Unit 4- Systemic Mycoses

Question 1

Infection

Answer 1

By inhalation but noncontagious

Question 2

Dimorphism

Answer 2

Molds in saprophytic phases, coccidioides produces sporangia in tissue, others are budding yeasts

Question 3

Lesions

Answer 3

Granulomatous in lung, systemic dissemination

Question 4

Coccidiomycosis

Answer 4

Desert soil, primary lesions in lungs and secondary in bones, mostly dog, horse, cat, and human

Question 5

Coccidioides Virulence

Answer 5

Adhesins in spherule outer wall glycoprotein, beta glucosidase 2 secreted by endospore, chitinase 1 releases endospores, beta-1 3-glucanosyltransferase gel, serine proteases, urease

Question 6

Coccidioides Immune Response

Answer 6

IgM to Bgl2, TH1 to gel, and TH1 to urease

Question 7

Coccidioides Growth

Answer 7

Simple media, mycelial on SAD or blood agar, gray colonies with aerial mycelium, arthroconidia produced after a few days

Question 8

Coccidiomycosis Pathogenesis

Answer 8

Arthroconidia inhaled and form spherules, spherules release endospores that form new spherules, disseminates from lung to other tissues

Question 9

Coccidiomycosis Diagnosis

Answer 9

Coccidioidin skin test, immunodiffusion, compliment fixation test, latex agglutination

Question 10

Histoplasma capsulatum

Answer 10

Mycelium in saphrophytic phase with septate hyphae and spherical microconidia with tuberculate macroconidia with fingerlike projections, yeast in parasitic phase

Question 11

Histoplasma Virulence

Answer 11

Histoplasmins from mycelium, adhesins to enter cells, calcium protein chelates calcium, H antigen elicits immune response in yeast phase, iron acquisition, M antigen catalase, melanin, phagolysosome acidification

Question 12

Histoplasma Transmission

Answer 12

In soil and bird and bat droppings, inhalation of microconidia or hyphae

Question 13

Histoplasmosis

Answer 13

Primary lesions in lungs and dissemination to other organs

Question 14

Histoplasmosis Diagnosis

Answer 14

Histoplasmin skin test, immunodiffusion, compliment fixation, latex agglutination, immunofluorescence

Question 15

Blastomyces dermatidis

Answer 15

Mold in saprophytic stage producing conidophores, budding yeast in tissue

Question 16

Blastomyces Virulence

Answer 16

Bad1 adhesins prevent ROS and cytokines from phagocytic cells

Question 17

Blastomycosis Pathogenesis

Answer 17

Spores inhaled to alveoli, acute pulmonary phase leads to self limiting control or asexual budding leading to pyogranulomatous inflammation in lungs or lymphatic and hematogenous spread of spores

Question 18

Blastomycosis Diagnosis

Answer 18

SAD agar, intracellular yeast on examination

Question 19

Aspergillus fumigatus

Answer 19

Molds with septate hyphae and characteristic asexual fruiting structures on conidophores

Question 20

Conidiophores

Answer 20

Hyphal branches originating by a foot cell in mycelium and ending in a vesicle, vesicle covered in phialides that form chains of pigmented conidia

Question 21

Aspergillus Virulence

Answer 21

Adhesins, PAMP cell wall triggers toll like receptors on macrophages, elastase, protease, phospholipase, iron acquisition, melanin

Question 22

Aspergillus Growth

Answer 22

Grow on all common lab cultures, grow in environment, soil, vegetation, feed, air, and water

Question 23

Aspergillosis Transmission

Answer 23

Inhalation or ingestion of environmental sources

Question 24

Aspergillus fumigatus Pathogenesis

Answer 24

Inhalation or ingestion, opportunistic pathogen, suppurative exudate in pulmonary infection, mycelial growth into blood vessels, vasculitis, thrombus, systemic dissemination, granuloma in many tissues

Question 25

Aspergillosis Epidemiology

Answer 25

Bovine abortion, coincides with poor husbandry in chickens, stress leads to outbreak, doliocephalic dogs get canine nasal aspergillosis, T-lymphocyte deficiency, antibacterials and steroids in horses predispose

Question 26

Aspergillosus Immunity

Answer 26

Cell mediated immunity important, immune weakness leads to infection

Question 27

Aspergillosis Diagnosis

Answer 27

Hyphae, fruiting heads, and conidia on direct examination, culture, immunodiffusion, ELISA, PCR

Question 28

Pneumocystis carinii

Answer 28

Opportunistic pathogen causing pneumonia in immunocompromised horses and dogs