Transcript FUNGI - Pima Community College : Home

Microbiology 205
Georgetta Seidel
Definitions
• Mycologists--scientists who
study fungi
• Mycology--scientific
discipline dealing with fungi
• Mycoses--diseases caused in
animals by fungi
The five kingdom system
• Eukarya (includes all organism with a
nucleus & membrane bound organelles)
• Plants and Animals are fairly obvious
• Fungi, are very distinct from the other
kingdoms
• Kingdom Protista is a “dumping
ground” for organisms that don’t fit into
the other eukaryotic kingdoms
Exoenzymes are found in fungi and some bacteria. They are digestive
enzymes that are secreted into the environment, where they digest the
food into small molecules that can be absorbed and used by the fungus.
• FUNGI
• 100,000 species
• 100 human pathogens, fungi associated
diseases are rising, due to nosocomial
infections and in immunocompromised
patients (ie. HIV, diabetes, lupus,
transplant folks)
• Aspergillosis, Blastomycosis—
pulmonary infections and dissemination
may be involved
• 5,000 plant pathogens=$1 billion/yr
IMPORTANCE OF FUNGI
• Fermentation industry
• Remember fermentation is an anaerobic process
- Wine (yeast)
- Beer
- Bread
- Cheese (bacteria)
- Soy sauce (filamentous fungi (Aspergillus oryzae
provides a low protein diet with amino acids, yeast
& bacteria) soy beans & flour are held in a
container for mold to grow—moldy beans are
incubated for several months
- Sauerkraut
- Vinegar (yeast and bacteria)
- Yoghurt (Bacteria)
IMPORTANCE OF FUNGI
• Drug manufacturing (usually their
waste products are to our benefit)
– Citric acid
–Ethanol (yeast)
–Antibiotic griseofulvin, penicillin
– Cortisone (Rhizopus)
– immunosuppressive agents
(cyclosporine)
IMPORTANCE OF
FUNGI (cont.)
• SAPROPHYTE
• Degrade complex organic
materials into simple ones,
which become available for
other organisms
Importance of Fungi (cont.)
• MYCORRHIZAE
• Fungi associated with plants
Symbiosis
• Fungi help plant roots absorb
minerals and water in the soilserve as root extensions
• Fungi benefit by absorbing
nutrients exuded by plant roots
• They are often called “ancient
plants”
• 4 broad classes exist
• Algal fungi
• Sac fungi
• Imperfect fungi
• Club (basidium) fungi
Algal fungi
• All are microscopic and grow in
water and damp soil
• Many species in this group are
responsible for blights (like Irish
Potato Famine)
• Some species, such as Rhizopus
however, are used as a source of
cortisone and other "drugs"
Sac fungi
yeasts and the blue and green molds often seen on
decaying citrus fruits, in jellies and on leather
• Some species, like Penicillium are economically
useful, but others such as Ergot (Clavicep s
purpurea) which infects rye crops, can cause mass
destruction
•
• In controlled doses, however, Ergot becomes an
important alkaloid used to control hemmorrage
(during the birthing process) as well as in the
treatment of migraine
• Candida albicans is another species of sac fungi that
is parasitic in human beings and aids in the normal
functioning of the digestive tract
Imperfect fungi
• molds that mildew walls and
spot clothes, as well as those
that cause plant diseases,
athlete's foot, and ringworm.
• Some of these fungi are useful
like Aspergillus, used in the
production of miso (fermented
soy paste)
Club (basidium) fungi
• largest group of fungi which
includes rusts and smuts that attack
specific plants, such as corn,
beans, apples, wheat, asparagus,
coffee, roses and barberry
• many of the mushrooms in this
division are edible and delicious, a
large number of them, such as the
Amanita's are deadly poisonous
FUNGAL STRUCTURE
• Thallus-”body”
–Molds & fleshy fungi have these
structures
•Long filaments of cells (hyphae)
•Septate-Cross Wall (Most
Fungi)
•Coenocytic-No cross wall,
continuous mass with many
nuclei
MYCELIUM
• Intertwined filamentous mass
formed by hyphae, visible to
the unaided eye
• Forms when environmental
conditions are right
YEAST
Facultative Anaerobes
• Fermentation=ethanol and CO2
• Non-filamentous unicellular
fungi
–Spherical or oval
• Reproduction
–Two types exist
–a)Fission or b) budding
Yeast Reproduction
• FISSION
• “even” reproduction, nucleus divides
forming two identical cells, like
bacteria
• BUDDING
• “uneven” reproduction, parent cell’s
nucleus divides and migrates to form
a bud and then breaks away
DIMORPHIC FUNGI
• Growth as a mold or as a yeast
• Most pathogenic fungi are
dimorphic fungi
• At 37o C yeast-like
o
• At 25 C mold-like
• Can also occur with changes in
CO2
• Fungi grow differently in tissue vs
nature/culture; often dictated by
temp
Changes in CO2
Within Agar=mold, Agar Surface=yeast
Types of REPRODUCTION
• Asexually-fragmentation of hyphae
• Asexually and Sexually-spores
–Spores: Used for Identification
Four groups of true fungi
–Zygomycetes (common bread mold—
Rhizopus)
–Basidiomycetes (puffballs & common
mushrooms)
–Ascomycetes (Dutch elm disease/rye smut)
–Deuteromycetes (fungi imperfecti)
Classification of these groups
• First three groups is based
on their method of sexual
reproduction
th
• 4 group, the
Deuteromycetes, have
NO sexual reproduction
REPRODUCTION (cont.)
• Asexual Reproduction
• Progeny will be identical to
parent
–Spores (Conidiospores,
Blastospores,Chlamydospores,
Sporangiospores)
–Hyphae fragmentation
(Arthrospores)
IDENTIFICATION OF FUNGI
• Examination of asexual spores
• **Fungal spores are different than the
endospores of bacteria
• Endospores are not for reproduction,
but an environmentally resistant life
stage
• Fungal spores are for reproduction, do
not ensure resistance to environmental
conditions
Asexual spores
• Conidiospores
• Chlamydospores
• Sporangiospores
• Blastospores
ASEXUAL SPORES
Conidiospore
–Multiple (chains) or single spores
formed at the end of an aerial hypha
–Not enclosed
within a sac
–Aspergillus spp.
–Penicillium spp.
Conidial fungus
• reproduces by means of
asexual spores called conidia
• Conidia vary greatly in shape,
size and color
• Most of the common
household molds & mildews
are conidial fungi
ASEXUAL SPORES (cont.)
• Another type of Conidiophore:
• Blastospores
–A bud coming off the parent cell
– Candida
albicans
Blastospore
Blastospores
ASEXUAL SPORES (cont.)
• Chlamydospore
–Formed within hypha
–Thick-walled spore
• Candida albicans
Chlamydospores
• The chlamydospore is a method of
producing a substantial resting
spore very quickly
• Nutrient is shunted from adjacent
cells into a preferred cell and it
swells up, converts nutrient
materials to oil droplets for
efficient storage, then rounds off
with a thick, often roughened outer
wall for protection
Chlamydospores
ASEXUAL SPORES
• Sporangiospores
–Hundreds formed within a
sac (sporangium) at the end
of an aerial hypha
–Rhizopus spp.
Rhizopus spp
Arthrospores
1A
2
Chlamydospores
1
Conidiospores
3
Sporangiospores
1B
Blastospores
NUTRITIONAL
ADAPTATIONS
• Acidic pH (5.0)
• Most molds are aerobic
• Yeasts are facultative
anaerobes
NUTRITIONAL
ADAPTATIONS (cont.)
• High osmotic pressure
• Low moisture
• Less N2 than bacteria
• Complex carbohydrates
–Lignin(component of
wood) *Saprophytes
MEDICALLY
IMPORTANT FUNGI
part II
(Some characters used in identification
of deuteromycetes)
ALL FUNGI:
•
•
•
•
are eukaryotes
develop from spores
display neither flagella, cilia, nor chloroplasts
have cell walls (though not necessarily ones
composed of cellulose as are plant cell walls, but
instead of chitin and other polysaccharides)
• Though displaying great variety and complexity,
the fungi are routinely divided into two major
groups:
• the macroscopic (fleshy) fungi
• the microscopic fungi (molds and yeasts)
Fungal growth requirements
•
–
–
–
–
–
In contrast to bacteria, fungi
tend grow in places that are:
more acidic
have higher osmotic pressures
are lower in moisture
are low in nitrogen
contain complex
carbohydrates
Fungal structures
Hyphae are one dimensional
arrangements of cells.
• septa are the cross walls which
separate individual cells in
hyphae.
•
Mycelium are a tangled mass of
hyphae.
• Mycelium can extensively
permeate the substrate within
which the fungi grows whether
it be soil, water, or even living
tissue.
Molds vs Yeast
•
•
•
•
–
–
–
–
Molds
Molds are aerobic, filamentous fungi including
mildews
rusts
smuts
Molds tend to grow on surfaces rather than
throughout substrates.
Yeasts
unicellular/nonfilamentous:
•
Yeasts are fungi which are:
•
typically spherical or oval
•
facultatively anaerobic
•
They are often observed as powdery
coatings on plant material.
Dimorphic fungi
• Dimorphic fungi are fungi that
behave like molds
(multicellular---consist of
hyphae) under some conditions,
and like yeasts (unicellular--lack hyphae) under others.
Review
Fungal reproduction
•
•
–
–
–
–
fungi replicate by mitosis rather
than the binary fission
employed by bacteria.
Types of fungal reproduction, :
budding
fission
hyphae fragmentation
sporulation
Sexual and asexual:
Fungal spores come in two varieties:
asexual spores and sexual spores
–
Spores are used extensively to identify fungi.
•
Asexual spores
–
asexual spores are formed by a single parental
fungi and therefore genetically identical to the
parental fungi.
–
Asexual spores come in a variety of types
formed by a variety of mechanisms including:
•
Arthrospores (sliced bread pieces)
•
Blastospores (buds on a twig)
•
Chlamydospores (giant cell with oil)
•
Conidiospores (fingers)
•
Sporangiospores (sac)
Ascomycetes
• Asexual phase- Conidiospores
(Penicillium and Aspergillus &
budding yeast
• Sexual phase (morels
lichens)
Zygomycetes
• Asexual phase—Sporangium—bread
mold (Rhizopus stolonifer)
• Sexual phase--- sporgangium --shotgun fungus (lives on dung) it
shoots its sporgangium explosively
towards light or fly pathogen
(Entomophthora muscae—--these
types of fungi have been used as
agents for biological control of
insects)
Basidiomycetes
• Basidiospore
• Examples: boletes,
puffballs,smuts, stinkhorns
and tooth fungi
DEUTEROMYCETES
(cont.)
–Aspergillus
–Blastomyces
–Candida
–Histoplasma
- Microsporum
(dematophytes)
- Penicillium
- Trichophyton
- Pneumocystis ?
Zygomycetes
• “saprophytic” molds
• common bread mold
(Rhizopus)
• coenocytic hyphae
• Asexual spores:
Sporangiospores
Approximately 600 species including bread molds
(such as Rhizopus) exist
Ascomycetes
• “sac” fungi
• Septate hyphae and yeasts
• Asexual spore:
–Conidiospores
Approximately 30,000 species including yeasts
(Saccharomyces cerevisiae), some of the molds
(Aspergillus), morels, and truffles. Ascomycetes have
typical reproductive structures called asci.
Basidiomycetes
• “club”fungi
• Mushrooms
Approximately 25,000 species including many
macroscopic fungi (mushrooms, puffballs, shelf fungi)
as well as a number of plant pathogens (rusts, smuts).
FUNGAL DISEASES
• Mycosis: Fungal infection
• Usually chronic
• Four groups of mycoses
based on degree of tissue
involvement and mode of
entry
Because fungi are slow growing, mycoses are generally
long-lasting
TYPES OF MYCOSES
• Systemic
• Subcutaneous
• Cutaneous
• Opportunistic
SYSTEMIC MYCOSES
• Deep within the body
–effects a number of different
tissues and organs
• Usually soil fungi
• Spore inhalation=Route of
transmission-starts in the lungs and
spreads to other body tissues
• Not contagious
SYSTEMIC MYCOSES
(cont.)
• Histoplasmosis
• Coccidiomycosis
• Coccidioides immitis got renamed for the
AZ Valley fever Coccidioides posadasii
SUBCUTANEOUS
MYCOSES
• Infections beneath the
skin
• Soil and plant fungi
• Hyphae or spores in
wounds
CUTANEOUS MYCOSES
• Called “Dermatophytes”
• Epidermis
• Hair
• Nails
• Secrete keratinase-degrades keratin
(protein found in hair, skin and nails)
• Contagious-direct contact with
infected hairs and epidermal cells
CUTANEOUS MYCOSES
• Skin high osmotic
pressure
• Low moisture
OPPORTUNISTIC MYCOSES
• Broad-spectrum antibiotics
• Transplant patients
• AIDS patients
• Cancer patients
–Ex: Stachybotrys (mold),
Mucormycosis and
Aspergillosis
DERMATOPHYTES
• Grow on keratin
–Hair
–Nails
• Tinea or
ringworm
TINEA
• Capitis (scalp)-can lead to
bald patches
• Cruris (groin)
• Pedis (athlete’s foot)
FUNGI IN CUTANEOUS
MYCOSES
• Three genera involved in
cutaneous mycoses:
• Trichophyton
• Microsporum
• Epidermophyton
TRICHOPHYTON
• Hair
• Skin
• Nails (Tinea ungulum)
MICROSPORUM
• Hair
• Skin
EPIDERMOPHYTON
• Skin
• Nails
Fungi in Cutaneous Mycoses
Trichophyton
Microsporum
Epidermophyton
Hair
Hair
Skin
Skin
Skin
-
Nails
-
Nails
Tinea capitis
Tinea capitis
Tinea barbae
Tinea cruris
Tinea unguium
Tinea pedis
SUBCUTANEOUS
MYCOSES
• More serious than
cutaneous mycoses
• Sporothrix schenkii
–Soil organism
• Gardeners=ulcers on
hands
Subcutaneous mycosis (mycetoma)
Mycetoma
• Mycetoma is a chronic infection of the skin,
subcutaneous tissue and sometimes bone
• It is generally found on the foot where it is given the
name watering can foot
• Mycetoma may be due to several fungi or
actinomycetes (actinomycetoma).
• Actinomycetes are bacteria producing filaments like
fungi. Both the fungi and the actinomycetes are found
in soil and plant material in tropical regions.
• The organism is inoculated into the skin by a minor
injury, for example, a cut with a thorn when barefoot.
Mycetoma—a deep fungal infection
Clinical features
• Mycetoma is more common in men than women,
particularly those aged 20 to 50. It generally presents as a
single lesion on an exposed site and may persist for years.
• It starts as a small hard painless lump under the skin.
• It grows slowly but eventually involves underlying muscles
and bones.
• The middle of the lesion caves in, ulcerates and discharges
pus, which contains grains.
• Eventually, sinus tracts (holes) develop which also
discharge pus and grains.
• The surface skin is scarred and pale.
• Considerable deformity often makes it difficult to walk.
• Mycetoma may cause no discomfort but it often itches or
burns.
• Secondary bacterial infection is common.
• Treatment is slow
CANDIDIASIS
• Mucosal normal
microbiota suppresses the
growth of Candida
albicans
CANDIDIASIS (cont.)
• Vaginitis and thrush are initiated
by:
–Antibiotics eliminate normal
microbiota
–pH changes
• Infants that may not have their
normal microbiota
established=thrush
Candidiasis
Thrush
Vaginal
CANDIDIASIS (cont.)
• Hematogenous dissemination
•Kidney
•Spleen
•Lung
•Liver
Invasive candidiasis
MYCOSES OF THE
RESPIRATORY SYSTEM
• Histoplasmosis-resembles
TB, starts in the lungs, most
cases are minor
–Histoplasma capsulatum
• Coccidioidomycosis
–Coccidioides immitis in CA
–Coccidioides posadasii in AZ
MYCOSES OF THE
RESPIRATORY SYSTEM
(cont.)
• Blastomycosis
–Blastomyces dermatidis
• Pneumocystis pneumonia
–Pneumocystis carinii
HISTOPLASMOSIS
• Resembles tuberculosis
• May affect all organs
• Vague symptoms
• Yeast lives within
macrophages and multiplies
HISTOPLASMOSIS
(cont.)
• Histoplasma capsulatum
• Dimorphic fungi
• Mississippi river and Ohio
river states
HISTOPLASMOSIS (cont.)
• Very low mortality
–50/year/USA
• Transmission
–Airborne conidia
–Bats: Carry fungus in feces
–Birds: Feces
HISTOPLASMOSIS
(cont.)
• Diagnostic
–Blood test—AB titer
• Treatment
–Amphotericin B
–Itraconazole
Histoplasmosis
• second most significant fungus disease
• It is infectious but not contagious
• The "summer flu" that Midwesterners use to get
often is now thought to have been
histosplasmosis
• Histoplasmosis basically is a pulmonary or
respiratory disease, but may extend to the liver,
lymph nodes, and spleen; it may disseminate to
the blood and bone marrow and be fatal
• The victim frequently has chills and fever to 105
degrees, night sweats, chest pains, and fatigued.
A non-productive cough is fairly common.
Histoplasmosis
COCCIDIOIDOMYCOSIS
• Valley fever
–Coccidioides immitis
–Coccidioides posadasii
–Dimorphic fungi
COCCIDIOIDOMYCOSIS
(cont.)
• Southwest deserts
–Arthrospores in dry
alkaline soils
–San Joaquin Valley (CA)
–Tucson area
RANGE OF CASES OF
VALLEY FEVER:
inapparent -- 60%
mild - moderate --30%
complications -- 5-10%
fatal--<1%
COCCIDIOIDOMYCOSIS
(cont.)
• Symptoms
–Chest pain
–Fever
–Cough
–Extreme fatigue
RISK FACTORS FOR DISSEMINATED DISEASE:
Immunosuppressed Patients-organ transplant
lymphoma
HIV+/AIDS
adrenal corticosteroid therapy
diabetes
3rd trimester pregnancy
Gender
male
Race
African-American
Filipino
Valley Fever
COCCIDIOIDOMYCOSIS
• In tissues C. immitis forms
spherules
–Thick-walled structures filled
with spores
–In soil, forms filaments that
reproduce by the formation of
arthrospores, transmitted by
wind, 100,000 infections per year
Life cycle of
C. immitis
Spherule form (top half)
multiplies in
the lungs; mycelia
(bottom half)
grow in the soil
C. immitis spherule in lung tissue
Brain lesions
caused
by
C. immitis
Spherules in
brain tissue
COCCIDIOIDOMYCOSIS
(cont.)
• Most infections are
asymptomatic
• Most recover in a few
weeks
COCCIDIOIDOMYCOSIS
(cont.)
• Solid immunity follows
recovery
• 1/1000 cases a tuberculosislike condition develops
throughout the body
COCCIDIOIDOMYCOSIS
(cont.)
• Diagnostic
–Resemblence to TB
requires Identification of
spherules in tissues
–50-100 deaths in the USA
•92% San Joaquin Valley
BLASTOMYCOSIS
• Blastomyces dermatitidis
or North American
Blastomycosis
• Dimorphic fungus
• Soil in Mississippi Valley
BLASTOMYCOSIS
(cont.)
• Most infections are
asymptomatic
• Begins at lungs and
spreads
• 30-60 deaths/year
BLASTOMYCOSIS
(cont.)
• Cutaneous ulcers
• Abscess formation
• Tissue destruction
Blastomycosis—Glichrists
Disease
• Blastomycosis is a chronic, systemic fungal
disease that affects humans
• The disease affects the lungs.
• It is caused by Blastomyces dermatitidis.
• The main route of infection is by inhalation of
spores
• The disease is infectious but is not contagious.
• Major symptoms in humans include loss of
weight, fever, cough, and bloody sputum and
chest pains.
• The disease may disseminate into the skin, bones,
or urogenital tract.
BLASTOMYCOSIS
(cont.)
• Diagnostic
–Isolation of organism
from pus and biopsies
• Treatment
–Amphotericin B
PNEUMOCYSTIS
PNEUMONIA
• Pneumocystis carinii
• Opportunistic pathogen
• Leading cause of death in
AIDS patients
• Present in healthy lungs
• Immunosuppressed
individuals
PNEUMOCYSTIS
PNEUMONIA (cont.)
• Rare before AIDS epidemic
–Less than 100 cases/year
• 1993-Indicator of AIDS
• Currently, one of the most
common infectious diseases
OTHER FUNGAL
RESPIRATORY DISEASES
• Aspergillus fumigatus
• Aspergillus spp.-present
in decaying vegetation
• Rhizopus spp.
• Mucor spp.
•
Those
darn
pigeons!!
Cryptococcosis: Yeast Meningitis
Affects: Humans
The disease is caused by a systemic pathogenic yeast called
Cryptococcus Neoformans, which is found worldwide.
• Cryptococcosis in humans usually begins as a primary infection of the
lungs.
• There are no visible early symptoms may include cough, chest pain,
weight loss, fever or dizziness. The disease may be in the lungs,
mucous membranes, bones, and joints, with no organ or tissue of the
body exempt.
• It very frequently involves the brain covering as cryptococcal
meningitis.
• Pigeon excreta is the most common source of C. Neoformans. The
yeast is carried in the intestinal tract of pigeons.
• Pulmonary cryptococcsis has occurred in the workmen who have been
exposed to the yeast while demolishing old buildings where pigeons
had roosted.
• Most of the cryptococcal infections occur from inhalation of the
fungas along with the dust from areas enriched with pigeons manure.
Other diseases associated with
pigeons
• Salmonellosis is more than just food poisoning.
• Pigeons are important factors in the spread of
salmonellosis, since the bacteria are left wherever
the pigeons defecate
• Pigeons trample back and forth through their
copious excretions on ledges and air intake vents
• The dust enters through air conditioners and
ventilators.
• S. Typhimurium var. Copenhagen is the most
common salmonella isolated from pigeons
• Salmonellosis in humans may manifest itself in
one or more of four types (1) temporary carriage
without infection (2) Gastroenteritis (food
poisoning) (3) enteric fever septicemia (blood
poisoning) (4) Persistent infection
OTHER FUNGAL
RESPIRATORY DISEASES
(cont.)
• Compost piles
–Farmers and gardeners
• Impaired immunity
• Treatment
–Amphotericin B
Antifungal antimicrobials
• Amphotericin B, nystatin
(Streptomyces nodosus)
• miconazole Monistat 3 (azole)
–Relatively toxic-Kidneys
FUNGAL DISEASES OF
THE DIGESTIVE SYSTEM
• Mycotoxins: Fungal
Toxins
–Ergot poisoning
–Aflatoxin poisoning
ERGOT POISONING
• Claviceps purpurea
• Infects Grain Crops
• Ergotism: Disease caused by
ingestion of contaminated
grains
• Claviceps-contaminated grains
(rye or wheat)
Claviceps purpurea
• as recently as 1951, in Pont-St.
Esprit, a small town in France,
there was an outbreak of the
disease. In Europe it is the
custom to buy fresh bread
nearly every day.
• In this small town there was only one bakery and
everyone bought bread from it. Strange things
started happening. People developed a burning
sensation in their limbs, began to hallucinate that
they could fly, did strange things to their dogs with
forks and in general acted weirdly. This outbreak is
chronicled in a marvelous (but out of print) book
called "The day of St Anthony's Fire" by John Grant
Fuller. St. Anthony is the patron saint of lost causes
When all of the other saints have failed, St. Anthony
is the one you are supposed to pray to. And St.
Anthony's fire was rampant in the town that day.
Similar outbreaks probably occurred throughout the
world wherever the conditions were right for the
growth of Claviceps purpurea.
• The chemical responsible for the
hallucinations is actually LSD!
lysergic acid. There was even an
outbreak of ergotism on the
television show "Quincy" starring
Jack Klugman, who played a
coroner. He was aboard a cruise
ship and people were acting very
strangely. Quincy finally traced the
behavior to contamination of the
flour tortillas that had been served
aboard ship.
The X-Files also had an episode
featuring ergot, although it had
a surreal twist (of course). In
that episode, Scully got a tattoo
that caused her to hallucinate
(she thought the tattoo was
talking to her). Turns out the
tattoo artist was an ex-con who
learned his art in prison. He
collected plants in the prison
yard and extracted dyes from
them for his tattoos.
• Another ergot derivative may
cause spontaneous abortions in
animals-- in small doses this
same drug is used to aid in
childbirth. Another of the ergot
derivatives is used to cure
migraine headaches.
ERGOT POISONING
(cont.)
• Gangrene
• Psychotic delusions
• Convulsions
• Abortion
ERGOT POISONING
(cont.)
• Witchcraft in Salem
(1690s)
• Similar Behavior caused
by Lysergic acid (LSD)
• There have been various attempts to explain those
witch trials. None of them are more logical and
interesting than the hypothesis of ergot poisoning,
caused by Claviceps purpurea. The behavior was not
identified as witchcraft until 1691, and this was just
the beginning of the problem.
• All of the accused had similar symptoms: manic
melancholia, psychosis, delirium, crawling sensations
of the skin, vertigo, headaches, vomiting and diarrhea
All of these are symptoms of ergot poisoning, and it is
likely that at least the initial hysteria was started by
Claviceps purpurea infecting the grains of rye
• compelling, although circumstantial, evidence that the
Salem witch trials coincided with a weather period
that would have produced large quantities of ergot on
rye, which was grown in the lowlands in that area.
Aflatoxin
•Aflatoxin is a naturally occurring mycotoxin produced by two
types of mold Aspergillus flavus and Aspergillus parasiticus.
•Aspergillus flavus is common & widespread in nature and is
most often found when certain grains are grown under
stressful conditions such as drought.
•The mold occurs in soil, decaying vegetation and hay
•At least 13 different types of aflatoxin are produced in nature
with aflatoxin B1 considered as the most toxic
•While the presence of Aspergillus flavus does not always
indicate harmful levels of aflatoxin it does mean that the
potential for aflatoxin production is present.
Aflatoxin poisening
• Aspergillus flavus
• Peanuts and cottonseeds
• Acute intoxication
–Liver damage
AFLATOXIN POISONING
(cont.)
• Chronic intoxication
–Liver cancer
–Depending on the levels, the
toxins can severely affect the
liver and they are a known
human carcinogen