Eukaryotic Pathogens (Protists, Fungi & Worms) & Acellular Pathogens (Prions)

protists

• found mostly in areas where there's water

• fungi-like

• protozans

• algaes

• parasites- spread by fecal oral route (most lived in water)

• (+,-) host=alive

• alt route- through interaction with other animals/organisms

digestive system and blood

target of protists

protozoans

animal-like protists

algaes and seaweeds

plant-like protists

Trophozite (troph)

the active feeding form of a protists

(vegetative equivalent)

cyst

non active "survival" form of protists, metabolically inactive

(endospore equivalent)

Dysentery

infection of the intestines resulting in severe diarrhea with the presence of blood and mucus in the feces.

Giardia lamblia


• can be in the cyst or troph form

• causes you to get dysentery- from drinking it in water

flagellates 


• use flagella

• back and forth movement

• Examples: Giardia (dysentery), Trypanosoma (sleeping sickness)

Sarcodinans (Pseudopods) 


• "false feet"

• stretches out & catches up

• examples: Entamoeba histolytica (dysentery)

Ciliates (cilia) 

Example: Balantidium coli (diarrhea & dysentery)

Apicomplexa (others)


• neither flagella, cilia, or pseudopods

• some use gliding

• Examples: Plasmodium falciparium (Malaria, transmitted by mosquitos), Toxoplasma (undercooked meat, cat feces)

Malaria

• transmitted by mosquitos

• grows in blood

• cause agent- Plasmodium

• more common in warmer temperatures- around equator

Sickle Cell Anemia


• recessive aa gene- don't live long

• Aa gene= carrier

• has some circular cells, some sickle cells

• cells provide protection against malaria

Fungi

• uni (yeast) or multi (mold) cellular

• comprised of euk cells

• are heterotrophs (carbon source= organic)

• have cell walls (chitin)

• most are SEDENTARY

• major role= decomposers

• Saprophytes- feed of dead tissue

skin and respiratory systems

target of fungi

saprophytes

feed off dead tissue

yeast

• unicellular fungi

• 3-5 um diameter

mold

• multicellular fungi

• tubular filaments (hyphae) 

• 2-10 um in diameters, filaments can be cm long 

mycosis

fungal disease

systemic (fungal disease) 


not restricted to any particular region or tissue

subcutaneous (fungal disease) 


beneath the skin

cutaneous dermatophytes (fungal disease) 


grown on skin and nails

superficial (fungal disease) 


localized along hair shafts

opportunistic mycoses (fungal disease)


fungus we already have that makes us sick

ex: yeast infection (overgrowth of already made yeast)

pseudohyphae

chains of irregular-shaped yeast cells

fungi plasma membrane

ergesterol

dimorphic

fungi that grows as yeast and mold

Phylum Deuteromycota


• Trichophyton, Microsporum, and Epidermophyton

• Tinea/Ringworm (expand circularly)

• secrete keratinase to break down keratin that makes up skin, hair, and nails

• Ex: athlete's foot

• Penicillum

• called imperfect because a sexual reproductive stage has not been observed

characteristics of dimorphic fungi 


• 25 deg. C- room temp, typically grow as MOLD

  • typically found in the environment

• 37 deg. C- body temp, typically grows as YEAST

sexual reproduction of fungi:


1. haploid (+) & haploid (-) -----> plasmogamy (fusion of cytoplasm)

2. Dikaryon (cell with 2 nuclei)-----> karyogamy (fusion of nuclei)

3. Diploid (2n, nuclei combined now)-----> meiosis

4. Sporangium (stores haploid spores)-----> spores released (to form new fungi haploid

5. mitosis, repeat steps again

worms

helminths

digestive system

target of worms

flatworms

platyhelminthes

• cestodes (tapeworms (NEED TO KNOW))

• trematodes (flukes (NEED TO KNOW), leaf)

cestodes

• tapeworms- are segmented

• scolex- hold fast (attachment) structure to the intestines

• Ex: Taenia- causes taeniasis (GI distress; extreme cases of cyticercosi- seizures)

trematodes

• flukes (not segmented)

• leaf

• ex: Fasciola hepatic (causes fascioliasis- bile duct/liver infection)

roundworms

nematodes

• trichinella

• hookworms

• pinworms

Trichinella

causes trichinosis- worms enter into muscle cells

hookworms

ascaris- from contaminated soil. Live in intestine and can cause line rashes

pinworms

Enterobrius vermincularis

itchy butt, scotch tape

prion diseases

• infectious proteins that are misfolded

• does not contain genetic material

• can cause serous brain and nervous system diseases

Transmissible spongiform encephalopathy 


prion disease

one conformation is misfolded, can be passed on to other prions upon contact

spongiform

tiny holes in the cortex (looks like sponge)

encephalopathy

neurodegenerative disease

Prion protein (PrP)

can fold into any several conformations