NAME: WASWA WALTER WAKHUNGU

UNIVERSITY: PWANI UNIVERSITY

ADM.NO. : SG26/PU/36067/16

COURSE: MASTERS OF SCIENCE [MICROBIOLOGY]

DEPARTMENT: BIOLOGICAL SCIENCE

SCHOOL: SCHOOL OF PURE AND APPLIED

UNIT: ADVANCED MYCOLOGY

UNIT CODE: SBT G805

LECTURER: DR. JOYCE JEFWA

ASSIGNMENT: Economic and practical food and beverage, Health applications of mycology

A. Food sources

B. Fermenters C. Wine And Beer Making

D. Leavening Agent E. Natural Food Flavor And Color F. Drugs

G. Human Disease

Date : 24/11/2016

A. FOOD

1. Protein source

A large range of edible fungi are cultured. Agaricius bisporus is cultivated widely in western

countries. In addition, Shii-take (Lentinus edodes), Straw mushroom (Flammulina velutipes),

Oyster mushroom (Pleurotus ostreatus), and Chinese Black mushroom (Auricularia polytricha)

are cultured in various Asian countries, and increasingly in western countries. The truffle

industry is economically important in southern Europe and production is expanding in the

southern hemisphere. Finally, edible mushrooms are picked from the wild, especially in Europe.

Many of the fungi are eaten fresh, but there is also a market for dried mushrooms and canned

truffles.

Fungi are ideal food becoming an ideal source of myco-protein , healthy alternative to meat.

They have a fairly high content of protein (typically 20-30% dry matter as crude protein) which

contains all of the essential amino acids. Fungal biomass is also a source of dietary fibre, and is

virtually free of cholesterol. Mushrooms are cultivated around the world, global annual

production being in the region of 8 million metric tones eg Agaricus spp, the mycelium of a

species of Fusarium.

The morel is not commonly seen in shops. The ascocarp is hollow and delicate. The structure is

pointed and rarely higher than 10cm. © Dave Powell , USDA Forest Service. Image 0808042.

http://www.ipmimages.org.

Pleurotus ostreatus, also known as Oyster mushroom. © Robert L. Anderson, USDA Forest

Service. Image 0590031. http://www.ipmimages.org.

Fruiting body of Auricularia. This fungus is found on the dying branches of trees throughout the

University grounds.

B. FERMENTER

1. Soy Sauce

We tend to take a variety of foods and food additives for granted, without being aware of the

processes which get them to the table. One such food is Soy Sauce and its partner bean curd.

Soy sauce (shoyu) is a dark brown, salty liquid, high in amino acids and with a meat-like flavour.

It was first produced in Japan (a similar product is made in other east Asian countries), where

some microbial cultures were used to ferment the unpalatable soy beans. The current industrial

process is highly controlled, used around the world and is based on this original process.

Fermentation is in two stages. Initially, soy beans are soaked, cooked to remove contaminants,

and then mixed with roasted wheat. The fungus Aspergillus oryzae is added to the mix, and the

amended mix kept aerobically for 20 to 40 hours at 25 C. The fungus produces invertases,

amylases and cellulases, which degrade the soy paste. The paste is then mixed and taken into the

second phase of fermentation.

In deep vats, brine is added to the paste and the yeast Saccharomyces rouxii and lactobacilli are

added. Anaerobic conditions develop quickly, preventing further growth of A. oryzae. After

about a month, a sour liquid is apparent. The liquid contains large concentrations of amino acids,

simple sugars and a range of vitamins. After separation and further storage, the liquid is

sterilised, bottled and sold as Soy Sauce. Similar products are called Koji, Idli, Patu, Laochao or

Ogi.

2. Cheese

Production of cheese relies on diverse microbes. The cheese environment is dynamic and the

specific biological interactions complex. Fungi play a role in ripening in two different ways: they

may assist ripening from the outside of the cheese, and they can impart flavours from inside the

cheese.

Various yeast and filamentous fungi colonise the surface of cheeses. The may be surface

contaminants or deliberately inoculated. Their impact will rely on the temperature, water content,

pH, salinity and redox of the substrate.

Soft-ripened cheeses are ripened from the outside in. Penicillium camemberti (=P candidum) is

inoculated onto the surface of cheeses, typically Brie, Camembert and Neufchatel, where growth

over 7 to 70 days imparts a flexible powdery white crust and contributes to the runny texture and

intense flavours of the contents.

Various cheeses are sold that have been stab-inoculated with a strain of Penicillium roquefortii.

The result is a blue streak or vein through the cheese. The fungus imparts a strong, pungent

flavour due to the aerobic production of methyl ketones. Famous blue cheeses include:

Roquefort, Gorgonzola, Stilton, and Danish Blue. The fungus is a widespread spoilage organism

found in cool conditions. It can grow at low oxygen availability and tolerates acidic conditions.

Thus the presence of blue cheeses in your fridge may lead to widespread contamination of

products like bread that use acids as preservatives.

Cheese is susceptible to the growth of fungi. While a huge diversity are associated with

unwanted contamination, some such as Geotrichum candidum have been expoited because they

are thought to impart desirable flavours and assist with the ripening process.

Wine and Beer Making

Although there is a distinction between beer, wine and liquor as well as other lesser known

alcoholic beverages, they share one thing in common. They are the fermentation products of

yeasts, mostly Saccharomyces cerevisiae or in the case of beers, usually S. carlsburgiensis.

Yeasts, as you recall, are not mycelial. They are unicellular fungi that reproduce asexually by

budding or fission. The reaction by which alcoholic beverages are produced is generally referred

to as fermentation and may be summarized as:

Yeast + Glucose è Alcohol (Ethanol) + CO2

This reaction is also important in baking bread, but the desired product is then the carbon dioxide

rather than alcohol. The production of alcohol occurs best in the absence of oxygen. However,

from the yeast's point of view, alcohol and carbon dioxide are waste products, and as the yeast

continues to grow and metabolize in the sugar solution, the accumulation of alcohol will become

toxic when it reaches a concentration between 14-18%, thereby killing the yeast cells. This is the

reason why the percentage of alcohol in wine and beer can only be approximately 16%. In order

to produce beverages (liquor) with higher concentrations of alcohol, the fermented products must

be distilled. With the genetic manipulation of yeasts, numerous varietal strains have been bred.

This, along with modifications in the brewing process have led to different types of beers. Those

most often seen in North America include:

Lager. Beers made with yeast that settle on the bottom (Saccharomyces carlsbergensis)

of the container used. Thus, all the yeast and other material settles on the bottom which

results in a clear beer. Most American beers are lagers.

o Pilsner. A colorless lager beer originally brewed in the city of Pilsen. Water used

for this style of beer tend to be harder, with a higher calcium and magnesium

content than water used for lager. The color of pilsner is also lighter than that of

lager beer.

Ale. Beers made with yeast that floats (Saccharomyces cerevisiae) to the top of the

brewing vats, resulting in a cloudier beer. They tend to have a higher alcohol content than

lagers.

o Stout. A very dark, almost black ale. The dark color and roasted flavor is derived

from the roasted

barley, and/or roasted malt. Beer historians consider it to be the descendant of the

Porter ale.

o Porter. A very dark ale. The darker color and special flavor comes from toasting

the malt before brewing. This usually results in a stronger taste and higher alcohol

content. Considered by beer historians to have evolved into the Stout ale.

C. LEAVENING AGENT

Baker's yeast is the common name for the strains of yeast commonly used as a leavening agent in

baking bread and bakery products, where it converts the fermentable sugars present in the dough

into carbon dioxide and ethanol. Baker's yeast is of the species Saccharomyces cerevisiae

D. FOOD ODOR AND FLAVOR AND FLAVOR

Fungus is primarily responsible for the production of some characteristic odour, flavour, or

texture and may or may not become part of the final edible product. Growing filamentous fungi

on water-soakedseeds of plants is the basis for production of several human food products in

Asia, including soy sauce and various other fermented foods. In soy sauce production soybeans

are soaked, cooked, mashed and fermented with Aspergillus oryzae and A. sojae. Depending on

the size of the factory, the soybeans may be fermented in fist-sized balls (the traditional method)

or on trays. When the substrate has become overgrown with the fungus the material is mixed

with salt and water and the fermentation is completed in the brine. The biggest industrial units

today use a continuous process in which defatted soybean flakes, moistened and autoclaved are

mixed with ground, roasted wheat. The mixture is turned mechanically to ensure even growth of

Aspergillus oryzae and A.sojae for two to three days; then it is transferred to brine and

inoculated with Pediococcus halophilus and 30 days later with Saccharomyces rouxii. The brine

fermentation takes six to nine months to complete, after which the soy sauce is pressure-filtered,

pasteurised and bottled.

While many flavours are produced by bacteria, fungi are responsible for a range of flavours

including terpenes, menthol and lactones. Fungi also produce compounds that deodorise

offensive and neutralise bitter flavours. At present, flavour enhancement is an unimportant area

of the industrial use of fungi.

Colours

Fungi produce a range of compounds that alter the colour of food. For instance, Monoascus

purpureus has been traditionally used for the production of red wine. The pigments are

polyketides that are insoluble in acid conditions. Beta carotene is produced by a range of

Mucorales. This can be added to a variety of foods. Concern with the potentially toxic or allergic

characteristics of some artificial colours has led to a closer examination of colours from natural

sources.

E. DRUGS

Fungi make an extraordinarily important contribution to managing disease in humans and other

animals. At the beginning of the 21st century, Fungi were involved in the industrial processing of

more than 10 of the 20 most profitable products used in human medicine. Two anti-cholesterol

statins, the antibiotic penicillin and the immunosuppressant cyclosporin A are among the top 10.

Each of these has a turn over in excess of $1 billion annually. Drug discovery continues. The

following have recently been approved for human use: Micafungin is an antifungal agent;

mycophenolate is used to prevent tissue rejection; rosuvastatin is usd to reduce cholesterol; and

cefditoren as an antibiotic Antibiotics From Fungi

In 1941, penicillin from the fungus Penicillium chrysogenum was first used successfully to treat

an infection caused by a bacterium. Use of penicilin revolutionised the treatment of pathogenic

disease. Many formally fatal diseases caused by bacteria became treatable, and new forms of

medical intervention were possible.

When penicillin was first produced, the concentration of active ingredient was approximately 1

microgram per ml of broth solution. Today, improved strains and highly developed fermentation

technologies produce more than 700 micrograms per ml of active ingredient.

In the early broths, several closely related molecules were present. These molecules are beta

lactam rings fused to five-membered thiazolidine rings, with a side chain. The side chain can be

chemically modified to provide slightly different properties to the compound.

The natural penicillins have a number of disadvantages. They are destroyed in the acid stomach,

and so cannot be used orally. They are sensitive to beta lactamases, which are produced by

resistant bacteria, thus reducing their effectiveness. Also, they only act on gram positive bacteria.

Modifications to manufacturing conditions have resulted in the development of oral forms.

However, antibiotic resistance among bacteria is becoming an extremely important aspect

determining the long-term use of all antibiotics.

Cephalosporins also contain the beta lactam ring. The original fungus found to produce the

compounds was a Cephalosporium, hence the name. As with penicillin, the cephalosporin

antibiotics have a number of disadvantages. Industrial modification of the active ingredients has

reduced these problems.

The only broadly useful antifungal agent from fungi is griseofulvin. The original source was

Penicillium griseofulvin. Griseofulvin is fungistatic, rather than fungicidal. It is used for the

treatment of dermatophytes, as it accumulates in the hair and skin following topical application.

More recently, several new groups have been developed. Strobilurins target the ubihydroquinone

oxidation centre, and in mammals, the compound from fungi is immediately excreted.

Basidiomycetes, especially from tropical regions, produce an enormous diversity of these

compounds.

Sordarins are structurally complex molecules that show a remarkably narrow range of action

against yeasts and yeast-like fungi. The compounds inhibit protein biosynthesis and so may

become important agents against a number of fungal pathogens of humans.

Echinocandins are cyclic peptides with a long fatty acid side chain. They target cell wall

formation. Semi-synthetic members of the group of compounds include pneumocandins which

are in use in humans.

Immune Suppressants

Cyclosporin A is a primary metabolite of several fungi, including Trichoderma polysporum and

Cylindrocarpon lucidum. Cyclosporin A has proven to be a powerful immunosuppressant in

mammals, being widely used during and after bone marrow and organ transplants in humans.

Cyclosporin A is a cyclic peptide consisting of 11 mainly hydrophobic amino acids. Its inhibition

of lymphocytes was first discovered during the 1970s. Subsequently, the mode of action was

elucidated.

Cyclosporin A binds to a cytosolic protein called cyclophilin. Cyclophilin is found amongst

many different organisms and its form appears highly conserved. Cyclophilin is involved with

folding the protein ribonuclease. However, the Cyclosporin A/cyclophilin complex also binds to

calcineurin. Calcineurin dephosphorylates a transcription factor, thereby triggering transcription

of numerous genes associated with T cell proliferation. When the complex binds to calcineurin,

T cell proliferation is suppressed. The inhibition of T cells proliferation results in the suppression

of the activation process associated with invasion by foreign bodies. As a consequence,

transplant tissues, which are foreign bodies, are not rejected.

Calcineurin is also highly conserved amongst phylogenetically diverse organisms. In fungi such

as the human pathogen Cryptococcus neoformans, calcineurin is necessary for recovery from cell

cycle arrest, growth in hypertonic solutions and regulation of the calcium pump. Thus the

interaction of the Cyclosporin A/cyclophilin complex with calcineurin in Cryptococcus will

result in death of the pathogen. However, in humans, cyclosporin also suppresses the immune

system. The side effect is an unacceptable risk, and Cyclosporin A is not used as a fungicide in

humans at present.

Gliotoxins also have immunological and antibiotic activity. Produced by many fungi including

Aspergillus fumigatus, gliotoxins belong to a class of compounds called

epipolythiodioxopiperazines. The antibiotic activity is widely recognised and considered

uninteresting. However, its effect on the immune system, especially macrophages, is being re-

examined.

A wide range of other compounds with antibiotic activity are also known. They have been

rejected for use in medicine because of unwanted side effects, or instability of the active

compound.

Ergot Alkaloids

Claviceps purpurea is the causal agent of St Anthonies fire, a scourge of the middle ages when

ergots contaminated flour. The ergots contain many alkaloids. Their effects are quite variable.

They act on the sympathetic nervous system resulting in the inhibition of noradrenaline and

sclerotin, causing dilation of blood vessels. They also act directly on the smooth muscles of the

uterus causing contractions, thus their early use to induce abortion. Their strongest effect is

intoxication, caused by lysergic acid amides, one of which is the recreational (and illegal) drug,

LSD.

Seeds of Paspalum replaced by C. paspalli.

Ergot alkaloids have a number of medicinal uses. Perhaps the most widespread use is in the

treatment of migraines. The vasodilator activity reduces tension during an attack. The drugs also

reduce blood pressure, though with untoward side effects. Alkaloids are now produced in culture

by strains of C. fusiformis and C. paspalii.

Statins

Aspergillus terreus, a soil-borne fungus, produces a secondary metabolite called lovastatin and

Phoma sp produces squalestatin. Statins have been used to reduce or remove low density

lipoproteins from blood vessels in humans. In fact, the compounds all act via an enzyme in the

liver that makes cholesterol, lovastatin inhibits HMG CoA reductase and squalestatin inhibits

squalene synthase. By blocking the enzyme, the body removes cholesterol complexes from the

inside of blood vessels. This has the effect of reducing or removing blockages in arteries, and

thereby reducing the chance of a heart attack, strokes and diabetes.

In addition, statins have been implicated in attracting stem cells to damaged tissues. The stem

cells then appear to regenerate the tissue.

Some statins induce problems. One form of the drug has been associated with muscle wastage.

Others appear to lack side effects and have been recommended for wide spread use to control

heart disease.

F. FUNGAL DISEASES IN HUMANS

According to CDC fungi are everywhere. There are approximately 1.5 million different species

of fungi on Earth, but only about 300 of those are known to make people sick.

Fungal diseases are often caused by fungi that are common in the environment. Fungi live

outdoors in soil and on plants and trees as well as on many indoor surfaces and on human skin.

Most fungi are not dangerous, but some types can be harmful to health.In discussing fungal

diseases, the most convenient way of classifying them is to categorize them according to the type

of infection that has occurred: 1. Superficial infections, are caused by fungi that attack the skin

or its appendages (nail, feathers and hair). Some examples of these infection include ringworms,

jock-itch and athlete's foot. These fungi are known as dermatophytes. 2. Systemic infections,

diseases that occur deep within the tissues, involving vital organs and/or the nervous system, and

which may be fatal, but may also be chronic. Entry into the body is usually through inhalation of

spores or open wounds. Blood circulation or respiratory system may then transmit fungus

throughout body and additional infection of internal organ may occur. These fungi, are usually

saprotrophic fungi, growing in the soil. A third, Intermediate infection, is sometimes also

recognize and is intermediate between the two just discussed. The infection will occur below the

skin, but will remain localized

Superficial Infections

The superficial mycoses are the most well known since they can be readily observed. They

commonly occur on the hair, nails and skin of infected individuals. They have been recorded in

various compilations of medical literature for well over a thousand years as ring worm, athlete's

foot, jock itch and piedra. For each type of infection, there can also be a variety of species that

may be causing the disease. Thus, we will only have a general discussion on this group of

diseases.

Ringworm and Related Dermatophytes

Ringworm usually occurs on the exposed parts of the body, forming circular growths that may

appear darker or lighter than the normal skin color, with symptoms that include skin lesion, rash

and itching of the infected area. Ringworm infections are common where conditions are

unsanitary and crowded with people and has been known since early historical time. There are

indications that ringworm was more prevalent in the recent past than now because of

improvements in sanitary conditions and health habits. The Greeks called it Herpes (=circular or

ring form) and the Romans associated the disease with the larval stage of Tinea, the genus for

clothes moth. The two names were eventually combined to "ringworm". Although the actual

cause of ringworm was not known until the early 1800s, the practice of segregating infected

individuals to prevent spread of the disease indicated that there was knowledge that this disease

was contagious and prevalent, and could be passed from person to person was known prior to the

cause of infection.

It was Gruby that isolated and described one of the ringworm fungi, Trichophyton, meaning

"thread plant", and through inoculation on healthy parts of the scalp, was able to reproduce the

disease. He also carried out the same experiment with several other human pathogenic fungi and

inoculated himself with the pathogen, as well as others. Although this was a great

accomplishment, Gruby also had a great deal of luck since, at the time, isolation of specific fungi

was not common practice, and this was also 30 years prior to the development of techniques to

grow fungi and bacteria in pure culture.

According to Ainsworth, more than 350 species of dermatophytes have been proposed and given

approximately 1,000 names, which has caused some confusion in medical mycology. The

proliferation in names have come about because different researchers have worked with the same

species of a pathogen, in a different place and time, and each were familiar with that particular

isolate of that particular species of fungus and probably not too familiar with that isolate. They

grew it in culture briefly and published on it. Thus, each newly isolated dermatophytic fungus

was given a name, sometimes according to the symptoms with which it was associated or

according to the part of the body affected, i.e. top of the head, neck, face, hand, arm, leg and

foot, or even the geographical region, or sometimes just for the sake of publication (due to the

competitiveness of medical schools) . This led to a great deal of confusion in the understanding

of mycoses.

Although the first species were described in the 1840s, they were little studied until the 1940s,

when the United States military personnel, while fighting in the South Pacific, during WWII,

contracted ringworm and other fungi in the humid tropics (an example of advancement of

knowledge due to driven research). This led to an intensive study, by the government of such

fungi with many species being reduced to synonyms. For example, 172 species were reduced to

Candida albicans.

Epidemiology of Ringworm

Fungi that cause ringworm are widespread, geographically, and usually not of major concern,

other than as cosmetic problems. However, cases in which these diseases cause extreme

disfigurements and infections are known to occur, but are rare outside of the tropics, and are

believed to be due to poor diet and unsanitary condition (Christensen, 1965). At one time

ringworm was a common disease, particularly of children of poorer classes. The inferences

usually is that this was mainly a matter of such children being exposed to less soap and water

than were children of the well-to-do. It is probable that deficiency in diet may also have made

them more susceptible. There have been epidemics of ringworm that have developed in many

cities in the United States. Several species of fungi that cause ringworm are common on adults,

and it seems highly probable that some of them are regularly present without causing any

obvious symptoms. Species that cause ringworm belong to the genera Trichophyton and

Microsporum. These genera of fungi are somewhat unusual in that they produce asexual spores,

but not sexual spores or at least produce them so infrequently that they have not been observed.

Species of fungi causing ringworm can be ecologically divided into three groups:

1. Zoophilic or "animal loving." Species infect animals primarily, e.g. cats, dogs, horses,

cows, poultry, but can readily be transmitted to people. This is probably the most

common source of ringworm in people, and is usually caused by Microsporum canis, a

species usually found on cats and dogs. Animals that are carriers of ringworm do not

necessarily show outward signs of the disease. Symptomless animals and probably people

as well are carriers of these diseases. The infections are spread mainly by spores, but

mycelial fragment in skin and hair can presumably also occur. Spores are very long lived

and can remain alive for years in blankets, in clothing, bedding, combs and other

grooming tools.

2. Anthropophilic or "man loving." Species infect people and cannot be transferred to

animals.

3. Geophilic or "earth loving." Species occur naturally in soil, presumably as a saprobe, but

is capable of infecting animals and people. Another words these are facultative parasites!

There must be great differences among individuals in susceptibility to infection of these

ringworm fungi as well as great differences in susceptibility of an individuals at different times.

There are many questions that remain unanswered concerning this species causing the various

forms of ringworm.

Ringworm infections are conveniently divided into categories, based on the part of the body that

was infected:

Tinea capitis: Ringworm of the scalp, eyebrow and lashes.

Tinea corporis: Ringworm of the body.

Tinea cruris: Ringworm of the groin, perineum and perianal region. Infections are

commonly referred to as "jock itch".

Tinea unguium: Ringworm of the nail.

Tinea barbae: Ringworm of the beard.

Tinea pedis: Ringworm of the feet. Infections are commonly referred to as athlete's

foot.

Tinea manuum: Ringworm of the hand.

Left Image: Example of Tinea capitis. Middle Image: Example of Tinea corporis. Right Image:

Example of Tinea pedis (Athlete's Foot). All images courtesy of Dr. Glenn Bulmer, from

http://www.medicalmycology.net.

Note that the various "Tinea" names given to the various forms of ringworms do not constitute

species names. A summary of the above ringworm diseases, based on anatomical locations can

be found on the Medline Plus Health Information. There is also discussion on treatment for the

various types of ringworms that have been omitted on this web page. Warning, this site has

very explicit graphics of these diseases!

Presumably infection is spread mainly by air-borne spores which is why veterinarians do not

want ring-worm infected animals to remain in their clinics or hospitals. If this is the case, all of

us at one time must be exposed to infections by various ringworm fungi. Why is it then that few

of us become infected? Why is infection usually localized, e.g. ringworm of the scalp only

occurs in part while most areas are not affected? Surely, there are enough spores produced that

the entire scalp will be infected. Sometimes one person in a family, or animal in a herd, will get

ringworm and it will not spread to others, whereas other times it is highly contagious. There is a

great deal to be learned about ringworm.

An interesting disease that is not one of the ringworms is piedra. This is a disease of the hair

where mycelium grows along the shaft of the hair and often fuses clumps of hair together.

Usually occurs in unsanitary conditions, in tropical countries. To treat piedra the infected hair is

cut or shaved and a topical azole cream, salycylic acid or 2% formaldehyde is applied to the

affected area.

Systemic or Deep-Seated Mycoses

There are a dozen or more species of fungi causing various systemic or deep-seated mycoses in

man and animals. We will discuss several of the more prevalent species or because of some

interesting aspect of the fungus or disease.

Coccidioides immitis, the cause of Coccidioidomycosis (Valley Fever)

This species is endemic to the southwest, in the United States (California, eastward through

Arizona, New Mexico, and western half of Texas), Northern Mexico and some areas of Central

and South America. In the United States, it is most commonly recorded from Kern County, in the

San Joaquin Valley of California. Infection may occur following travel to one of the endemic

areas. The first case of coccidioidomycosis was described in Argentina shortly before 1890; the

patient suffered for seven years before finally dying and by 1915, there were 40 known cases of

this disease, which was thought to be a rare and universally fatal. However, by this time it was

already known that there was a disease called Valley Fever, which was not associated, at that

time, with C. immitis. It would not be until Dickson (1937) that it was realized that Valley Fever

was just a milder form of coccidioidomycosis. Dickson & Gifford (1938) carrying out

ccoocccciiddiiooiiddiinn skin test of long time residents of Kern County demonstrated that 50-70% have, at

some time been infected by this fungus. The test is like a tuberculosis (TB) test where substances

called antigens that are associated with the disease are injected just below the skin, of your

forearm, and the results read 24 to 48 hours later. If an infection of C. immitis has occurred,

antibodies will be produced by the body that will react with the antigen that has been injected,

causing a large red swelling in the area of the injection.

Coccidioides immitis is contracted by inhalation of spores and primarily causes a respiratory

disease in animals and people, but from the lungs it may spread throughout the body by way of

the bloodstream and cause pathologic changes - skin lesions of one sort or another - in just about

all tissues in all parts of the body. In the usual course of events, infection results in a more or less

acute but benign and self-limiting respiratory disease, but once the patient recovers from this,

they are likely to be permanently immune from further infection. Fiese (1958), an authority on

this disease, says that about 60% of those infected have few or no symptoms, and 40% have

symptoms of varying degrees of severity; chills, fever, chest pains, coughing, lassitude -

symptoms typical of a dozen other infections as well. These symptoms develop ten to fourteen

days after infection, and may persist for some time, but eventually, in most cases, the

immunological processes of the body take over and rids it of infection, although lesions and scars

in the lungs may remain. In a relatively few cases (1 in 500) the fungus is disseminated from the

lungs to other parts of the body, and this secondary stage may result in severe lesions in the skin,

bones, and internal organs and the victim will have massive external and internal lesions and

abscesses. If this stage is reached, it is unlikely that the victim will recover, death will occur

within weeks or after a long and lingering illness. Sometime the disease proceeds to a fairly

advanced stage and then remains static for years, and it may regress and later reappear.

Amphotericin B is the drug of choice to treat this disease.

Left Image: Positive reaction to coccidioidin skin test. Middle Image: Skin lesions from C.

immitis infection, from http://drugster.info/img/ail/1899_1911_2.jpg. Right Image: Skin lesion

from C. immitis infection on face, courtesy of Glenn Bulmer.

Histoplasma capsulatum and Histoplasmosis

Histoplasmosis occurs in people and dogs, rarely has it occurred in other domestic or wild

animals. Infection occurs through inhalation of spores from this fungus. The history of this

disease is similar to that of coccidiomycosis. The first three cases of histoplasmosis was

described in the Panama Canal Zone in 1905 and 1906. The patients died of massive infections,

and in postmortem examination of diseased tissues, the disease was thought to have been caused

by a protozoan (Darling, 1906). Thus, the name H. capsulatum, which refers to what was

believed to be an encapsulated plasmodium found during the autopsy. The first case occurring in

the United States was recorded in 1926 and by 1934 only six cases had been described in

Panama and the United States, all postmortem.

Until 1940, Histoplasmosis was thought to be a rare and almost invariably fatal disease, and little

attention was paid to it. However, in 1940, many men who were given chest x-rays as part of

their physical examination to determine their fitness for military service, were found to have

calcified pulmonary lesions indicative of healed-over infections, which is normally a positive test

for tuberculosis. The incidence of these lesions were especially high in men from the Mississippi

and Ohio River valleys; few of these men tested positive for tuberculin test and so it was unlikely

that these lesions were due to tuberculosis infections. In 1945, HHiiss ttooppllaassmmiinn sskkiinn tteess tt revealed

that a large number of people in some areas of the United States tested positive for

Histoplasmosis, but appeared to be perfectly healthy; at some time in the past they had been

infected with Histoplasma capsulatum (Christie & Peterson, 1945). It was estimated that as

many as 20% of the population of the United States are or have been infected by this fungus. The

great majority of these either have no symptoms at all or suffer only miscellaneous aches and

pains, with a light cough, perhaps some dysentery, very much like symptoms of

coccidioidomycosis, flu, and various bacterial infections. The symptoms soon disappear and the

individual is then highly resistant or immune from further infection by this fungus.

However, again, in a small percentage of cases the fungus spreads, by way of the blood stream,

from the source of the original infection in the lungs throughout the body, and this may result in

massive infection that is usually rapid and fatal. Thus, the disease is very widespread, but until

1940, it was thought to be a rare, but fatal disease which was usually not diagnosed until an

autopsy was carried out and may not have been recognized even then. More cases probably

occurred, but because few pathologists were trained to recognize fungal diseases. Medical

mycology was still a little studied area at this time. As was the case in coccidioidomycosis, once

the disease has been disseminated from the lungs to the rest of the body, it is likely to be fatal

and nothing can be done.

Although there is a high incidence of this disease, it is not communicated from animal to animal

or person to person or even animal to people. It seems likely that the infection source is from the

soil where it has been demonstrated to exist as a saprobe. However, it apparently does not

sporulate in soil, but rather only in droppings of birds and bats. The fungus grows there and

presumably sporulates on the droppings. This is the reason that public parks throughout the

country do not allow people using the park to feed the birds. Large number of birds feeding in a

given area, where there are often a lot of people, would present an environment where there is

greater probability that someone may catch this disease.

Although this disease is little known, several years ago, on May 25, 1997, Bob Dylan was

hospitalized, with histoplasmosis, although his life was threatened, he apparently was never in

danger of dying of this disease. However, the disease became far better known after he

contracted it. I was still able to find a brief mention of this news story in the archives of the Los

Angeles Times. If you wish to read this article, click here.

Left Image: Histoplasmosis infection of gum, from

http://www.doctoribolit.ru/images/Histoplasmosis/Histoplasmosis04.gif. Right Image: Skin

lesion of upper lip due to histoplasmosis infection, from Centers for Disease Control and

Prevention's Public Health Image Library #6840.

Blastomyces and Blastomycosis

There are two species of this genus, Blastomyces dermatitidis and B. brasiliensis that occur in

North America and South America, respectively. These species occur naturally in soil, especially

soil in animal habitats. It is apparently widespread in Kentucky and Arkansas where infection in

dogs is common. Infection is rare in other animals, but have been recorded in cats, one horse and

one sea lion.

Infection apparently comes from spores or mycelium in the soil and any part of the body may be

invaded. Infections usually are first detected as skin lesions; the lesions may remain localized or

may gradually enlarge. In some case the fungus can spread throughout the whole body, resulting

in extensive ulceration. Males are infected more frequently than female - in some studies the

ratio is 15:1. There is no effective treatment.

Intermediate Infections

These are diseases that are intermediate between the first two categories. These fungal infections

may extend to a considerable depth within the tissue, but unlike the systemic diseases will not be

distributed to the rest of the body. One of the most common intermediate infection is Candida

albicans.

Candida albicans and Candidiasis

Candida albicans is a dimorphic fungus. That is, it grows as both mycelium and yeasts. This is

one reason why there were so many names given to this fungus. This fungus normally occurs in

the mouth, digestive tract, and vagina of perfectly healthy people, but under some circumstances,

and for reasons unknown, it may cause severe and even fatal infections, with lesions and

eruptions of the skin, nails, mouth, bronchial tubes and lungs. There are suggestions that there

are special strains of this species that are pathogenic. This is suggested by the fact that this

disease can be contagious and epidemics have occurred. Predisposition may also play a role in

infection. Oral infections known as thrush is relatively common. Infections can occur on various

parts of the body.

Candidiasis infections on various parts of body: Left Image: On tongue, commonly referred to as

Thrush. Middle Image: On neck. Right Image: Is a case where it is fatal. Lack of T-Cells allowed

infection to occur on many parts of body. Images courtesy of Glenn Bulmer, from

http://www.medicalmycology.net.

Chromoblastomycosis

Disease is mostly tropical to subtropical, but was first reported from Boston in 1915 and may be

caused by several species of fungi. Species causing this disease are mostly soil inhabiting or on

decaying vegetation and typically enter the foot or lower part of the leg through wounds from

walking bare-footed. Early treatment involves excision of infected area or cryosurgery. Chemical

treatments vary in their success of controlling this disease.

Left Image: Fonsecae pedrosoi infection of left leg. Right Image: Same leg after daily treatment

with Itraconazole. Images courtesy of Glenn Bulmer, from http://www.medicalmycology.net.

Aspergillus fumigatus and Aspergillosis

Aspergillus fumigatus is a species complex rather than a single species. It is actually composed

of ten species. These species are commonly found in decaying vegetation, especially when the

latter is undergoing microbiological heating, because this complex is thermophilic, adapted to

growing at high temperatures 50 - 55ºC (120 -130ºF).

Aspergillus fumigatus sometimes parasitizes animals, especially birds, infecting mainly lungs

and causing heavy mortality - up to 50% in young turkeys and up to 90% in young chicks. Heavy

losses have also been reported in herring gulls, ostriches and diving ducks in the wild and in

penguins in zoos. The fungus can also invade the embryos of eggs in incubators, and probably

does the same in eggs in nest in the wild. It also invade the uterus of pregnant cattle and grows

through the placenta into the fetus, which then dies and is aborted. It has been estimated that

64% of bovine abortion investigated were due to infection of A. fumigatus.

In people, the disease can lead to a chronic lung infection which is apparently very contagious.

The fungus is thought to cause death, but that is not certain. In patients that have died and A.

fumigatus has been isolated, many have also had underlying disease that possibly lowered their

resistance to the fungus. However, it is also possible that the fungus had lowered their resistance

to the other infective agents. It is difficult to know what came first.

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