LEC 5 - Systemic Mycoses Flashcards
What do all biphasic/dimorphic soil fungi cause?
Pulmonary disease
which can spread to other areas
What are the three/four examples of edemic fungi?
Coccidioides immitis + posadasii
Histoplasma capsulatum
Blastomyces dermatitidis
Define: Edemic pathogen
Restricted to specific geographical region
What are other names for coccidiodes?
Coccidioidomycosis
San Joaquin Valley Fever
Cocci
Where is C. Posadasii located?
Argenitina
Where is C. Immitis located?
California
Morphology of Coccidioides
Biphasic
Non-Dimorphic = Spherule + Mold
NO YEAST FORM
What does coccidioides look like in tissue?
Nonbudding spherules
Describe: Spherules
Rich in lipids
Surrounds by giant cell
What is another name for Spherules?
Endosporulating spherule
What do spherules do?
Release endospores
These will then form new spherules
What tissues are susceptible to spherules?
Lungs Skin Cardiac Pericardium Bones CNS
How is coccidiodies found in nature?
Hyphae
Alternate between barrel-shapped arthrospores/empty
– and –
Disjunctor cells
How long does it take Coccidioides to become mold in culture?
1 to 2 wks
What type of agar is used for Coccidioides growth?
Sabouraud agar
Define: Coccidioidin
Hyphal antigen
Used for immunodiagosis
What animal is most affected by coccidioides?
Dogs
What type of infection do pigs and cattle get?
Subclincal or inapparent
What is the most common infection type with coccidioides?
Pulmonary
What form of coccidioides is inhaled?
Arthroconidia
What is the incubation period of coccidioides?
7 to 20 days
What happens when coccidioides arthroconidia are inhaled?
Spherules with endospores form in lungs (and elsewhere)
What is the primary CONDITION seen in humans with coccidioides ?
Pneumonia or influenza like symptoms
Most are benign or inapparent
Self-limitign most of the time
Where does the agressive form of coccidioides tend to spread?
Lungs + Skin + Bones + Joints + CNS
What ethnicities tend to be most affected by coccidioides ?
Asians
Blacks
Hispanics
What clinical signs are seen in dogs with a coccidioides infection?
Fever Lethargy Inappentence Lameness Coughing Dyspnea Bone swelling Wt. Loss
Define: erythema Nodosum
Tender red cutaneous nodules in shin region
Delayer hypersensitivity to fungal antigens
What is Erythema Nodosum a good indicator of? Why?
Good prognosis
Cell-mediated immunity is functional
Soil dwelling structures of coccidioides
Arthroconidia
Hyphae
What are ways to diagnose an animal with coccidioides?
Septum/Bronchoalveolar lavage - Sperules
PAS - Histopathilogical exam of affected tissue
Histological description of coccidioides
Giant cells w/ spherules
What blood work can be done to test for coccidioides?
IgG + IgM with Ab’s to coccidiodin
BSL: coccidioides
BSL3
DOC: coccidioides
Triazoles (Fluconazole + Itraconazole)
Before lab confirmation
How long is therapy for coccidioides?
~ 1 year for dogs
Control: coccidioides
Reduce dust by water dirt + planting vegetation + paving road
Infection allows for immunity
What is the telemorph of Histoplasma capsulatum called?
Ajellomyces capsulatus
What does H. Capsulatum produce disease in?
Dogs + Cats + Humans
How many variants of H. Capsulatum are there?
3
Morphology: H. Capsulatum
Dimorphic
Uninucleated budding cells
Mold = micro/macroconidia
Tuberculate macroconidium
What cell types do H. Capsulatum like to reside in?
Macrophages + PMNs
What type of parasite is H. Capsulatum?
Facultative intracellular parasite
What does the mold of H. Capsulatum look like in culture?
Cottony mold
How long does it take H. Capsulatum to grow?
12 weeks
How is H. Capsulatum inhaled?
Microcondidia
What happens to the microcondidia once it is inhaled?
Becomes yeast cells
Clinical signs in humans: H. Capsulatum
Influenza like symptoms
Non-productive cough + Fever
Self-limiting
Why might dissemiated disease due to H. Capsulatum happen in dogs and cats?
Impaired cell-mediated immunity
What can the body do to H. Capsulatum yeast once in the lungs?
Phagocytosed by alveolar macrophages
= transported deeper into the body
HUMANS: What types of lesions occur with H. Capsulatum? Where?
Granulomatous foci in lungs + spleen
DOGS/CATS: What types of lesions occur with H. Capsulatum? Where?
Granulmatous lesions in lungs sometimes
What can a H. Capsulatum progress to that can lead to death in dogs?
Diesseminated histoplasmosis
How does disseminated histoplasmosis present in dogs?
Ulcerative intestinal lesions = diarrhea
How does disseminated histoplasmosis present in horses?
Lymphocutaneous lesions
What treatment is recommended in horses with disseminated histoplasmosis?
Amphotericin B
Virulence Factors: H. Capsulatum
Urease
Ammonia
Bicarbonate
What state of H. Capsulatum produces the virulence factors?
Yeast
What do the virulence factors produced by H. Capsulatum yeast cause?
Raise pH
Blunt/Eliminate killing action of phagolysosome
How does host resistance occur in regards to H. Capsulatum?
PMN expresses fungistatic activity + functional T cell-mediated immunity critical
What manifests 100% of the time in humans with disseminated disease from H. Capsulatum?
Fever
Where is H. Capsulatum most commonly found?
Eastern US
Transmission: H. Capsulatum
Aerosol of microconidia
What type of soil conditions does H. Capsulatum prefer?
Bat guano
– or –
Bird droppings
How can H. Capsulatum be ID’ed?
Direct microscopic exam
Culture
Histoplasmin
Culture: H. Capsulatum
Tuberculate macrocondia in culture
What do you get a culture for H. Capsulatum from?
Sputum
Urine
Lesions
Buffy coat
Stain: H. Capsulatum
Giemsa-stained smears of marrow or blood
Therapy: H. Capsulatum
Itraconazole + Amphotericin B
most patients need no treatment
Sexual stage: Blastomyces Dermatitidis
Ajellomyces dermatitidis
Major clinical sign: B. Dermatitidis
Chronic granulomatous disease
Morphology: B. Dermatitidis
Thermally dipmorphic
Appearance in tissue/exudate: B. Dermatitidis
Multinucleate, broad-based budding cell
Appearance in culture: B. Dermatitidis
Hyphae bear conidia + chlamydospores
Infection phase: B. Dermatitidis
microcondidia or mycelial fragments from soil
Animals B. Dermatitidis produces disease in
Humans + Dogs
Clinical symptoms: B. Dermatitidis
Pulmonary disease
Where can B. Dermatitidis deseminate to?
skin + eyes + bone
Define: BAD1
B. Dermatitidis
Promotes adhesion to respiratory epithelium
Epidemiology: B. Dermatitidis
Ohio + Mississippi river
Mexico
Central america
Some of Africa
What is a sign disseminated disease has occurred with B. Dermatitidis ?
Metastatic skin lesions
Culture: B. Dermatitidis
Sabouraud agar