Fungal Infections

Question 1

What are fungi as infectious agents?

Answer 1

-Fungi are distributed in air, dust, fomites, and normal flora
-Humans are kind of resistant
-Fungi are nonpathogenic
-fungi are most common plant pathogens

Question 2

What are fungi eukaryotes?

Answer 2

-defined nucleus
-free-living
-parasitic on living host

Question 3

How do fungi cause disease by?

Answer 3

-invading tissue , giving an allergic response
-toxins in food- toxicosis

Question 4

Classification of Pathogenic Fungi?

Answer 4

Type of infection: superficial mycosis(hair, skin, nails)
-deep mycosis: affects internal organs (lung, kidney, brain)

Question 5

What are growth characteristics for fungi?

Answer 5

-filamentous -molds(hyphae)
-yeast (single cell)
-dimorphic fungi(yeast and mold)
*Thermal dimorphism: grow as molds at 30 and yeast as 37

Question 6

Systemic Infections by True Pathogens?

Answer 6

Histoplasma Capsulatum
Coccidioides immitis

Question 7

What is Histoplasmis:Ohio Valley Fever

Answer 7

Histoplasma capsulatum – most common true
pathogen; causes histoplasmosis
* Typically dimorphic ( mold and yeast)
* Grows in moist soil high in nitrogen content (bird
droppings)
* Inhaled caused pulmonary infection that may progress
to systemic involvement of a variety of organs and
chronic lung disease.
* Self-limiting: immune system takes care, it can be fatal
if it spreads to other organs

Question 8

What is cutaneous Mycoses?

Answer 8

Infections strictly confined to keratinized
epidermis (skin, hair, nails) are called
dermatophytoses - ringworm and tinea
* Trichophyton, Microsporum, Epidermophyton

Question 9

What is dermatophytosis (ringworm)

Answer 9

Dermatophytosis (ringworm)
- Dermatophytes
*live on the skin, hair, and nails
- Anthrophilic: human to human
- Zoophilic: animal to human
- Geophilic: are rare in soil, can cause
infection following contact
with contaminated soil

Question 10

What is trichophyton(Athletes foot)?

Answer 10

Trichophyton - Athlete’s foot
- direct contact
*sports facilities, locker rooms, pool
*foot wear (moist and warm)
*Symptoms:
* itching
* skin peeling
* macreation and fissuring of toe webs
* nail infections (discolor, crumbly, flaky
*zoophilic

Question 11

What is microsporosis?

Answer 11

microsporosis
(microsporum)
- scalp infection in children
- beard infection
- small papule and then spreads to scaly patches
of temporary baldness
-transmission: skin to skin
clothing
barber shops
back of seats
—– cats, dogs, cattle , horses, rodents

Question 12

What are opportunistic mycoses?

Answer 12

Most important fungal pathogens:
 Aspergillus
 Candida
 Cryptococcus
 Pneumocystis

Question 13

What is candida albicans?

Answer 13

Normal flora of oral cavity, genitalia, large intestine
or skin of 20% of humans
* Account for 80% of nosocomial fungal infections
* Thrush – occurs as a thick, white, adherent growth on
the mucous membranes of mouth and throat
* Vulvovaginal yeast infection – painful inflammatory
condition of the female genital region that causes
ulceration and whitish discharge
* Cutaneous candidiasis – occurs in chronically moist
areas of skin and in burn patients
Candidosis…opportunist yeast
under immunosuppression it may cause disease

Question 14

What is cryptococcosis?

Answer 14

• A encapsulated yeast that inhabits soil around pigeon roosts
  -common infection of AIDS, cancer or diabetes patients
  infection of lungs lead to cough, fever, and lung nodules
  -dissemination to meninges and brain can cause severe mengitis and death

Question 15

What is pheumocytstis jioveci and pneumocystis pneumonia?

Answer 15

-a small unicellular fungus that causes pneumonia, the most prominent opportunistic infection in AIDS patients
-forms secretions in the lungs that block breathing and can be fatal if not treated with meds

Question 16

What is disease of the genus aspergillus?

Answer 16

It is a common airborne soil fungus
-serious opportunistic threat to AIDS, leukemia, and transplant patients
-infection usually occurs in lungs-spores germinate in lungs and form fungal balls ; can colonize sinuses, ear canals, eyelids, and conjuctiva
-invasive aspergillosis can produce necrotic pneumonia, and infection of brain, heart, and other organs

Question 17

What are fungal allergies and intoxications?

Answer 17

-fungal spores are common source of allergies
-seasonal allergies and asthma: farmer’s lung, tea picker’s lung, bark stripper’s disease
-fungal toxins lead to mycotoxicoses usually caused by eating poisonous or hallucinogenic mushrooms
-aflatoxin toxic and carcinogenic ; grains, corn peanuts, lethal to poultry and livestock