Cryptococcus, Histoplasmosis, Blastomyces, Coccidioides

Question 1

Common features of Cryptococcus, Histoplasmosis, Blastomyces, Coccidioides

Answer 1

Inhalation of spores transform into yeast or alternative form in lung
Cell mediated immunity is required for protection, if inadequate dissemination throughout body and chronic disease results
Granulomas or pyogranulomas are characteristic lesions
Location and travel history is important for diagnosis
Long term antifungal therapy is needed to treat them all, no vaccines available

Question 2

Cryptococcus Features

Answer 2

Dimorphic, encapsulated yeast, **polysaccharide capsule

Question 3

C. neoformans reservoir

Answer 3

Birds- pigeon guano

Question 4

C. neoformans causes disease in what type of host

Answer 4

Immunocompromised hosts

Question 5

C. neoformans is located where

Answer 5

Worldwide

Question 6

C. neoforma Disease is what in what

Answer 6

Most common systemic fungal disease in cats
Cryptococcosis in cats- a localized infection in upper respiratory tract resulting in lesions which can spread to surrounding areas (eyes and skin- skin lesions common) or through cribiform plate to brain causing cryptococcomas

Question 7

Cryptococcosis diagnosis

Answer 7

Stain sample with India ink and capsule will not uptake the stain- so reverse stain
In histology can stain with mucicarmine to stain capsule rose red
Culture or capsule serotyping- can measure quantitatively using capsule antigen circulating in the blood, any value is significant

Question 8

Cryptococcosis Treatment

Answer 8

Surgically remove granulomas and treat with antifungals, but poor prognosis if in brain
Need to treat for 2 months after titer value is zero

Question 9

Histoplasma capsulatum is found where

Answer 9

Mold form and spores in soil after being excreted from bird and bat feces and yeast forms in vivo, birds are reservoirs
In Mississippi and Ohio river valleys and parts of central and South America

Question 10

Cryptococcus, Histoplasmosis, Blastomyces, Coccidioides Mold forms are

Answer 10

Infectious

Question 11

Histoplasma capsulatum Transmission

Answer 11

Inhaled microclamidia from soil infected with spores/mold from bird/bat droppings get to macrophages in lungs and are phagocytosed, yeast cells develop and kill macrophage and disease can be disseminated from there because macrophage takes it to lymphnodes

Question 12

Histoplasmosis common symptom is

Answer 12

Disease occurs commonly in Dogs, cats, and humans however no overt symptoms
Pneumonia is only in a small percentage of animals (dogs and cats)

Question 13

Disseminated histoplasmosis leads to

Answer 13

Weight loss and diarrhea (in dogs most common)

Question 14

Histoplasmosis diagnosis

Answer 14

Culture and look for dimorphism
Or a cytology looking for yeast in macrophages
Or histopathology of biopsy
Or serology for antigen but is sensitive not specific for histoplasma

Question 15

Histoplasmosis treatment

Answer 15

4-6 months of antifungal therapy only in animals with clinical disease only

Question 16

Blastomyces type of fungus

Answer 16

Dimorphic

Question 17

Blastomyces found where

Answer 17

Moist soil in Midwest and southeast and Mississippi River basin and distribution expanding

Question 18

Blastomyces Transmission

Answer 18

Spores/microconidia are inhaled from moist area and become yeast form and goes to lung and disseminates through blood form there. Most infected dogs live within 400 meters of a lake or river

Question 19

Blastomyces Can be destroyed by

Answer 19

Cell mediated immunity

Question 20

What symptoms can happen from Blastomycosis

Answer 20

Only 5% of dogs develop pneumonia and disseminated disease- usually immunosuppressed
Disseminated disease can cause skin lesions or even ocular disease and bone involvement/ infection

Question 21

Blastomycosis Diagnosis

Answer 21

Cytology/ histopathy to visualize broad-based budding yeast in sample
Or culture on Sabouraud’s agar

Question 22

Blastomycosis treatment

Answer 22

Long term Antifungals for 2-3 months at minimum and recurrence post therapy is common and restrict immunocomprimised dogs from lakes and creeks

Question 23

Coccidiodes species are

Answer 23

Coccidioides immitis and posadasii

Question 24

Coccidiodes species are Found where

Answer 24

In soil as mold form in west..

Question 25

Coccidiodes in soil form

Answer 25

Hyphae fragment to create arthroconidia which go to top of soil and will germinate after rainstorm or dust storms or other forms of soil disruption can make them airborne
Once inhaled can form spherules in host (not a yeast a specific fungal form) with release endospores in animal

Question 26

Coccidiodes Is dimorphic?

Answer 26

Yes but no yeast form- forms spherules and mold

Question 27

Are animals infected with Coccidiodes contagious

Answer 27

No only arthroconidia are infectious

Question 28

Disease from Coccidiodes

Answer 28

Valley fever/ Coccidioidomycosis

Question 29

Symptoms of valley fever

Answer 29

Pneumonia and high fever and cough (granulomas in lung) and dissemination but rare but can cause infection of bone- lameness, limping, arthritis
most infected dogs are asymptomatic

Question 30

Coccidioidomycosis/ valley fever diagnosis

Answer 30

Clinical signs and location, Cytology, histology, and serology but not specific

Question 31

Coccidioidomycosis Culture done?

Answer 31

No it is a select agent and biohazard

Question 32

Coccidioidomycosis Reportable?

Answer 32

Yes

Question 33

Coccidioidomycosis Treatment

Answer 33

Long term antifungal therapy but prognosis for disseminated disease is poor
Be careful in areas it is found during dust storms or construction sites for immunocompromised animals

Question 34

Blastomyces dogs vs. humans

Answer 34

dogs are 10x more susceptible than humans

Question 35

What dimorphic fungus is the most virulent in the US

Answer 35

Coccidioides spp