Aspergillus

Question 1

characteristics

Answer 1

-rapidly growing septate fungi
-pigmented colonies= blue grey
-conidiophores are unbranched. Helpful in differentiating from Penicillium
-very small spores 2-3micrometers. Can reach ends of bronchial tree

Question 2

Natural host or habitat

Answer 2

-ubiquitous in soil and decomposing matter
-Aspergillus fumigatus- found in overheated spoiled hay
-Aspergillus infections are uncommon and usually sporadic
-often in respiratory tract= infection, and hypersensitivity but more evidence of this in people)

Question 3

Aspergillus in birds

Answer 3

1. Brooder pneumonia in young chickens
2. Aspergillosis in mature birds

**penguins are particularly susceptible

Question 4

Aspergillus in young birds

Answer 4

Causes brooder pneumonia
-in young chicks exposed to large umbers of spores
-nodules in lungs and air sacs
-associated with dirty environments/ high load of spores

Question 5

Aspergillous in mature birds

Answer 5

-inhalation of spore laden dust
-clinical signs include dyspnoea and emaciation
-nodules seen in lungs

Question 6

Guttural pouch mycosis

Answer 6

-unknown predisposition. Caused by Aspergillus fumigatus

-diagnose through clinical signs and endoscopic examination

Question 7

Clinical signs of Guttural pouch mycosis

Answer 7

-often unilateral
-epistaxis, dysphagia, laryngeal hemiplegia, facial nerve dysfunction
-horner’s syndrome
-afebrile
-fungus invades neuro/vascular structures

Question 8

Treatment of Guttural pouch mycosis

Answer 8

-case fatality rate= 1/3; prognosis poor without treatment

Treat:
-debridement of lesions
-topical antimicrobial therapy (enliconazole, miconazole)
-iatrogenic thrombosis and embolization of carotid = prevents bleeding following debridement and takes away blood supply to fungus
-parenteral antifungals= questionable use

No prevention or control

Question 9

Mycotic abortions in cattle

Answer 9

-sporadic disease
-typically occurs 6-8mths into pregnancy; will reach placenta through blood
-associated with poor quality feeds

Question 10

Mycotic abortions signs on placenta

Answer 10

• reach placenta through blood
  -see ringworm like lesions on abortuses
  -thickened placenta with necrotic co
  -no sign systemically tyledons

Question 11

Nasal aspergillosis in dogs

Answer 11

-Aspergillus fumigatus which produces osteolytic toxins causing destruction of turbinates and erosion of cribriform plate

-diagnosis through physical exam and nasal workup (can include rhinoscopy)

Question 12

Clinical signs of nasal aspergillosis in dogs

Answer 12

-mucopurulent nasal discharge
-sneezing
-nasal discomfort (pawing at nose)
-other nasal disease signs (stridor or stertor)

Question 13

Treatment for aspergillosis in dogs

Answer 13

1. Treatment
   -systemic therapy has poor success rate 40-60%
   -azole antifungals
   -hepatic toxicity is an issue
   -debride fungal plaques
2. Topical antifungal therapy
   -enilconazole or clotrimazole (1% solution infused in catheters into nasal for 1 hr)
3. Trephination of sinus
   -fill with clotrimazole cream and close hole with bone wax
4. Check cribriform! Needs to be intact. Don’t want medications to reach brain

Question 14

Aspergillus in humans

Answer 14

-A. fumigatus or flavus
-commonly affect respiratory system

Question 15

3 possibilities for Aspergillus in humans

Answer 15

1. Allergic bronchopulmonary aspergillosis
2. Aspergilloma
3. Invasive aspergillosis

Question 16

Allergic bronchopulmonary aspergillosis

Answer 16

-similar signs to asthma

Question 17

Aspergilloma in people

Answer 17

-cough, hemoptysis, shortness of breath

-involves a fungus ball, and matt of hyphae which develop secondary to other conditions
-often in lungs

Question 18

Invasive aspergillosis

Answer 18

-fever, chest pain,

-very high mortality rates
-94% mortality in bone marrow transplant patients

Question 19

Swimmers ear

Answer 19

-infection of otitis externa by aspergillus

-itching, pain, scaling

Question 20

Sample collection and handling

Answer 20

1. tissue biopsies
   -lung, nodules, nasal
2. Abortuses
   -placental tissues, fetal abosmasal contents
3. milk
4. scrapings
5. fungal plaques

**no freeezing

Question 21

Lab ID

Answer 21

-direct microscopy (KOH preps of tissue)

-Culture (sabouraud dextrose agar)

-Histology-biopsy specimens

-Look for Galactomannan (component of Aspergillus cell wall). If levels decreasing, see that treatment working

Question 22

Zoonotic/interspecies transmission

Answer 22

-not transmitted between individuals
-we get them from the environment

-occupational exposures: waste management workers working with organic waste, spores in degrading plants
*Susceptible to developing allergic bronchopulmonary aspergillosis

Question 23

Treatment of aspergillus

Answer 23

-Determine if local or systemic
-Azole drugs (Itraconazole, Voriconazole… NOT FLUCONAZOLE)
-Amphotericin B is another option
-Caspofungin possible but costly

Question 24

Mucor and Rhizopus resistance

Answer 24

Intrinsically resistant to voriconazole