker yellow urine and pale faeces) itchy skin. Some people may need to be admitted to hospital. a short, mild, flu-like illness nausea and vomiting diarrhoea loss of appetite weight loss jaundice (yellow skin and whites of eyes, darker yellow urine and pale faeces) itchy skin. a short, mild, flu-like illness nausea and vomiting diarrhoea loss of appetite weight loss jaundice (yellow skin and whites of eyes, darker yellow urine and pale faeces) itchy skin.
Diagnosis and Treatment Infection with hepatitis A is usually mild, but occasionally causes severe inflammation of the liver, requiring admission to hospital. Most adults fully recover. If they continue to be infected chronic hepatitis liver cirrhosis liver cancer. about 80 will remain infected and can pass on the virus to others. chronic hepatitis liver cirrhosis liver cancer.


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images of many viruses
HIV viruses
Human immunodeficiency virus or HIV is a
retrovirus that causes Acquired Immunodeficiency
Syndrome (AIDS), a condition in which the immune
system begins to fail, leading to
life-threatening opportunistic infections. Spread
by unprotected sex and sharing needles.
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Mononucleosis
The Epstein-Barr virus (EBV), also called Human
herpesvirus 4 , is a virus of the herpes family
(which includes Herpes simplex virus and
Cytomegalovirus), and is one of the most common
viruses in humans. Most people become infected
with EBV, which is often asymptomatic but
commonly causes infectious mononucleosis. It is
named after Michael Epstein and Yvonne Barr, who
together with Bert Achong discovered the virus in
1964
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• Some signs of mononucleosis
• constant fatigue
• fever
• sore throat
• loss of appetite
• swollen lymph nodes (also commonly known as
  glands, located in your neck, underarms, and
  groin)
• headaches
• sore muscles
• larger-than-normal liver and spleen
• skin rash
• abdominal pain

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Avian (Bird) Flu
These influenza viruses occur naturally among
birds. Wild birds worldwide carry the viruses in
their intestines, but usually do not get sick
from them. However, avian influenza is very
contagious among birds and can make some
domesticated birds, including chickens, ducks,
and turkeys, very sick and kill them. The risk
from avian influenza is generally low to most
people, because the viruses do not usually infect
humans. However, confirmed cases of human
infection from several subtypes of avian
influenza infection have been reported since
1997. Most cases of avian influenza infection in
humans have resulted from contact with infected
poultry (e.g., domesticated chicken, ducks, and
turkeys) or surfaces contaminated with
secretion/excretions from infected
birds. Influenza A (H5N1) virus also called
H5N1 virus is an influenza A virus subtype
that occurs mainly in birds, is highly contagious
among birds, and can be deadly to them. H5N1
virus does not usually infect people, but
infections with these viruses have occurred in
humans. Of the few avian influenza viruses that
have crossed the species barrier to infect
humans, H5N1 has caused the largest number of
detected cases of severe disease and death in
humans. However, it is possible that those cases
in the most severely ill people are more likely
to be diagnosed and reported, while milder cases
go unreported.
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West Nile Virus
West Nile virus (WNV) is a potentially serious
illness. Experts believe WNV is established as a
seasonal epidemic in North America that flares up
in the summer and continues into the fall.About
one in 150 people infected with WNV will develop
severe illness. The severe symptoms can include
high fever, headache, neck stiffness, stupor,
disorientation, coma, tremors, convulsions,
muscle weakness, vision loss, numbness and
paralysis. These symptoms may last several weeks,
and neurological effects may be permanent.Milder
Symptoms in Some People. Up to 20 percent of the
people who become infected have symptoms such as
fever, headache, and body aches, nausea,
vomiting, and sometimes swollen lymph glands or a
skin rash on the chest, stomach and back.
Symptoms can last for as short as a few days,
though even healthy people have become sick for
several weeks.No Symptoms in Most People.
Approximately 80 percent of people (about 4 out
of 5) who are infected with WNV will not show any
symptoms at all. Most often, WNV is spread by
the bite of an infected mosquito. Mosquitoes
become infected when they feed on infected birds.
Infected mosquitoes can then spread WNV to humans
and other animals when they bite. Has not been
reported in BC yet, but has in Alberta and other
provinces.
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Human Papiloma Virus
Genital HPV infection is a sexually transmitted
disease (STD) that is caused by human
papillomavirus (HPV). Human papillomavirus is the
name of a group of viruses that includes more
than 100 different strains or types. Approximately
20 million people are currently infected with
HPV. At least 50 percent of sexually active men
and women acquire genital HPV infection at some
point in their lives. By age 50, at least 80
percent of women will have acquired genital HPV
infection The types of HPV that infect the
genital area are spread primarily through genital
contact. Most HPV infections have no signs or
symptoms therefore, most infected persons are
unaware they are infected, yet they can transmit
the virus to a sex partner Most women are
diagnosed with HPV on the basis of abnormal Pap
tests. A Pap test is the primary cancer-screening
tool for cervical cancer or pre-cancerous changes
in the cervix, many of which are related to
HPV. A Pap test can detect pre-cancerous and
cancerous cells on the cervix. Regular Pap
testing and careful medical follow-up, with
treatment if necessary, can help ensure that
pre-cancerous changes in the cervix caused by HPV
infection do not develop into life threatening
cervical cancer.