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79 Cards in this Set
- Front
- Back
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Parasitology
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the study of eukaryotic parasites (protozoa and helminths)
20% of all infectious diseases |
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macroparasites- helminthes
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microparasites- bacteria and viruses
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Protozoa
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single celled, animal-like microbes, usually have some form of motility
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4 groups of protozoa
-25 are parasitic to humans |
1)sarcodinians (amoebas w/ pseudopods)
2) ciliaites 3)flagellates 4)apicomplexans- no movement |
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trophozoite- active feeding cell
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cyst- survive in unfavorable environments
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Amoebas
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aqueous habitat
Entamoeba histolytica alternates btw trophozoit and cyst pseudopod during trophozoite stage cyst has chromatoidals- clusters of ribosomes |
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Enatmoeba histolytic
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thru food or drink contaminated, intestine, tropical areas,
if untreated, affects cecum, appendix, colon and rectum ulcerations, dysentery, and tumor like growths (amoebas). not killed by chlorination |
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Amebic infections of the brian
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Naegleria fowleri and Acanthamoeba sp.
standing water or brackish water. |
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Naegleri fowleri-
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enters nasal mucosa
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Acanthamoeba
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enters broken skin, conjunctive or lungs or urogenital
enters eye |
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Ciliates- Balantidium coli
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aquatic habitats, only ciliate that affects humans
contaminated water and food, stomach and small intestine. from pig intestine (also sheep, cattle, and horses) |
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2 Important Flagellates (Mastigophorans)
(that don't live in blood) |
1) Trichomonas
2) Giardia Hemoflagellate- all other flagellates live in blood |
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Trichomonas - (a flagellates/mastigophoran)
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4 anterior flagella
3 speciecs harmful to humans (vaginalis, tenax and hominis STD: trichomaniasis |
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Giardia intestinalis
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seen by Antonie von Leeuwenhoek in his own feces
heart shape, 4 pairs of flagella from containated water or food. hikers from mountain water sources, in daycares, senior centers, look for cysts in feces |
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Hemoflagellates:
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vector borne blood parasites
live in blood and tissues of human |
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Hemoflagellates
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Trypanosoma and Leishmania are important
obligate parasites, spread by blood-sucking insects, tropical regions, complicated life cycles, |
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4 developmental stages of hemoflagellates
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1)amastigote- no flagella
2) promastigote- 1 single, free flagella 3)epimastigote- has flagella and undulated memebrane 4)trpsomastigote- large fully formed state |
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Trypanosome -
biphasic lifestyle |
2 important species:
1) Teypanosoma brucei-African sleeping 2) Trypanosoma cruzi- Chagas Dieases |
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biphasic lifestyle
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alternates between vertebrate and insect host
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Trypanosoma brucei (AFRICAN SLEEPING SICKNESS)
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spread by tsete flies, reservoir is mammalian host, flies spreads trypanosome into blood,
damages spleen, lymph nodes and brian sleep disturbances, tremors and paralysis, and coma |
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Trypanosom cruizi (CHAGAS DIEASES)
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Latin America
reduviid (kissing bug) bites corner of mouth or eye and discharge its feces chronic inflammation of organs (heart and brain) |
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Leishmania
(Kala azar is severe an fatal form) |
zoonosis (affects animals but can affect humans -rabies)
transmitted by female phlebotomine flies (sand flies) infected macrophages carry pathogen into the skin and bloodstream fever, enlarged organs, anemia |
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Apicomplexan Parasites
(aka SPOROZOANS) |
no movement, complex life cycles, alternate between sexual and asexual phases
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3 important apicomplexans to humans
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1) Plasmodium (malaria)
2) Toxoplasma (toxoplasmosis) 3) Cryptosporidium (crpytosporidosis) |
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Plasmodium (Malaria)
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has 4 species
P. malariae, P vivas, P falciparum, P. ovale humans and primates **all forms spread by female ANOPHELES mosquito. (also by needles, blood transfusions, mother to fetus) |
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300 million to 500 million new cases each year!
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90% of them in Africa
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2 stages for life cycle of Anopheles mosquito (carries plasmodium - malaria)
1) asexual in humans 2) sexual in mosuito |
1) asexual- in humans, cells called sporozoites
sporozoites divide (schizongy) and creates many daughter parasites (merozoites) then merozoite invade red blood cells |
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Sporogony
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sexual stage when mosquito drakes infected RBC into ther stomach, and fertilizations occurs to infect the next host.
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symptoms of malaria
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chills, fever, sweating, anemia, organ enlargement
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to reduce infect
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use bed nets, reprellents, screens, insecticides,
stay inside at night take weekly doses of prophylactic drugs |
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2nd important apicomplexan: Toxoplasma gondii
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in cats, harbors oocysts in GI tract
by ingesting raw or rare meats with cysts, or from contact with cat feces infection is mild and flu-like |
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3rd imporatnt apicomplexan: Cryptosporidium
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vertebrate pathogen, in tissue and oocyst phase,
handling animals or drinking contaminated water, intestinal/enteric symptoms- |
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Coccicidan Parasites-
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still apicomplexian parasites
zoonoses (infection in animals but can be transmitted to humans) both thru oral-fecal contamination ex. Cystoispora and Cyclospora and Babesia |
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Babesia
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first protozoan found to be responsible for dieases (redwater fever)
cattle, can affect humans by ticks |
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Helminthes
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invertebrate worms
2 Phyla: 1) Aschelminthes- nematodes/roundworms 2)Platyhelminthes (flat worms, thin, flattened body) either Trematodes- flukes (ovoid, compact body) or Cestodes-tapeworms (segmented bodies) |
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LIfe cycle of helminthes
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fertilized egg (embryo)- in environment
larval-in intermediate host adult-in final (definitive) host |
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Phylum Aschelminthes
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Roundworms/nemators
separate sexes |
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Phylum Platyhelminthes
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Cestodes- tapeworms, hermphrodites
Trematodes- flukes, separate sexes an hermaprodites |
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transmisttion
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involves eggs, larvae, and insect vectors
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Worm's adaptations for parastic habitat
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specialized mouthparts, enzymes to liquify and penetrate tissues, cuticle or outer covereing to protect agasint host defenses
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Helminth final residence
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intestinal musose, blood vessels, sympathies, tissue, skin, liver, lungs, muscles, brain, eyes
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Leukocytes
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eosinophiles-specilized leukocytes to combat worms
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Nematodes (roundworms)
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protective cuticles, circular muscles, complete digestive tract****, separate sexes and well-developed reproductive tracts
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Ascaris lumbricoides (nematodes)
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giant intestinal worm, eggs spread thru feces,
*****greatest number of of worm infections |
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Trichuris trichiura and Whipworm infection
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topic and subtropics, fecal contamination, eggs develop in soil, stay in intestine
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Enterobius vermicularis
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pinworm/seatworm
most common worm dieases in children lodge under fingernails small intestine self-inoculation in common |
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Nematodes: hookworms
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Necator americanus and Ancylostoma duodenale
spread thru human feces |
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Strongyloides sercoralies
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threadworm
minute size, can complete life cycle inside or outside body larvae penetrate skin, and migrate to lungs |
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Trichinella spiralis and Trichinellosis
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entire life cycle inside mammalian host
undercooked or raw pork or bear meat humans are dead-end hosts (only spread thru cannibalism) |
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Tissue Nematodes:
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filarial worms-thin filamentous bodies
complete life cycle ein blood, lymph or skin spread by biting arthropods, cause chronic, deforming disease |
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Review: 2 types of nematodes
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1) Intestinal =complete life cycle in intestines
2) Tissue = complete life cycle inhuman blood, lymph, or skin (filarial worms) |
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Wuchereria bancrofi (a type of filariam nematod affects tissue)
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causes bancrofitian filariasis
tropic, spread by flies deposit larvae into lymph elephantistis, |
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Onchocera volvulus-(a type of filariam nematod affects tissue)
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river blindness, an African ideas,
small river insects larvae destroy cornea of the eye |
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Loa Loa (a type of filariam nematod affects tissue)
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the African Eye Worm
spread by the dipteran flies, enters skin and may spread to the eye |
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Dracunculus medinensis (a type of filariam nematod affects tissue)
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guinea worm, INdia, Middle East, Cental African
parasite is Cyclops |
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Flatworms:
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Trematodes (flukes) and Cestodes (tapeworms)
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Trematodes
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have leaflikes bodies with suckers,
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Trematodes: Schistosoma (blood flukes)
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Schistosoma (blood flukes)
tropical disease, early/first larva called miracicidum (in snails) second larva called cercaria enters humans, matures in liver, sheds eggs in intestine or bladder |
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Trematodes: Opisthorchis (Chinese liver fluke)
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zoonostic,
lives in mammals, snails and fish. Humans each fish infected with larvae. Affect human lier |
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Trematodes: Fasciola hepatic (liver fluke)
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sheep, cattle, goats, sometimes humans.
humans affected when eat raw aquatic plans fluke lodges in lier |
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Trematodes: Paragoniumus westermani (lung fluke)
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Asia, India, South America, pulmonary tissues.
Humans eat undercooked crustaceans worms migrate to lungs |
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Cestodes: Tapeworms
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long, very thin, ribbonlike bodies
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Cestodes body
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scolex- head to anchor worm
Strobila- long ribbon like body Proglottids- individual body segments. each proglottids can absorb food and release eggs |
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Cestodes: Taenia saginata (beef tapeworm)
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animals infected when grazing on land with human feces. humans ingest larval form (cysticercus)
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Cestodes: Taenia solum- (pork tapeworm)
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infect humans thru csticerci or ingesting eggs or drink
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Arthropods
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phlum invertbrates, shared body plan, with an exoskeleton and jointed legs
insects, arachnids and crustaceans biological vectors |
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Common arthropod vectors
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1) moquitoes
2) fleas 3) lice 4) ticks |
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Mosquitoes
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class Diptera
lay eggs in aquatic habits only females take blood from humans to complete egg production **transmit malarai |
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Fleas
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tiny, highly motile, feed on warm-bodied animals
mainly carry zoonotic diseases (infect non-humans but humans get infected thru eating them) |
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Lice
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small soft, attach to head and body hair, suck blood and release feces into wound.
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Flies
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tsetse flie spreads African Sleepness and Chagas diease (trypanosomiasis
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Ticks
2 types: hard (ixodid)-rickettsial, borrelial, viral soft (argasid)- fever |
arachnids
larvae, nymph and adults feed by sucking flood |
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All protozoan pathogens have a
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trophozoite stage
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Entamoeba histolytica
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amoeba infects small intestines
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Giardia
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flagellate, large intestine
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Plasmodium (malarai)
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sexually in the - mosquito
asexually in the - human |
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Life cycle of Plasmodium
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1) asexual phase- in humans
2) exoerthrocytic phase- sporozoites invade cells of the liver, under go division to create many merozoites 3) erthrocytic phase- merozoites enter blood and invade RBC 4) Gametocyte phase- some of RBC enter sexual cycle, when another mosquito bites, it gets these infected blood 5) sexual phase- occurs in mosquito, produces infectious sporozoite |
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Oocyst found in feces
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pseudocyst in tissue
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Antihelminthis medications work by
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paralyzing the worm and distrupting the worms metabolism
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