Mycology Part 1B Flashcards
(50 cards)
1
Q
What is Eumycotic Mycetoma?
A
- Tumorous, granulomatous infections of the skin and subcutaneous tissues caused by true fungi
- May rarely invade bone
- History:
- First reported in man in Madurai, India
- Maduramycotic mycetoma
- Chromoblastomycosis
- First reported in man in Madurai, India
2
Q
What is the clinical manifestation of Eumycotic Mycetoma?
A
- Tumorous granulomas
- Skin and subcutaneous tissues, rarely bone
- Abscesses with draining tracts
- Granules - Usually colored
3
Q
What Fungi are responsible for Eumycotic Mycetoma in animals?
A
- Pseudallescheria boydii
- Curvularia geniculata
- Helminthosporium spp.
- Madurell mycetomatis
- Cochliobolus spicifer
- Cladosporium werneckii
4
Q
How is Eumycotic Mycetoma diagnosed?
A
- Clinical Diagnosis:
- Granules in exudate
- Laboratory Diagnosis:
- Direct examination of exudate or crushed granules
- Demonstrate hyphae with or without spores
- Culture examination:
- Grow on Sabouraud Dextrose agar with or without antibiotics
- Identification difficult
- Direct examination of exudate or crushed granules
5
Q
What is the Epidemiology of Eumycotic Mycetoma?
A
- Not a contagious disease
- Wound contamination by soil or other infectious material
6
Q
What is the Treatment for Eumycotic Mycetoma?
A
- Most attempts are unsuccessful
- Surgical Removal
- Iodides
- Amphotericin B
- 5-Fluorocytosine
- Thiobendazole
- Ketoconazole
7
Q
What is Sporotrichosis?
A
- Caused by: Sporothrix schenckii
- Disease or horses, dogs, cattle, fowl, rats, hamsters, humans, mules, cats, camels, swine, mice, and primates
- Chronic and granulomatous
- Usually subcutaneous, rarely systemic
- Chronic and granulomatous
8
Q
What is the Prevalence of Sporotrichosis?
A
- Sporadic cases in endemic areas
- Ubiquitous saprophyte of plant material, esp. sphagnum or peat moss
- Primarily a wound infection
9
Q
What is the Pathogenesis of Sporotrichosis?
A
- Proteases -hydrolyses stratum corneum
- CMI response responsible for tissue reaction
- Cell contains lipid, melanin, peptide-rhamnomannan
10
Q
What is the clinical manifestation of Sporotrichosis?
A
- Subcutaneous abscesses - Most Common
- Small granulomas at site of wound
- Lesions most often on extremities
- Nodules ulcerated with brownish-red exudate
- Lymphangitis
11
Q
How does Sporotrichosis affect horses?
A
- Streptothricosis - Dermatophilus congolensis
- Glanders - Burkholderia mallei
- Ulcerative lymphagitis - Coryne pseudotuberculosis
- Epizootic lymphangitis - Histoplasma capsulatum var. farciminosusm
12
Q
How is Sporotrichosis Diagnosed?
A
- Laboratory:
-
Microscopic Examination of exudate
- Gram Stain
- New Methylene Blue
- Cigar Bodies (yeast cells)
- Dogs, horse, human - few or none
- Cats and Dogs testicular lesions - many cigar bodies
-
Cultural examination
- BA at 37C - Yeast phase
- Potato dextrose agar - black colonies
- Sabouraud Dextrose agar at 25C
- Grows in mycelial phase
- Small oval conidia on a short conidiophore
- convert mycelial to yeast phase for confirmation
-
Microscopic Examination of exudate
13
Q
What is the treatment for Sporotrichosis?
A
- Iodides - organic or inorganic
- Amphotericin B - toxicity
- Surgery contraindicated
- May cause dissemination and increase severity
- Griseofulvin
- Ketoconazole
- Itraconazole
- 5-Fluorocytosine
14
Q
What is Rhinosporidiosis?
A
- Caused by Rhinosporidium seeberi
- Chronic granulomatous infection of the mucous membranes of the nasal cavity
- Reported in:
- Horses
- Mules
- Cattle
- Humans
- Cat
- Dogs
- Goats
- Geese
- Ducks
15
Q
What is the Prevalence of Rhinosporidium seeberi?
A
- Sporadic in the U.S
- More cases are seen in humans than animals in endemic areas
16
Q
What is pathogenesis of Rhinosporidium seeberi?
A
- Likely CMI reaction
17
Q
What are the Clinical Manifestations of Rhinosporidium seeberi?
A
- Tumorous polyp-like growth in the nasal cavity
- Single or multiple
- Soft - bleed easily
- Mucopurulent nasal discharge
- Lobulated surface - cauliflower-like
- Small white specks on the surface (Sporangia)
- General health not impaired
- Not disseminated
- Affects breathing
18
Q
How is Rhinosporidiosis diagnosed?
A
- Laboratory
- Direct examination: squeeze out sporangia and examine on wet mount
- Round Sporangia: 300-350 micro meters with 16,000-20,000 spores (5-7 micrometers) inside
- Histopathology on biopsy of fixed tissue
- Not grown in laboratory media
19
Q
What is the epidemiology of Rhinosporidiosis?
A
- Not contagious
- Natural habitat unknown
20
Q
What is the treatment of Rhinosporidiosis?
A
- Surgery, but may reoccur
- Antimicrobials have no effect
- Variety of things have been tried - none highly successful
21
Q
What is Candidiasis?
A
- Caused by: Candida spp. (usually Candida albicans)
- Usually affects digestive tract of calves and poultry; also affects dogs, cats, and horses
- Swine - skin infections and gastric ulcers
- Cattle - Associated with mastitis and abortion
22
Q
What is the Prevalence of Candidiasis?
A
- Infections usually sporadic
- Highly fatal in poultry
23
Q
What is the pathogenesis of Candidiasis
A
- Organisms always present in digestive and urogenital tracts
- Opportunistic pathogen
- In immunocompromised individuals
- Diabetes, malnutrition, or AIDS
- Hormonal imbalance in women - vaginal
- Antibiotic or corticosteroids therapy
- Glycoproteins, proteases, lipases, neuraminidase, adhesins
24
Q
What is the clinical manifestation of Candidiasis in poultry?
A
- Crop Mycosis:
- Whitish-gray pseudomembrane on the mucosa with many yeast cells
25
What is the clinical manifestation of Candidiasis in calves?
* Infections o abomasum associated with antibiotic over therapy
26
What is the clinical manifestation of Candidiasis in swine?
* Gastric ulcers
27
What is the clinical manifestation of Candidiasis in Dairy Cows?
* Prolonged antibiotic therapy following mastitis
28
What is the clinical manifestation of Candidiasis in dogs?
* Systemic infections have been reported
29
How is Candidiasis diagnosed?
* Laboratory Diagnosis:
* Direct Examination
* Clear scraping in 10% KOH
* Gram stain scraping
* Cultural Examination
* Yeast cells on Sabouraud Dextrose agar, final identification difficult
* Commercial test kits
30
What is the Epidemiology of Candidiasis?
* Humans: transmitted at birth
* Animals:
* Likely at birth
* Direct animal to animal contact when in close confinement
* Endogenous
31
What is the Treatment for Candidiasis?
* **Discontinue antibiotic and/or steroid therapy**
* Nystatin ointment topically
* Amphotericin-B
* In Poultry 1:2000 copper sulfate in the drinking water
* **Miconazole, itraconazole, fluconazole**
* Flucytosine
32
What are the characteristics of *Malassezia pachydermatis?*
* Part of the normal flora of canine ear
* Antibiotic therapy for infections caused by other microorganisms (*Pseudomonas aeruginosa*)
* First described on he Rhinoceros - skin lesions
33
How is *Malassezia pachydermatis* cultured?
* Grows on;
* Blood agar at 37C
* Sabouraud Dextrose Agar
* Dermatophyte Test medium
* Gram stain:
* Typical budding yeast cells, some appearing like peanut shells
34
How is *Malassezia pachydermatitis* treated?
* Like *C. albicans* (Both cause Cndidiasis)
* Nystatin ointment topically
* Amphotericin-B
* Miconazole, itraconazole, fluconazole
* Flucytosine
35
What is Zygomycetes (phycomycetes)?
* Granulomatous diseases
* Affect a wide variety of tissues
* Important *Phycomycetes*
* *Mucor sp.*
* *Rhizopus sp.*
* *Absidia sp.*
* *Mortierella sp.* - cases of abortion
* *Rhizomucor sp.*
36
What is the pathogenesis of Zygomycetes?
* Tend to occur in individuals who are suffering from another primary condition
37
What are the Clinical Manifestation of Zygomycetes in horses?
* Ulcers and granulomatous lesions on lower leg
* Reported to cause granulomatous lesion at the muco-cutaneous junction of the mouth and nostril
38
What are the Clinical manifestations of Zygomycetes in other species?
* Dog:
* ulcers on the leg
* Otitis
* Calves: Abomasal ulcers
* Sheep: Respiratory infections
* Birds: Respiratory infections
* Cattle:
* Placental lesions
* Mycotic rumenitis
* Abortion - *Mortierella sp.*
39
How is Zygomycetes diagnosed?
* Clinical:
* Usually made at necropsy
* In living animal or at necropsy, biopsy or smear from infected tissue
* Should demonstrate aseptate, broad hyphae
* Laboratory:
* Direct Examination
* Aseptate, broad hyphae in smear from lesion
* Histopathology on necropsy or biopsy tissue
40
What are the predisposing factors for Zygomycetes?
* Horses standing in water or mud (OKA: "Leaches")
* Cattle: overload of the rumen and rumenitis with resulting invasion of ruminal wall with the fungus
* Result in rupture of the rumen
* Neoplasia
* Immunosuppressive therapy or disease
41
What is the treatment for Zygomycetes?
* Surgery
* Amphotericin - B
42
What is Aspergillosis?
* Systemic Mycoses
* Caused by: *Aspergillus spp.*
* Primarily infections of the respiratory tract
* Can also affect eyes skin, meninges, reproductive tract
* Infections in mammals are rare
* Commonly see infections in birds - domestics and wild
* Common bread mold
43
What is the pathogenesis of Aspergillosis?
* Most infections likely contracted by **inhalation** of spores
* Adhesins, lipases, proteases
44
What are the clinical manifestations of Aspergillosis in birds?
* Brooder pneumonia
* Young birds are very susceptible
* Septicemia and fungus throughout body
* Very high morbidity and mortality
* Chronic air sacculitis in wild birds
* Fungus grows in air sacs - sporulates
45
What are the clinical manifestations of Aspergillosis in horses?
* Nasal sinus infections
* Meningeal involvement
* Generalized infection - rare
* Diarrhea in young horses - rare
* Abortions in horses have been reported - rare
46
What are the clinical manifestations of Aspergillosis in Cattle?
* Multiple granulomas in the lungs
* Abortions
* Retained placenta
* Placenta thickened and leathery
47
What are the Clinical manifestations of Aspergillosis in other animals?
* Pulmonary granulomas
* Dogs, cats, sheep
* Disseminated infection
* dogs
48
How is Aspergillosis diagnosed?
* Use caution when cultured
* a ubiquitous saprophyte - make sure you have not cultured a contaminant
* **Direct microscopic examination**
* **Demonstrate septate hyphae**
* May see sporulation in air sacs of birds like that seen on agar
49
What is the culture of Aspergillosis?
* Sabouraud Dextrose agar
* Black = *A. niger*
* Green/yellow = *A. flavus*
* Bluish-green = *A fumigatus*
* Gray = *A fumigatus*
* Pink/Yellow/Orange = *A. glaucus*
* Lacto-phenol-Cotton Blu tease mount
* Demonstrate typical morphology
50
What is the treatment for Aspergillosis?
* Not practiced in birds
* Best to follow good sanitary measures to prevent Brooder pneumonia
* Other animals - Poor prognosis
* Ketoconazole
* Nystatin
* Amphotericin - B
* 5-Fluorocystine
