I&I: Into to Mycology

What is Mycology?

The study of Fungi

What are the two different types of Fungi?

Pathogenic

Non-Pathogenic Fungi

What are some general characteristics of Fungi?

Eukaryotic, non-motile and heterotrophic organisms

Lack chlorophyll and hence cannot perform photosynthesis

Cell walls are made of Chitin

They are resistant to antibacterial drugs

What are the 3 morphological classification of fungi?

Yeast

Mold

Dimorphic Fungi

What are characteristics of Yeast?

Unicellular

Grow on solid media

Some genera produce mucoid colonies

Few produce pigment

What is it called when yeast cells chain together and resembling true hyphae?

Pseudohyphae

What are diseases that are associated with Candida?

Thrush

Mycotic stomatitis

genital candidiasis

Enteritis

Crop mycosis

Metritis

Vaginitis

What disease cause otitis externa in dogs when too many are present?

M. Pachydermatis

What disease causes chronic dermatitis such as pruritis, alopecia, erythema?

M. Pachydermatis

What is the shape of Malassezia yeast?

Bottle shaped or foot print shaped

What are some characteristics of mold?

Grow on solid medium

Look fluffy or cottony

Produce pigment

Hyphae and conidia

What are the two typed of morphology of molds?

Hyphae

Mycelium

What type of morphology of mold is branched tubular structure?

Hyphae

What thype of morphology of mold is a web or mat-like structure?

Mycelium

What disease does Aspergillus Funigatus cause in chicks?

Brooder pneumonia

What disease does Aspergillus Funigatus cause in Cattle?

Mycotic abortions

What disease does Aspergillus Funigatus cause in Horses?

Guttural pouch mycosis and Keratitis

What disease does Aspergillus Funigatus cause in Dogs?

Nasal apergillosis

What does Brooder pneumonia post-mortem lesion look like?

Yellowish or whitish, caseous nodules on lungs

Why is Dimorphic Fungi special?

They act like yeast at 37 degrees C (in animal body) but will act like a mold at temps at 25 degree C

Spores from what may cause infection via respiratory tract?

Mycelia

What is the classification of Ringworm fungi?

Yeast (dermatomycoses)

What is the classification of Candida, Malassezia?

Yeast and yeast-like fungi

What is the classification of fungi that involve keratinized tissue of hair/nails or corneum of skin?

Superficial

What is the classification of Sporotrichosis and mycetoma or fungi that involve lymphatic vessels?

Subcutaneous

What is the classification of fungi that may involve many organs?

Systemic mycoses

What are three types of transmission of mycotic infection?

Direct contact

Inhalation

Ingestion (Mycotoxin)

What are characteristics of the pathogenesis of fungi?

Low morbidity/contagiousness

Chronic nature

Ability to adhere to host cells

Production of capsules

Ability to damage host by secreting enzymes such as keratinase

Ability to secrete mycotoxins

What predisposing factors of fungi?

Exposure to fungal spores

Adherence to moist skin

Prolonged antibacterial therapy

Surgical procedure

lowered host resistance

What is necessary to prevent bacterial contanimation when collecting and transporting a specimen?

Sterial containers

What temp should you transport a speciman?

Room temp

What are the anatomic sites that are appropriate for culture?

Tissue biosies

Sputum

Cantaneous-sking scraping

Where should samples be taken from the infection site?

periphery

What should you do first to diagnosis fungal in a clinical sense?

Signs and wood lamp test

What laboratory methods should you use to diagnose a fungle infection?

Direct: wer mount with 10% KOH

How does KOH effect fungal cells?

KOH dissolve keratin cellular materials and release of fungal hayphae and yeast cells

What is the most used diagnostic medium and will give you a diagnostic answer for fungal infections?

Culture (Sabouraud Dextrose Agar)

What are the requirements for Sabouraud dextrose agar?

Temp 25-37C

At least 4 weeks

Positive cultures (7-10 days)

How long does it take for Candida and Aspergillus to show up on a culture?

24 to 72 hrs

What is an infection of superficial, keratinized tissues called?

Dermatophytosis

What species is Dermatophytosis found?

Humans

Animals

Soil

What are the two types of Dermatophytes?

Microsporun

Trichphyton

What skin condition is associated with dermatophyte infection?

Alopecia

How do you collect a sample to test for Dermatophytes?

Pluck hair from the periphery of the lesion

How do you confirm the fungal infection even though there is absence of fungal element in both the wood lamp and KOH test?

Culture method to confirm

A 2 year old dog develops itchy skin and loss of hair in various body parts. What is the most reliable lab methods to confirm this skin infection?

KOH and Fungal Culture Medium

What are examples of Dimorphic Fungi?

Crytococcosis

Blastomycosis

Histoplasmosis

Coccidioidomycosis

Zygomycosis

What disease remains in yeast form in both 25 and 37C, bird dropping a common source of infection, and is a sporadic disease in cats and dogs?

Crytococcus Neformans

What is the process of Crytococcus neoformans and how it disrupts the host?

Airborne infection

forms capsules

host cell membrane disruption

nasal granulomas

Paranasal sinuses

hematogenous dissemination

What are the clinical signs of crytococcus neoformans?

Sneezing, snuffing, mucopurulent/hemorrhagic nasal discharge

What are the three forms of crytococcosis in cats?

Cutaneous

Systemic

CNS

What type of crytococcosis in cats is a single or multiple non-painful, non-itchy nodules on or below their skin?

Cutaneous Crytococcosis

What type of feline crytococcosis is infection spreads through the bloodstream and multi-organ system disease?

Systemic

What type of Feline Cryptococcosis causes sudden blindness, seizures, behavioral changes?

CNS

What are three ways to diagnose Crytococcosis?

Wet mounts

Culture

Agglutination test

What main species are affected my blastomycosis?

Dog

Human

Where does Blastomycosis occur?

USA

What is the process infection of Blastomycosis?

Aerosol inhalation

Granulomatous lesions in lungs

respiratory distress

What is the source of Histoplasmosis?

Soil enriched with bat or bird excreta

Where is Histoplasmosis found?

USA

What species is most affected by histoplasmosis?

Dogs and cats

What is the process of infection of Histoplasmosis?

Infection via inhalation

Granulomatous lesion/nodules in lungs

Intestine may also be affected

What disease has the nickname valley fever?

Coccidiodomycosis

Where is Coccidiodomycosis found?

Southern USA

South America

What species is most affected by coccidioidomycosis?

Dogs

What is the mode of transmission of coccidioidomycosis?

inhaling infective arthrospores

What disease has the nickname Rose Gardeners Disease?

Sporotrichosis

What type of fungus if Sporotrichosis?

Soil-borne, dimorphic fungus

What species are most affected by Sporotrichosis?

Horse, mules, rarely dogs cats, humans

How is sporotrichosis spread?

Infected via skin wound then spread by lymphatic spread

What is the consequences of ingesting frains or forage containing mycotoxins?

Mycotoxicosis

What are the two types of presentations of mycotoxicosis?

Non-contagious, sporadic

Acute or chronic poisoning

What is the mode of transmission of Mycotoxicosis?

Ingestion

Direct contact

What are the signs of mycotoxicosis?

Decreased feed cinsumption or feed refusal

How do you demonstrate good agricultural practices for mycotoxins?

Testing for toxins

Sufficient drying of crops after harvest and pasture control

What are signs of pithomyces chartarum?

Extensive skin sloughing

Photosensitization on sheep

What fungal toxic substance/metabolites cause mycotoxicosis?

Toxins formed by fungi growing in feed/food