35 – Aspergillus

Question 1

Microbiological characteristics

Answer 1

• Rapidly growing septate fungi
• Pigmented colonies blue-grey
• Conidiophores are unbranched (helpful to differentiated from Penicillium)
• Very small spores: can reach ends of bronchial tree
• Specialized media to grow: Rose Bengal agar (inhibits growth of bacteria)

Question 2

Natural host or habitat

Answer 2

• Ubiquitous in soil and decomposing material
• A. fumigatus: found in overheated, spiled hay
• Infections are UNCOMMON and usually SPORADIC
• Often involve respiratory tract
  o Infection
  o Hypersensitivity (more evidence in people)

Question 3

Aspergillus in young chickens

Answer 3

• Brooder pneumonia
• Young chicks exposed to large number of spores
• Nodules in lungs and air sacs
• Associated with dirty environments (hihgh load of spores)
• *good hygiene is key!

Question 4

Aspergillus in mature birds

Answer 4

• Inhalation of spore laden dust
• Clinical signs: dyspnoea and emaciation
• Nodules seen in lungs
• *’puff ball’ spores aerosolized when you open it

Question 5

What type of bird is particularly susceptible to Aspergillus?

Answer 5

• PENGUINS

Question 6

Aspergillus fumigatus in horses

Answer 6

• Guttural Pouch Mycosis
• Unknow what exactly predisposes to infection
• Often unilateral
• *fungus invades neuro/vascular structures
• Diagnose based on clinical signs and endoscopic examination
• *case fatality rate is 1/3
• *NO specific prevention/control measures

Question 7

What are the clinical signs of Guttural Pouch Mycosis in horses (A. fumigatus)?

Answer 7

• Epistaxis, dysphagia, laryngeal hemiplegia, facial nerve dysfunction
• *Horner’s syndrome
• Afebrile

Question 8

How do you treat guttural pouch mycosis in horses? (A. fumigatus)

Answer 8

• Prognosis poor without treatment
• Debridement of lesions
• Topical antimicrobial therapy (enilconazole, miconazole)
• Iatrogenic thrombosis and embolization of carotid
  o Prevents bleeding following debridement
  o Okay to ‘cut off’ one of them and be fine
• ?: Parenteral antifungals of questionable value (very expensive)

Question 9

Aspergillus in cattle

Answer 9

• Cause of mycotic abortion
• Sporadic disease
• Typically occurs 6-8 months into pregnancy
• Associated with poor quality feeds
• *reaches placenta HEMATOGENOUSLY
• No sign of systemic illness

Question 10

What do you see in the abortuses and the placenta due to mycotic abortion in cattle?

Answer 10

• Abortuses: ‘ringworm’ like lesions
• Placenta: necrotic cotyledons

Question 11

Aspergillus fumigatus nasal disease in dogs: clinical signs

Answer 11

• mucopurulent nasal discharge, epistaxis
• Sneezing
• Nasal discomfort (pawing at nose)
• Other signs of nasal disease (stridor or stertor)
• May have: nasal depigmentation
• **usually in immunosuppressive animals

Question 12

Aspergillus fumigatus nasal disease in dogs

Answer 12

• Can produce osteolytic toxins
  o Destruction of turbinate’s
  o Erosion of cribriform plate

Question 13

Aspergillus fumigatus nasal disease in dogs: diagnosis

Answer 13

• Physical exam + nasal workup (possibly including rhinoscopy)

Question 14

What aspergillus is seen in systemic disease of dogs?

Answer 14

• A. terreus
• A. deflectus

Question 15

Aspergillus fumigatus nasal disease in dogs: treatment

Answer 15

• Systemic therapy does NOT have good success rate (40-60%)
• Azole antifungals
• Hepatic toxicity
• Debride fungal plagues
• Topical fungal therapy
• Trephination of sinus
• *cribriform needs to be intact (do NOT want in brain)

Question 16

Aspergillus fumigatus nasal disease in dogs: topical antifungal therapy

Answer 16

• Enilconaozole or clotrimazole
  o 1% solution infused through catheters into nasal cavity
• Nasal infusions for ~1hr

Question 17

Aspergillus fumigatus nasal disease in dogs: trephination of sinus

Answer 17

• Fill with clotrimazole cream
• Close hole with bone wax

Question 18

Aspergillus fumigatus or flavus in humans: ‘3 disease types’

Answer 18

• RESPIRATORY SYSTEM
• 1. Allergic bronchopulmonary aspergillosis
• 2. Aspergilloma
• 3. Invasive aspergillosis
     *has an AFFINITY FOR INVADING BLOOD VESSELS (carotid a. in guttural pouch)

Question 19

Allergic bronchopulmonary aspergillosis (humans)

Answer 19

• Similar signs to asthma

Question 20

Aspergilloma (humans)

Answer 20

• Cough
• Hemoptysis
• Shortness of breath
• *fungus ball, matt of hyphae which develop secondary to other conditions
• *often in lungs

Question 21

Invasive aspergillosis

Answer 21

• Fever
• Chest pain
• Other signs depending on localization
• *very high mortality rates
  o 94% mortality in bone marrow transplant patients

Question 22

Swimmer’s ear in humans

Answer 22

• Aspergillus otitis externa
• Itching, pain, scaling

Question 23

Sample collection and handling

Answer 23

• Tissue biopsies: lung, nodules, nasal biopsies acquired rhinoscopically
• Abortuses: fetal abomasal contents, placental tissues
• Milk
• Scrapings
• Fungal plaques
• *do NOT freeze if you want to culture it

Question 24

Lab ID

Answer 24

• Direct microscopy (KOH preps of tissues)
• Culture: selective/differential media
• Histology
• *galactomannan ELISA in humans

Question 25

What is galactomannan?

Answer 25

• Component of cell wall of Aspergillus spp.
• People: quantatative ELISA to monitor response to therapy
  o If levels decrease=successful clinical strategy

Question 26

Zoonotic/interspecies transmission

Answer 26

• NOT transmitted between individuals: risk of transmission is VERY LOW
• More concerned with acquiring from ENVIRONMENT
• Possible occupational exposure

Question 27

What are some possible occupational exposures to Aspergillus?

Answer 27

• Waste management workers who work with organic waster
• Lots of spores in degrading plant material
• *susceptible to developing allergic bronchopulmonary aspergillosis

Question 28

Treatment options

Answer 28

• Localized or systemic?
• *azoles drugs for systemic
  o Itraconazole, voriconazole
  o *NOT fluconazole
• Amphotericin B may be good option
• Caspofungin: select cases of disseminated disease and if owners dedicated ($$)
• Other filamentous fungi are intrinsically voriconazole resistant