Transcript We are Not Alone

We are Not Alone
They are in the air
we breathe . . .
In our food .
. .
On our skin .
. .
-on everything
we touch.
They are .
. .
microorganisms
What are
microorganisms?
(also called microbes)
Microbes are small living plants or
animals most of which are not visible to
the naked eye.
Some microbes cause disease or infection.
Many microbes are “good” organisms that
help keep balance in the environment
and the body.
What microbes lack in size,
they make up in number.
On the average human, there are
about 100 trillion microbes.
Good vs. Bad
Microorganisms:
Microorganisms that cause disease
(germs) are referred to as pathogens.
Yeah,
I’m bad.
Microorganisms that are
harmless or beneficial are
called nonpathogens.
Most microbes are considered
beneficial or harmless.
87%
beneficial organisms
10%
Pathogens 3%
opportunists
The role of good
microorganisms
Marine & freshwater microbes form
the basis of the food chain in oceans,
lakes, and rivers.
Soil microbes help
break down wastes.
Humans and other
animals depend on
bacteria in their
intestines for digestion
and synthesis of
vitamins including:
vitamin B (for metabolism)
vitamin K (for blood clotting)
Microorganisms have many
commercial applications
They are used in synthesis of chemical
products such as:
acetone
organic
acids
alcohol
enzymes
many
drugs
They are used in the
food industry for producing:
pickles
vinegar
cheese
alcoholic beverages
green olives
bread
yogurt
Main Classes of Pathogenic
Organisms:
1) Bacteria
• simple one-celled organisms
• At home within “climate” of human body
• compose largest group of pathogens
2)Fungi: yeasts & molds
• Plant-like organisms that live on dead
organic matter
• Grow best in dark, damp places
3) Viruses - smallest microbes
•acellular particles (not a complete cell)
4) Protozoa
•one-celled animals often found in decayed
materials & contaminated water
5) Helminths
•parasitic worms
•caused by larval & egg infestations
Bacterial Infections
Tuberculosis
• Tuberculosis (TB) is a potentially serious
infectious disease that mainly affects your
lungs. The bacteria that cause tuberculosis
are spread from one person to another
through tiny droplets released into the air
via coughs and sneezes.
Medications are the cornerstone of tuberculosis treatment. But treating TB takes much longer than treating
other types of bacterial infections. With tuberculosis, you must take antibiotics for at least six to nine
months. The exact drugs and length of treatment depend on your age, overall health, possible drug
resistance, the form of TB (latent or active) and the infection's location in the body.
Clostridium Difficile
aka C-Diff
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a bacterium that can cause symptoms ranging from diarrhea to life-threatening
inflammation of the colon.
C. difficile bacteria are passed in feces and spread to food, surfaces and objects when
people who are infected don't wash their hands thoroughly. The bacteria produce spores
that can persist in a room for weeks or months. If you touch a surface contaminated with
C. difficile, you may then unknowingly swallow the bacteria.
Your intestines contain millions of bacteria, many of which help protect your body from
infection. But when you take an antibiotic to treat an infection, the drug can destroy
some of the normal, helpful bacteria as well as the bacteria causing the illness. Without
enough healthy bacteria, C. difficile can quickly grow out of control.
Once established, C. difficile can produce toxins that attack the lining of the intestine.
The toxins destroy cells and produce patches (plaques) of inflammatory cells and
decaying cellular debris inside the colon and cause watery diarrhea.
Treatment
Doctors typically prescribe a 10-day course of one of the following oral antibiotics:
metronidazole (Flagyl), Dificid (fidaxomicin), or vancomycin (Vancocin). Flagyl is
usually tried first. Improvement usually happens within 72 hours after starting
antibiotics, but the diarrhea may return temporarily. Another round of antibiotics
is needed in about 25% of cases.
In addition to prescribed medications, treatment may include:
Probiotics. Available in most drug and health food stores without a prescription,
probiotics are "good" bacteria that colonize in the gut and may help keep C. diff.
infection from recurring if taken along with prescribed medicines.
Fluids. Drinking plenty of water and other fluids or getting intravenous fluids can
help guard against dehydration from diarrhea.
For severe cases they are now using fecal transplants.
Necrotizing Fasciitis
Impetigo
highly contagious bacterial infection
• Impetigo is a fairly common superficial skin
infection caused by bacteria. It may occur
on normal skin, but the bacteria usually
invades at the site of a skin abrasion,
scratch, or insect bite.
• Treatment is with antibiotics.
Extensive case of impetigo
on underarm of baby.
Fetal Tetanus
(note severe muscle contractions)
Due to toxin production as a result of bacterial
infection.
• Tetanus, also known as lockjaw, is caused
by bacterial spores that have entered a deep
wound. The spores germinate and produce
a toxin which interferes with nerves
controlling muscles. Progressive muscular
spasms result.
• If muscle spasms develop early and are
severe, chances of recovery are poor.
• Prevention through immunization is the best
treatment
Diphtheria
Note swelling in neck
• Diphtheria is an acute bacterial infection
that usually attacks the respiratory tract.
The infection occurs by inhalation of
airborne droplets.
Diphtheria membrane
Cellulitis
An acute bacterial
inflammation of
connective tissue.
• Cellulitis usually occurs with dermatitis, a
fungal infection, or after a skin injury. It
may be accompanied by a fever.
• Treatment: antibiotics; elevation of infected
area; application of hot, moist compresses
to site.
Lymes Disease
hallmark “bulls-eye” lesion
• Lyme disease was first diagnosed in New Lyme,
Connecticut as a rare form of arthritis. It is, however, now
known to be a bacterial infection caused by a spirochete
that is present in the deer tick. The vector (insect that
carries the infection) usually transfers the bacteria by
biting a host (human).
• Signs and symptoms usually include: papule that becomes
red, warm, and itchy. The lesion may grow to over 20
inches in diameter; it typically resembles a bull’s eye or
target. Malaise and fatigue are constant. There are
generally intermittent episodes of headaches, neck
stillness, fever, chills, & achiness.
• Treatment is a 10 to 20-day course of antibiotics.
Tiny deer tick vector that transmits
lymes disease.
Due to its small size, the deer tick is often hard to see, making
detecting of this vector difficult.
Fungal Infections
Candidiasis: Oral Thrush
• Candida is part of the normal flora of the
mouth. It is an opportunistic infection that
is usually held in check by other organisms
and the immune system. When the immune
system is compromised (chemotherapy,
long-term illness, transplantation, stress,
AIDS, etc.), the infection can occur.
• Signs: cream-colored patches on tongue,
mouth, and/or throat.
• Treatment is with oral antifungal mouth
solution --Nystatin. (“Swish & Swallow)
Oral Thrush:
tongue
Candidiasis of Skin
Typical red, slightly most lesions.
• Candidiasis of the skin is characterized by pruritus
(itching) and peeling. This fungal infection usually
occurs in damp moist areas. It is often seen in
folds of skin. The fungi will spread, producing a
fringed irregular edge and pustules. The
individual is subject to soreness, itching, and
peeling of the lesion. Predisposing factors might
include: diabetes, antibiotic therapy, immune
deficiency, oral contraceptive use, cytotoxic drug
therpay, and obesity.
• Other common manifestations of skin candidiasis
are: diaper rash & vaginitis.
Nail Fungus
• Nail fungi are usually a result of extended
exposure to moisture. (e.g. moisture trapped
under acrylic nails). Nail beds can become
red and swollen. The infected nail is
whitish-yellow and tends to be flaky and
soft. Purulent discharge may be seen from
nail bed.
• Treatment may include topical and or oral
antifungal medication. Sometimes the nail
may be removed.
Black Hairy Tongue
• This fungal infection causes hair-like
papillae on top of tongue to grow. It
produces a condition in which the tongue
looks as though it is covered with hair.
Cutaneous Fungal Infection:
Tinea Versicolor
Note: hypopigmented fungal lesions
• The white patches seen on skin are due to
colonies of fungi which prohibit regular
pigmentation. These patches usually have a
slightly raised, velvety texture.
• Treatment includes use of an antifungal
sulfur soap which is left on skin overnight
for a period of a month. Topical antifungal
ointments may help.
Cutaneous Fungal Infection:
Ringworm
• “Ringworm” is due to a parasite, not an
actual worm. The infestation was named
after the characteristic rings seen on the
skin. These rings can grow outward as the
infection spreads. Ringworm is very
contagious and may spread through entire
households and from schoolmate to
schoolmate. For a mild infection, treatment
is an over-the-counter antifungal agent.
Cutaneous Blastomycosis: Hand & Wrist
• Blastomycosis is caused by a yeast-like
fungus. Cutaneous blastomyucosis causes
nonpruritic lesions on exposed body parts
which may become raised and reddened and
sometimes necrotic.
Subcutaneous
Blastomycosis:
Manifested by
subcutaneous
abscesses in upper
chest
• Cutaneous blastomycosis lesions can
disseminate to bone and cause subcutaneous
soft tissue swelling resulting in tenderness
and warmth over bony lesions.
• Treatment with antifungal medication
amphotericin B or fluconazol may be used.
Chromomycosis
Deep fungal infection
with granulomatous
lesions.
• Chromomycosis is a slowly spreading
fungal infection of the skin and
subcutaneous tissues. It can produce
granulomatous lesions on the legs or arms
and may spread to the brain if not treated.
• This type of fungal infection requires a
systemic antifungal agent. The condition is
chronic.
Viral Infections
Influenza: The Flu
Influenza, or flu, is a respiratory illness that is caused by a
virus. Flu is highly contagious and is usually spread by the
coughs and sneezes of a person who is infected.
Not treated with Antibiotics!!
Tamaflu
Viral Infection: Verruca Vulgaris (Wart)
• Warts are common, benign viral infections
of the skin caused by the human
papillomavirus Some warts disappear
readily with treatment whereas others
necessitate prolonged treatment.
• Treatment might include: electrodesiccation
(effective for common warts), cryotherapy
(useful for facial or genital warts), acid
therapy (not recommended for areas where
perspiration is heavy)
Herpes Type I: Oral Herpes
• Herpes type I affects skin and mucous
membranes. It commonly produces cold
sores and fever blisters. Presently, there is
no cure for herpes virus.
More Oral Herpes
healing stage
Neonatal Herpes
Premature infant born with classic
“cigarette burn” pattern of HSV infection.
• Most cases of herpes simples virus (HSV)
infection occur when infants are
contaminated by the mother’s reproductive
tract immediately prior to or during birth.
HSV infections can be very destructive to
the fetus or newborn and in some cases may
be fatal.
Poliomyelitis
(also called infantile
paralysis)
Note: deformed
right leg
• Poliomyelitis is an acute communicable disease caused by
the poliovirus. Polio can range in severity from inapparent
infection to fatal paralysis. The virus can affect the motor
nerve cells and cause paralysis to various parts of the body.
Only about 10% of infected people develop identifiable
symptoms, and researchers report that paralysis probably
affects fewer than 1% of those infected with the poliovirus.
• Polio was first recognized in 1840 when it became an
epidemic in Norway and Sweden. Outbreaks became
pandemic and the incidence of infection peaked during the
early 1950s. In 1955, Jonas Salk created the polio vaccine
which has effectively eliminated poliomyelitis.
Iron Lung: used by polio victims
The polio virus
could cause
muscular
paralysis to
the diaphragm
and intercostal
muscles. When
this happened,
breathing was
possible only
with the “iron
lungs”.
Varicella (Chickenpox with oral
involvement)
• Varicella is an airborne infection. Symptoms
include lethargy and raised skin eruptions that are
pruritic (itchy). There are three stages of the
eruptions: papules, vesicles, & crusted lesions
when vesicles have opened. Chickenpox is
contagious as long as one has lesions. There is a
varicella vaccination which prevents chickenpox.
• Shingles (herpes zoster) is a condition that can
develop in people who have had chickenpox. The
virus becomes dormant in nerve cells and may
later be stimulated and cause painful skin
eruptions along skin supplied by the infected
nerve.
Measles
(rubeola)
Rash usually begins
on face and spreads
to trunk and
extremities.
• Measles is a very contagious viral infection.
Transmission of rubella is airborne by way
of infected droplets from the nose of mouth.
• Signs and Symptoms include: high fever,
pain of eyes and sensitivity to light. The
most characteristic sign is a maculopapular
rash (red blotch and tiny bump). Persons
are contagious until the rash is gone.
• Vaccination against rubella is effective.
Mumps:
Note edema to cheeks and neck
• Mumps is caused by a virus and spread by
inhalation of infected droplets. Affected
individuals become contagious one day before the
symptoms are apparent.
• Symptoms can include: swollen, painful salivary
glands which cause the cheeks to puff out, lowgrade fever, & lethargy. Mumps is not a serious
disease. It rarely lasts more than two weeks. In
rare instances, encephalitis may develop.
• The mumps vaccine is safe and effective.
Viral Hepatitis
Severely distended
abdomen (ascites).
Secondary complication
from hepatitis.
• Hepatitis may become chronic or severe and
result in cirrhosis of the liver and portal
hypertension. As a result of portal
hypertension, excess fluid seeps from the
liver into the abdominal cavity (ascites).
Treatment for ascites might includes
diuretics, or abdominocentesis.
Parasitic & Protozoan
Infections
Leishmaniasis
(protozoan systemic
disease)
Severe nodular,
disfiguring lesions
transmitted by sand fly
• Leishmaniasis (pronounced lish man-i a-sis)
are transmitted when an infected sandfly
bites and enters the blood of the host.
Leishmaniasis is endemic to most tropical
and subtropical countries.
Dracunculiasis (Fiery Dragon Worm)
Found just under skin of human host.
Causes blisters at site of infestation.
• There is a wide geographical distribution of these
”dragon” worms: Asia, Middle East, Arabia, and
North and equatorial Africa). Humans are
generally infested with this parasite by drinking
contaminated water. Once in the human, worms
migrate from intestinal tract via subcutaneous
tissue to the skin where the fertilized female
worms reach maturity and produce juveniles.
(Male worms die after fertilization.) Sores
produced by reproductive female worms result in
a blister. Oftentimes, these sores can be infected
with bacteria, resulting in abscesses.
Ulceration from worm.
• Eventually a superficial blister will ulcerate
and the worm is visible. At this point, most
infestations are treated by simply removing
female worm. Typically, the worm is
attached to a small stick and removed by
slowly winding the worm on to the stick.
Although this is a primitive treatment, it is
an effective method. It does not prevent
much of the damage caused by worms nor
does this method prevent reinfection.
A fiery dragon worm emerges
from leg.
Elphantiasis
(filariasis)
• The microscopic larvae of the filarial worm
enter the body through the bite of a
mosquito or other insect. It tends to infest
the lymph nodes and prevent drainage of
lymph . This results in swelling and gross
disfiguration of genitals and legs. These
worms are common in most tropic and
subtropic regions. The condition is
endemic in Central Africa and Southern
South East Asia.
Elphantiasis
affecting left leg and genitals
• Worm infection is characterized by
occlusion of lymph vessels. There is
swelling and pain of the limb that is distal to
the blockage. After many years the limb
may become grotesquely swollen and the
skin coarse and tough.
• Oral medication is available for treatment.
The most effective means of preventing
filarial infestation is mosquito and insect
control.
Intestinal helminthes
cause infestations in
intestinal tract and
abdominal organs such
as the liver and spleen.
Always in pairs.
• Treatment for intestinal helminthes
generally consists of taking antiparasitic
drugs.
Helminthes which
have infested the
liver.
hepatomegaly and
ascites
Intestinal Roundworms
Mass of 800 worms removed from child’s
ileum during autopsy
• The intestinal roundworm, ascaris
lumbricoides (as-kah-ris lum-brih-koydees), is a giant helminth. The ascaris
spends its larval and adult stages in humans.
Later, it releases eggs in human feces,
which can be spread to other humans
through food, drink, or soiled items placed
in the mouth.
• Treatment consists of taking antiparasitic
drugs.
Loa Loa eye worm infestation in
conjunctiva
• The loa loa is a parasitic worm of western
and central Africa. It is also be referred to
as the “eye worm”. In this picture, the
worm is just under the conjunctiva of the
eye.
Loa loa being extracted from under
conjunctivia.
Hydatid cyst formed by tiny tapeworm that
migrated to brain.
• This dangerous tapeworm, Echinococcus
granulosus, lives in the intestinal tract of
carnivorous animals (e.g. dogs, wolves).
Humans become infected from contact with
the feces of animals that had eaten flesh of
sheep or deer containing the cyst form of
the tapeworm. This disease is more
commonly seen in people who hunt and trap
wild animals or raise livestock.
Summary
•Microbes are microscopic organisms
•About 100 trillion microbes live on the
average human
•“Bad” microbes are pathogens
•About 3% of microorganisms are
pathogenic
•Main classes of pathogenic microbes
include: bacteria, fungi, viruses, protoza,
& helminths
That’s all folks.