Fungi and Protozoans

What are dermatophytes?

Fungi that invade keratinized tissue causing dermatomycoses

Tinea corporis

Ringworm of the body

Tinea capitis

Ringworm of the scalp

Tinea cruris

Ringworm of the groin

Tinea unguium

Ringworm of the nails

Tinea pedis

Athlete’s foot; may have secondary bacterial infection

Candida albicans normal role

Normal flora; opportunistic pathogen

Diseases caused by Candida albicans

Thrush, vaginitis, tissue infections, nosocomial infections

Risk factors for candidiasis

Immunocompromised, antibiotics, diabetes, hormone or pH changes

Candida auris

Emerging drug-resistant hospital fungal infection; bloodstream spread

Trichomoniasis causative agent

Trichomonas vaginalis

Transmission of Trichomonas vaginalis

Sexually transmitted

Symptoms of trichomoniasis

Females often symptomatic; males usually asymptomatic

Trichomonas hominis and T. tenax

Normal commensals

Coccidioidomycosis causative agent

Coccidioides immitis

Geographic location of Coccidioides

Southwest United States (Valley Fever)

Diagnostic structure of Coccidioides

Spherule filled with spores

Histoplasmosis causative agent

Histoplasma capsulatum

Geographic location of Histoplasma

Central and eastern United States

Key feature of Histoplasma

Survives and multiplies inside macrophages

Pneumocystis pneumonia causative agent

Pneumocystis jirovecii

Who is most affected by PCP

AIDS and immunocompromised individuals

Blastomycosis causative agent

Blastomyces dermatitidis

How Blastomyces spreads

Spores inhaled or enter wounds; systemic spread via macrophages

Aspergillosis causative agent

Aspergillus fumigatus

Source of Aspergillus spores

Decaying vegetation

Giardiasis causative agent

Giardia duodenalis

Infective form of Giardia

Cyst

Unique feature of Giardia

Adhesive (suction) disk

Giardia and chlorination

Not killed by chlorine

Amebiasis causative agent

Entamoeba histolytica

Where Entamoeba invades

Colon and bloodstream

Serious complication of amebiasis

Peritonitis

Cyclosporiasis causative agent

Cyclospora cayetanensis

Common source of Cyclospora

Contaminated food (berries) or water

Cryptosporidiosis causative agents

Cryptosporidium hominis and Cryptosporidium parvum

Who gets severe cryptosporidiosis

Immunodeficient individuals

Visceral leishmaniasis vector

Sand fly

Key feature of Leishmania

Survives inside macrophages

Malaria vector

Female mosquito

Malaria life cycle order

Sporozoite → liver → merozoite → RBC → fever

Most severe malaria species

Plasmodium falciparum

Who is protected from malaria

People with sickle cell trait

Chagas disease causative agent

Trypanosoma cruzi

Vector for Chagas disease

Reduviid bug

Organs damaged in chronic Chagas disease

Heart, skeletal muscle, colon

Toxoplasmosis causative agent

Toxoplasma gondii

Sources of Toxoplasma

Cat feces and undercooked meat

Special risk of toxoplasmosis

Congenital defects and AIDS complications

Cryptococcosis causative agent

Cryptococcus neoformans

Source of Cryptococcus

Bird droppings

Disease caused by Cryptococcus

Meningitis in AIDS patients

African sleeping sickness causative agent

Trypanosoma brucei

Vector for African sleeping sickness

Tsetse fly

Why no vaccine for African sleeping sickness

Antigenic variation of surface proteins