2. Opportunistic pathogen
Attaches to human epithelial cells as a yeast
Usually it requires pseudohyphae to invade deeper tissues
Buds form a short
chain of cells called
a pseudohypha
Candida albicans
3. Pityriasis in a Caucasian patient
Pityriasis in an African-american
patient
Malassezia furfur and pityriasis versicolor
4. Malassezia furfur and pityriasis versicolor
10% KOH,
glycerol, and
Parker ink
solution
Diagnostic: Stained skin scrapings from patients reveal
thick-walled, round yeast cells that reproduce by budding,
and hyphae
6. Dimorphic fungi
Histoplasma capsulatum
Pathogenic dimorphic fungi and systemic mycoses (diseases caused by
fungi that can spread throughout the body)
Endemic of North America
Coccidioides immitis - Coccidioidomycosis
Histoplasma capsulatum – Histoplasmosis
Blastomyces dermatitidis - Blastomycosis
7. Arthroconidia inhaled from soil
germinate in the alveoli
Coccidioides immitis causes coccidioidomycosis
Diagnosis
Identification of spherules in
clinical specimens
Mild respiratory symptoms
More severe infections
involving
Coughing up blood
Pneumonia/Meningitis
8. Schistosoma mansoni
Blood fluke
Flukes are given names
according to the tissue of
the definitive host in which
the adults lives
Lung fluke
Liver fluke
Blood fluke
Cause progressive damage
to tissues and organs
Trematodes
12. Ascaris lumbricoides
Nematode-round worm
Infects over one billion people worldwide
Small intestine
Feeds on partially digested foods
Eggs excreted with feces can survive for long periods
16. Enterobius vermicularis
Eggs
The female migrates to the anus to deposit eggs on the perianal
skin at night (Diagnosis: Graham sticky-tape method)
17. Hookworms (nematode)
Necator americanus
Ancylostoma duodenale
Larvae infective for humans by penetrating the
host’s skin
Live in the small intestine of humans
Feed on blood and tissue leading to anemia
21. Giardia intestinalis
Trophozoites
Adheres to small intestine causing diarrhea
Trophozoite is the feeding/growing stage
Cyst is the survival stage
Diagnosis: identification of
cysts in feces
22. Pathogenic amoeba
Human intestine,
causes amebic
dysentery
Ingestion of cysts
excreted in the feces
of infected person
Presence of ingested red blood
cells is diagnostic of Entamoeba