Protozoan Parasites

groups of parasites

-protozoa

-heminths

unicellular parasites

protozoa

multicellular worm parasites

helminths

acellular parasites

viruses

algae

photoautotrophic protists

fungus-like protists

slime molds and water molds

disease caused by algae

1. red tide - irritation skin and lungs

2. paralytic shellfish poisoning

red tide & paralytic shellfish poisoning

caused by dinoflagellate (algae) NEUROTOXIN - brevetoxin

dinoflagellate

algae that cause red tide & paralytic shellfish poisoning

characteristics of protists

1. unicellular eukaryote

2. ingestive heterotrophic

3. NO cellulose or chitin cell walls in active stage

habitat of protists

-MOST aquatic

-also soil or on plants & animals

roles of protozoa

1. decomposers

2. parasitic

3. zooplankton

zooplankton

-Tiny floating organisms that are either small animals or protozoa

-important part of food chain

phytoplankton

photosynthetic algae found near the surface of the ocean

trophozoite stage

active, motile, feeding stage of protozoa

cyst stage

-dormant or resting form of protozoa

-for survival in harsh environment

cyst stage

often infective or transferrred stage

schizogony (multiple fission)

-asexual reproduction in some protozoans

-multiple nuclear divisions before cytokinesis

definitive

host in which the sexual reproduction of a parasite takes place

intermediate

host for immature or developmental stages of a parasite

-asexual or no reproduction

vector

agent carries & transmits infectious parasite into another living organism

vector

arthropods in parasitic life cycles are often these

transmission protozoan GI diseases

-fecal-oral route

-vehicle: water or food

symptoms protozoan GI diseases

-indigestion to dysentery

-acute or chronic diarrhea

acute diarrhea

3 or more loose stools in a 24-hour period

chronic diarrhea

longer than 14 days/2 weeks

dysentery

pus/blood filled diarrhea

treatment GI protozoans

-oral rehydration therapy

-antimicrobial medications

prevention GI diseases

•Water hygiene - boiling, filtering, disinfecting

•Personal hygiene

•Proper food preparation

examples protozoan GI diseases

1. giardiasis

2. amoebiasis/amoebic dysentery

3. crypto - cryptosporidiosis

4. cyclosporiasis

Giardia duodenale or lamblia

causative agent of #1 parasitic infection in the U.S.

giardiasis

caused by spread of cysts in water

-chronic diarrhea

-hikers

-can infect dogs

-person to person - seen in daycares

cryptosporidiosis "crypto"

-acute diarrhea

-usually transmitted by water/some food

-swimming pools & water supply

-oocysts resistant to chlorine

-fatal in AIDS patients

cyclosporiasis

chronic diarrhea caues by Cyclospora cayetanensis

cyclosporiasis

-usually caused by ingesting oocysts on produce

-outbreaks from raspberries, greens & herbs

-NO PERSON TO PERSON transmission

-humans only known host

giardiasis

chronic diarrhea caused by a flagellated protozoan

Only GI protizoan disease NOT person to person

cyclosporiasis - oocysts not infective right away

GI protozoan disease associated with municipal water supply outbreak

cryptosporiasis

amoebic dysentery/amoebiasis

disease caused by Entamoeba histolytica

3 GI diseases with hardy survival cysts & low ID

giardiasis & amoebic dysentery & crypto

invasive GI protozoan that causes extra-intestinal absesses

Entamoeba histolytica - amoebic dysentery

amoebic dysentery/amoebiasis

-disease with carriers

-most deaths from GI protist

-In U.S. high in MSM populations & immigrants from endemic regions

-high in LMICs with poor sanitation

African sleeping sickness/trypanosomiasis

CNS protozoan infection caused by Trypanosoma brucei

Almost erradicated

protozoan CNS diseases

-rare

-difficult to treat

-usually fatal

protozoan CNS diseases

-African sleeping sickness

-Toxoplasmosis

-PAM primary amoebic meningoencephalitis

African sleeping sickness/trypanosomiasis

-disease with vector: tsetse fly

-reservoir: game animals of Sub-Sahara

-loss of interest, sleepiness, coma, death

Naegleria fowleri

brain eating amoeba enters with water through nose

deadly!

Naegleria fowleri

causative agent PAM (primary amoebic meningoencephalitis)

Toxoplasma gondii

causative agent of toxoplasmosis

Toxoplasma gondii

-vertical transfer of this protozoan: mom to fetus - congenital

-miscarriage or still birth

Toxoplasmosis

-ingestion of oocyst from cat feces or tissue cysts in raw meat

-asymptomatic in healthy people

-latent - causes encephalitis in immunocompromised

-#1 leading cause of death from foodborne illness

cats

definitive host of Toxoplasma gondii

humans & every other warm blooded creature

intermediate hosts of Toxoplasmosis gondii

Plasmodium species

causative agent of malaria

#1 global killer

malaria

vector & definitive host: Anopheles mosquito

Plasmodium species

causes recurrent cycles of paroxysmal fever, intense chills, sweat & anemia

~every 48 hours

Trichomonas vaginalis

flagellate protozoan that causes #1 non-viral STI

Trichomonas vaginalis

-causative agent vaginitis - frothy odorous green discharge

-urethritis - painful urination - dysuria

trichomoniasis

-STI mostly asymptomatic in men

-passed back and forth through sexual contact

trichomoniasis

-parasitic infection with no cyst stage - transfered only thru intimate contact

-verticle transmission-mother to fetus

-preterm birth & neo-natal pneumonia

3 stages of plasmodium life cycle

-liver stage (human)

-blood - RBC stage (human)

-mosquito stage - sexual reproduction

cryptosporidiosis "crypto"

#1 water borne disease in U.S.

Chagas' Disease

-caused by Trypanosoma cruzi

-flagellated protozoan

-Central America and parts of South America.

-vector: triatomine ("kissing bug")

-heart damage & gastrointestinal tract complications

American Trypanosomiasis

Chagas disease

-neglected parastic disease CDC

Balantidium coli

only ciliate that parasitizes humans and causes dysentery

Balantidium coli

causes balantidiasis

associated with pigs

Apicomlexans

phylum of non-motile obligate intracellular protozoans

Chagas disease, toxoplasmosis & trichomoniasis

vertically transmitted protozoan diseases

Hitchhiker's disease or Beaver Fever

giardiasis

eye protzoal disease

keratitis caused by Acanthamoeba keratitis