Baker's/Brewer's Yeast

(first eukaryotic cell to have its entire genome sequenced)

2 forms of temperature dependent fungus:

Mold at less than 30˚C ("cold mold")

Yeast at 37˚C

Dermatophytes

Candida

Pneumocytis

Histoplasma

Blastomyces

Coccidioides

Paracoccidioides

Aspergillus

Candida

Cryptococcus

Pneumocytis

Aspergillus fumigates

Candida albicans

Cryptococcus neoformans (have capsule that prevents phagocytosis)

Endospores = protection

Spores = reproduction

Amphotericin B

("gold standard" for antifungal agents; most toxic to humans; not 1st line drug; target ergosterol and punch holes in its cell membrane)

Ketoconazole

Griseofulvin

Causes Blastomycosis

Cutaneous ulcers causing abscess formation and tissue destruction

Pulmonary blastomycosis = most common manifestation in humans; respiratory failure & death in immunocompromised people

May lead to cutaneous, osteoarticular, or meningitis in AIDS pt

Located around Mississippi River

Spherules which enlarge and generate more spores

Usually asymptomatic (night sweats)

Located in dry southwestern states

Most common fungal pathogen affecting humans

Carried by bats and humans

Located in West Africa and around Mississippi River

Begins in the lungs

Disseminates mucous membranes around the mouth

Steering wheel shaped pathogen

Located in Paraguay and Brazil

Cause hypersensitivity aspergillosis, noninvasive aspergillomas, acute invasive pulmonary aspergillosis, cutaneous and systemis aspergillosis

Aspergillus fumigates = AIDS defining

Aspergillus flavus = alfatoxin (liver damage and liver cancer)

Causes thrush, diaper rash, intertrigo, vaginitis, onchymycosis, ocular candidiasis,

and meningitis (in AIDS pt)

AIDS defining pathogen

Has capsule prevent phagocytosis

From pigeon droppings

Causes cryptococcal meningitis (fatal in AIDS pt)

AIDS defining pathogen

Causes pneumocytis pneumonia

Common opportunistic fungal infection in AIDS pt

Superficial mycoses:

Piedra

Malassezia furfur

Black piedra = Piedraia hortae

White piedra = Trichosporon beigelii

Malassezia furfur = pityriasis, folliculitis,

and seborrheic dermatitis

Tinea versicolor - pityriasis

(will illuminate green)

Common dermatophytoses:

Tinea pedis

Tinea cruris

Tinea unguium

Tinea corporis

Tinea capitis

Tinea pedis = athlete's foot/jungle rot

Tinea cruris = jock itch

Tinea unguium = yellow nails

Tinea corporis = ringworm

Tinea capitis = cradle cap

Rose gardener's disease

Nodular lesions

Aspergillus flavus/mycotoxin/alfatoxin

Causes liver damage and liver cancer

Claviceps purpurea = useful product of ergot alkaloids (drugs = Ergometrin & Ergotamine)

Fungi = Amphotericin B

Protozoa = Metronidazole / Flagyl

Only ciliate known to cause disease in humans

Tx = tetracycline & Flagyl

Pigs are the most common host

(no defined shape)

Entamoeba histolytica

Naegleria fowleri

Causes amebic dysentery

Humans are primary host

Some humans are asymptomatic carriers

No animal reservoir

Invades mucosa (voluminous diarrhea & bloody stools)

"Night soil" = human feces for fertilizer

Swimmers inhale contaminated water

Migrate to brain and cause amebic meningoencephalitis

Coma and death in 4-5 days

No Tx

(at least one flagella)

Trypanasoma brucei

Trypanasoma cruzi

Leishmania species

Giardia intestinalis

Trichomonas vaginalis

Causes Africa Sleeping Sickness

Vector = Tsetse fly

Leads to meningoencephalitis (drowsiness, coma, and death)

Causes Chaga's disease/American trypanasomiasis

Vector = reduviid/kissing/assasin bug

Affects heart, esophagus, and large intestine

Parasite induced heart disease = leading cause of death in Latin America

Causes Leishmaniasis

Vector = female sand fly

Can be cutaneous, mucocutaneous, or visceral

Common GI disease

Causes Giardiasis or "beaver fever"

Cysts look like ghosts

Causes STD, Trichomoniasis

Cannot live long outside host

Men are asymptomatic

Plasmodium - falciparum, vivax, ovale, malariae

Toxoplasma gondii

Cryptosporidium parvum

Cyclospora cayetanensis

Cause malaria

Vector = female anopheles mosquito

Plasmodium falciparum = worse malaria

Merozoites penetrate RBCs and undergo schizogony

Mal-aria = bad air; "Swamp smells"

Resistant to malaria: Sickle cell (HgbS); HgbC; Glucose-6-Phosphate-dehyrdogenase deficiency; lack of duffy antigen on RBCs

Causes Toxoplamosis

Cat = definitive host

Can cross the placenta

Tx: self-limiting; antimalarial drugs

Carried by livestock and poultry

From contaminated water

Life-threatening in AIDS pt with cholera-like diarrhea

Cestodes/tapeworms

Trematodes/flukes

Nematodes/roundworms

Hookworms - ancylostoma duodenale & Necator americanus

Pinworm - Enterobius vermicularis

Wuchereria bancrofti

Cestodes/tapeworms:

Taenia solium

Taenia saginata

Echinococcus granulosus

Diphyllobothrium latum

3 parts = scolex, proglottids, stobila

Cysticerci = immature tapeworm

Lack digestive system, but absorb soluble nutrients

Taenia solium = pig tapeworm

Taenia saginata = cow tapeworm

Echinococcus granulosus = dog tapeworm (causes hydatid disease with hyatid cysts; has 3 proglottids)

Diphyllobothrium latum = fish tapeworm (largest tapeworm)

Trematodes/flukes:

Schistosoma - mansomi, japonicum Schistocoma haematobium

Fasciola - hepatica, gigantica

Snail = intermediate host

Cause schistosomiasis/Snail Fever

Cercariae = larvae of fluke; cause dermatitis (Swimmer's itch)

Lack complete digestive system (no anus)

Schistosoma - mansomi, japonicum = live in mesenteric veins; eggs die and calcify leading to fatal tissue damage

Schistosoma haematobium = causes urinary tract schistosomiasis; blood in urin; found in Africa and India

Fasciola - hepatica, gigantica = infect liver of sheep and cattle

Nematodes/roundworms:

Ascaris lumbricoides

Largest nematode to infect humans

Most common nematode infection worldwide

Causes ascariasis

Double route through GI tract

Hookworms:

Ancylostoma duodenale

& Necator americanus

Larvae burrow between toes

Causes ground itch

Pinworm:

Enterobius vermicularis

Most common parasite worm in the US

Common s/s = perianal itching

Spread via fecal-oral route

Causes filariasis or elephantiasis

Infects human lymphatic system

Vector = particular genus of female mosquito

Arachnida = 8 legs (ticks & mites)

Insecta = 6 legs; 3 body parts; largest animal group (flea, lice, tsetse fly, mosquito, kissing bug)

Yeast = budding reproduction; unicellular

Mold = spore reproduction; multicellular

Intermediate Host

vs.

Definitive Host

Intermediate host = carries immature parasites

(one or more); asexual reproduction

Definitive host = carries mature parasites

(always); sexual reproduction

Parasitologist

vs.

Mycologist

Parasitologist = studies infectious diseases caused by protozoa and helminthes

Mycologist = studies the diagnosis, management, and prevention of fungal infections

Dermatophytes are "emerging opportunistic pathogens"

Most commonly reported fungal disease

Mycoses are localized at sites at or near the surface of the body

Found on barber shop clippers and shower room floors

Plasmodiums

&

Wuchereria bancrofti

How are all pathogenic fungi acquired?

What are 3 precautions from fungal spores?

Through inhalation of spores

Three precautions:

HEPA filters, hoods, and protective clothing