MYCOLOGY & VIROLOGY

Mycolology

Study of fungi

-May be unicellular or multicellular

-Eukaryotic

-Achlorophyllus

General Characteristics (Fungi)

Multicellular

It means fungi are different in cell structure

Unicellular

It means fungi has the Same structure

Eukaryotic

True cells; has membrane-bound cells; has nucleus

Achlorophyllus

No chlorophyl/color

Sexual spores

Requires male and female to reproduce

Asexual spores

Binary fission; where a single cell divides into two identical daughter cells.

Spores

Reproduction in fungi is accomplished through the formation of_____.

Yeast, Mold, Dimorphic

3 morphologic types of fungi

Yeast

Are unicellular; reproduced through budding(asexual); produced in heat.

Mold

Multicellular; filamentous form consisting of threadlike hyphae; produced in cold

Dimorphic fungi

Consist of both yeast and mold

-Diseases are primarily a result of the host's immune reaction.

-A few species are able to reproduce toxins (myotoxins)- released by fungi

Fungi Pathogenicity

1. Cutaneous Mycoses

   -Superficial Mycoses

   -Dermatophytoses (ringworms)

2. Subcutaneous Mycoses

3. Deep seated/Systematic/Endemic

4. Opportunistic mycoses

Classification of Fungi according to type of infection

Cutaneous mycoses

-Confined in nails, hair, skin; most common type of fungal infection

Subcutaneous mycoses

Affects the muscles, connectivetissues, and sometimes bones.

Deep seated/ systematic mycoses

Affects deep tissue organs; affects those with low immunity

Endemic mycoses

Also affects healthy individuals

Opportunistic mycoses

Cause infection if weak immune system.

(Immunodeficient, immunosupressed, with chronic diseases)

Superficial mycoses

Not recognized by our immune system; little tissue damage

Dermatophytoses (ringworms)

Recognized. Affects keratenized layer of skin, hair, nails. Ex: Athlete's foot

KOH mount, culture and susceptibility

Laboratory diagnosis for fungi

-The most common method of direct microscopic exam in mycology

-Often used to confirm a diagnosis of cutaneous mycoses

What is KOH mount

Adding a 10% KOH solution to skin, scrappings preferably from the sides of the wound (fresh infection) and viewed under the microscope.

How is KOH mount performed

Culture and susceptibility

-Specimens are inoculated into artificial media and allowed to grow

-Isolates are ifentified through a combination of microscopy and biochemical tests

-Isolates may also be tested against antifungal drugs for susceptibility and resistance

It helps physicians in prescribing the correct type of dosage

Why is culture and susceptibility important

Virology

Study of virus

-smallest infectious agents

-obligate intracellular parasites

General Characteristics (virus)

Genome, capsid, envelope, peplomers/spikes

General structure components of virus

Genome

Contains either DNA or RNA but not both

Capsid

Protein shell that protects the genome

Envelope

Derived from a host cell memebrane; not present all virus

Peplomers/spikes

Used for attaching to the host cell prior to penetration

1. Attachment

2. Penetration

3. Uncoating

4. Eclipse

5. Synthesis

6. Release

Viral infectious cycle

False (not all)

All viral infections lead to the formation of lysogeny

True

Some viral infections lead to lysogeny

True

Different viruses may interact when found infecting the same cell

True

Viral infections may be genetic or non -genetic

-damage or death of host cells

-Changes due to the incorporation of viral genes (e.g. cancer formation)

Virus Pathogenicity

1. Electron microscopy

2. Antibody detection

3. Viral culture and isolation

4. Nucleic acid detection

Laboratory diagnosis for Virus

False (they are grown)

Virus are not grown in cell cultures, embronated eggs, or through animal inoculation

True

Viruses that infects the same cell may interact by exchanging germs or gene products

PRIONS

-Proteinaceous material devoid of nucleic acids

-misfolded protein

-Found in brain tissue

-Agent of transmissible spongiform encephalopathy

-Non immunogenic

-Always fatal

True

With prions, there are no case of remission and recovery at all

False (they are identified through autopsy)

Signs of prions are not identified through AUTOPSY