Lecture 6: Opportunistic Fungi

Question 1

Where is pythium insidiosum found around world

Answer 1

tropical/subtropical areas

Question 2

pythium species generally found as __pathogen

Answer 2

plant

Question 3

Pythium insidiosum is an oomycete- what is that

Answer 3

water mold

Question 4

pythium insidosum is a flagellated __ capable of invading __

Answer 4

zoospores, damaged epithelium

Question 5

pythium insidosum commonly infects where on body

Answer 5

limbs/ abdomen, GI

Question 6

what species is most commonly infected with Pythium insidiosum

Answer 6

horses

Question 7

pythium insidiosum life cycle depends on ___to persist in the environment

Answer 7

plant infections

Question 8

Important part of case hx for Pythium insidiosum is exposure to __

Answer 8

water/flooding

Question 9

what is pathogenesis for pythium insidiosum

Answer 9

1. zoospores adhere to damaged skin or ingested
2. spores invade tissue via germ tube, eventually forming aseptate hyphae
3. Hyphae extend into tissues, lymphatic, blood vessels and disseminate
4. Tissue damage is a result of eosinophilic/ mast cell degranulation

Question 10

what lesions are seen on horse with pythium insidiosum

Answer 10

granulomatous, ulcerative lesions of the limbs/ abdomen, sometimes enteric with crater like borders

Question 11

pythium insidiosum is occasionally seen in ___dogs. __ and __ forms can occur

Answer 11

young dogs
Cutaneous and gastrointestinal forms

Question 12

how do you dx pythium insidiosum

Answer 12

1. Clinical hx-exposure to water
2. Histology- PAS/GMS/ IHC
3. PCR or MALDI

Question 13

what is tx for pythium insidiosum

Answer 13

surgical debridement, immunotherapeutic vaccination, and amphotericin B

Question 14

how do you prevent pythium insidosum

Answer 14

limit exposure to wet or swampy areas in endemic areas

Question 15

sporothrix schenckii inhabits ___rich in organic matter

Answer 15

soil

Question 16

sporothrix schenckii infection linked to contact with __ or __

Answer 16

plants or infected animals

Question 17

what is pathogenesis of sporothrix schenckii

Answer 17

1. Inoculation of filamentous propgagules into skin
2. Yeast form slowly disseminates via lymphoreticular system

Question 18

What is primary contact with sporothrix schenckii

Answer 18

mycelia in environment

Question 19

How is sporothrix schenckii horizontally transmitted

Answer 19

yeast forms from infected host

Question 20

what species is sporothrix schenckii most common in

Answer 20

cats

Question 21

what lesions are associated with sporothrix schenckii

Answer 21

primary nodular lesions and secondary ulcerative lesions with draining tracts

Question 22

how do you dx sporothrix schenckii

Answer 22

1. Unresponsive to abx
2. Impression smears
3. PCR or maldi

Question 23

what is tx for sporothrix schenckii in cats and dogs

Answer 23

itraconazole

Question 24

what is tx for sporothrix schenckii in horses

Answer 24

systemic iodides

Question 25

how do you prevent sporothrix schenckii

Answer 25

indoor housing, neuter, proper PPE to prevent zoonosis

Question 26

pneumocystisi jirovecii was previously classified as Protozoa due to its __ and __ stages

Answer 26

sporozoite and trophozoite

Question 27

what are some breed predilections to pneumocystis jirovecii and what is it linked to

Answer 27

KCCS, dachshund, Arabian horses with links to immunodeficiencies

Question 28

what is the source of pneumocystis jirovecii

Answer 28

environmental source

Question 29

what is the infectious form of pneumocystis jirovecii

Answer 29

trophozoite

Question 30

what is the generative form of pneumocystis jirovecii in the host

Answer 30

sporozoites/cysts

Question 31

What is the pathogenesis of pneumocystis jirovecii

Answer 31

1. Inhalation and trophozoite attachment to type I pneumocytes 2. Cyst formation

Question 32

clinical disease from pneumocystis jirovecii is rare but __-are thought to serve as reservoirs

Answer 32

immunocompetent animals

Question 33

what species is pneumocystis jirovecii most common in

Answer 33

dogs

Question 34

what are some clinical signs of pneumocystis jirovecii

Answer 34

chronic respiratory symptoms- cough, tachypnea, dyspnea

Question 35

how do you dx pneumocystic jirovecii

Answer 35

BAL, histology/GMS/PAS, PCR

Question 36

what is tx for pneumocystis jirovecii

Answer 36

trimpethoprim-sulfa, low dose steroids