Mycology 7

What are the FOUR types of Pseudofungi?

Rhinosporidiosis

Protothecosis

Pythiosis

Lagenidiosis

T/F Clinically distinguishing these infections is important because of differences in epidemiology, treatment, and prognosis

True

Why were the four Pseudofungi considered fungal infections?

based on their clinical & histopathological presentation

What are the THREE reasons why it is important to clinically distinguishing these infections?

differences in epidemiology, treatment, and prognosis

What Pseudofungi is an aquatic protistan parasite,closely related to pathogens of fish?

Rhinosporidiosis

What does Rhinosporidiosis cause? (3)

Granulomatous infection of mucous membranes

Hyperplastic tumor-like mucosal polyps

Where will you typically see Hyperplastic tumor-like mucosal polyps that Rhinosporidiosis causes?

nasopharynx and ocular conjunctiva

What climate will you typically see Rhinosporidiosis in and where will you find it in the US?

•Warm, wet environments

•Southeast, Southcentral

•CA, MI, and MI

Is Rhinosporidiosis zoonotic?

yes

What is the mode of transmission for Rhinosporidium seeberi?

Unclear, but possibly contaminated water sources in association with trauma

Where do you most commonly see Rhinosporidium seeberi?

nasal cavity

Rhinosporidium seeberi causes granular, multi-lobed & red due to vascularity. What does this mean in terms of vascular and bleeding ability?

Heavily vascular - bleeds easily.

What are the FIVE species that Rhinosporidiosis is common in?

Which animal is it rare in?

cattle, dogs, horses, swans, and humans

cats

How would you describe the mass cause by Rhinosporidiosis and where would you find it?

Polypoid pink mass protrudes from the nasal cavity

What does Rhinosporidiosis produce in the host tissue that contains endospores that are release upon maturation?

Sporangium

What are five differentials for Rhinosporidiosis?

•Nasal neoplasia

•Cryptococcosis

•Sinonasal aspergillosis

•Nasal mites

•Foreign bodies

How would you diagnose Rhinosporidiosis?

What makes it different than other infections?

Microscopic examination

Cannot be cultivated in the laboratory

What are the TWO stains that you can use for Rhinosporidiosis?

Observe via fungal stains, H & E staining & KOH

How do you treat Rhinosporidiosis?

surgical excisions

What is one way to prevent recurrence of the Rhinosporidiosis mass?

cauterization site ( Due to vascularity animals can bleed out)

Where are the common places that Prototheca species disseminates to?

common sites are skin, eye, GI prefers well vascularized sites.

What are the FOUR spp of Protothecosis?

Prototheca wickerhamii

Prototheca ciferri

Prototheca bovis

Prototheca blaschkeae

____ ____ ____ characterized by multifocal, round, and elongated, white, subretinal infiltrates (arrows) and serous retinal detachment (D) are evident

Posterior granulomatous uveitis

How is Protothecosis transmitted?

Transmission by direct contact or traumatic inoculation.

Protothecosis is thought to cause illness that develops when immune resistance is suppressed or altered due to preexisting or concurrent disease. What does this mean that the host lacks?

CMI

What TWO breeds of dogs and their hybrids are predisposed to Protothecosis?

Boxers, French Bulldog

What do Protothecosis lacks so lives in sludge, manure?

chlorophyll

How would you describe the appearance of Protothecosis?

Unicelluar, oval to spherical organisms

How does Protothecosis reproduce?

•reproduce via internal septation

What form of Protothecosis does cats, dogs, and humans get?

cutaneous

What form of Protothecosis do only humans get?

subcutaneous

What animal gets disseminated Protothecosis?

What body systems does it involve? (3)

canine

GI, Ocular, Neuro

Protothecosis has ____ for well-vascularized tissues - eye, CNS, kidneys & heart w/ spreads by blood & lymph

tropism

•Colitis may vary in severity, often ____ and present for months prior to signs

episodic

What are the TWO samples that you would want to do for cytology if you suspect Protothecosis?

Rectal scrape and urine sediment

T/F Cats will have a slow progression with a fatal outcome

False, dogs

Even though it is rare, how would Protothecosis present in dairy cattle?

Painful udder w/ watery milk; Limited to udder & regional lymph node

Due to their _____ ____ nature, Protothecosis makes it hard to eradicate so most of the animals infected are ____

Intracellular organism

culled

How would you preform a microscopic diagnosis of Protothecosis?

What do they resemble?

On Gram stain or Diff Quik stain solid & resemble a yeast form

What else can you do to diagnose Protothecosis?

Culture

T/F Protothecosis cure w early diagnosis, easier to treat algal colitis

True

What drug is used for systemic treatment of Protothecosis?

Amphotericin B

What pseudofungi is an aquatic pathogen

that causes cutaneous or intestinal infections in man and animals (horses and dogs)

Pythium insidiosum

What is a risk factor for dogs developing Pythiosis?

Exposure to fresh water habitats (lakes, ponds, swamps)

What demographic of dogs are predisposed to getting Pythiosis?

young large breed male dogs

Where is the incidence of disease for Pythiosis higher?

Gulf coast states

How are Pythiosis lesions characterized?

severe granulomatous & eosinophilic inflammation

What is more commonly seen in large animals infected with Pythiosis?

Yellowish to gray kunkers

What is Kunkers?

necrotic tissue, eosinophils, hyphae

Cutaneous Pythiosis is characterized by ___ wounds, invasive ____ w/ ulcerated nodules & draining tracts.

There is a (short/long) time frame between exposure and nodule formation.

nonhealing

masses

short

T/F Pythiosis rapidly progresses

True

How are Pythiosis lesions in horses?

large, circular, granulomatous, ulcerated, fistulated nodules, w/ yellow-gray necrotic masses or cores.

What type of involvement does chronic pythiosis have?

bone

What animal is kunker most obvious in?

horses

Where is Pythiosis common in the GI tract?

stomach, small intestine, & ileocolic junction

What do the Pythiosis lesions of the GI tract look like?

severe thickening of the intestinal wall, with enlargement of mesenteric lymph nodes.

What are some clinical signs of Pythiosis in the GI tract?

Anorexia, vomiting, weight loss

What will you grossly see with Pythiosis?

Mucosal hemorrhage w/ variable ulceration

How can you avoid gettinf pythiosis?

Avoid contaminated water

How would you do a Microscopic examination for Pythiosis?

What would you be looking for?

Exudate and tissue in KOH

broad, relatively nonseptate hyphae

What can you use to easily visualize pythiosis?

silver stain (GMS) or PAS

What is the THREE step process to ID PYTHIOSIS?

1. culture 2. PCR or 3. Serology

Pythiosis: Diagnosis

Culture:

Susceptible to ___ temperature

Grows as a mold at ___ C

Holding medium: ___ w/ ___ store at RT < 24 hrs.

___ ___, flat and irregular colonies.

Motile _____

cold

29 C.

saline w/ antibiotics

Silvery white

zoospores

T/F Pythiosis antibodies are diagnostic, not protective

True

How do you treat Pythiosis?

Surgical excision

Immunotherapy

Describe the EQUINE Immunotherapy protocol

a series of ID or SC injections of killed, sonicated, whole-cell hyphal AG or precipitated soluble antigens of the causative fungus.

T/F abt 20% of dogs respond to long term antifungal therapy after surgery

True

What are the THREE antifungal agents that can be used to treat Pythiosis?

Itraconazole

Terbinafine

Caspofungin

For unresectable lesions, what should you do?

itraconazole + terbinafine + tapering prednisone

Lagenidium is a ____ and is associated with ____

Oomycete

water

L. giganticum (_____ parasite) produces motile zoospores like Pythium & resides in the aquatic environment as a _____.

mosquito

saprophyte

What form of Lagenidiosis infection w/ systemic involvement?

Aggressive cutaneous

Which form less aggressive ; chronic ulcerative nodules w/ prolonged course

Progressive cutaneous

How would Lagenidiosis look microscopic examination?

Exudate and tissue in KOH (10X, 40X)

Examine for broad, relatively nonseptate hyphae.