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What is a parasite?
A person who received free meals in return for amusing or impudent conversation
How are parasites classified?
- By how they move, protoza or metazoa
What is a metazoa?
- -multiple cells
- Examples: Helminths -worms (Tramatodes, Nematodes, Cestodes)
- Arthropod Vectors (External)- Arachnids, insects
What are protozoas?
- -Single cell
- Ciliats, Amoebae, Flagellates, Apicomplexans
What are the routes of infection?
- -Penetration of the eyes- Acanthamoeba
- -Vector-borne-Tsetse fly, mosquito, arachnids
- -Sexual contact-Entamoeba, giardia, trichomonas
- -Inhalation-Acanthamoeba, Naegleria
- -Fecal (oral, ingestion)-Ascaris, cryptosporidium, cyclospora, entamoeba, enterobius, giardia, taenia, toxoplasma
What are amoebae?
- -No defined shape-pseudopodia
- -most are free-living
- Examples: Acanthamoeba sps, Entamoeba histolytica
What is entamoeba histolytica?
- -Human carrier only
- Transmission: Ingestion, sexual
- 1. Luminal Amebiasis (Most asymptomatic)
- -dysentery (painful bloodly diarrhea), mucus, no fever or vomiting, teardrop ulcer in the colon.
- 2. Invasive Extraintestinal Amebiasis: Necrotic lesions at site, liver abscesses
What is naegleria fowleri?
- -Free living not obligate parasite
- -Direct infection through the nostrils
- -Inhalation: swimmers
- -Primary Amebic Meningoencephalitis (PAM), changes taste/smell, vominting, nausea, fever, headache, rapid onset of coma, and death in two weeks.
What are flagellates?
- -locomote by single long flagellum
- Examples: Trypanosoma, Giardia, adn Trichomonas
Wat is Trypanosoma Brucei?
- -Cattle and wild animal resovoirs
- -Vector Borne: Tsetse Fly
- -African sleeping sickness, necrotic lesion, fever (every 7-10 days), swollen lymph node, meningoencephalitis, headache, extreme drowsiness, coma, and death
- -Very toxic treatment
What is Trypanosoma Cruzi?
- -chaga's disease
- Swelling at bite, feverl, swollen lymph nodes, CHF
- Vector: Kissing Bug Feces
What is Giardia intestinalis/lamblia?
- -Giardiasis (Diarrhea) Bever fever
- -pale loose, foul smelling fatty stools, fatulence, weight loss, ab pain, predisposition in immunosuppressed, homosexuals, sewage workers
- -Distrubution is untreated water
What is Trichomonas vaginalis?
- -Most common protozoan disease, 3 billion at risk
- -Dwells in vulvas, vaginas, urethras and prostates of humans only
- -Mosty asymptomatic in men
- -Vaginitis in some women: odorous discharge, ab pain, dyspareunia, dysuria
What is Leishmania sps?
- -Vector: female sandfuly
- -Animal Host
- -Infect and destroy macrophages
- -Cutaneous problems- like boils, painful skin sores
What are apicomplexas?
- -Used to be called sporoza
- -Complicated life cycles with at least two different hosts
- -Examples: Plasmodium, toxoplasma
What is the plasmodium sps?
- -Vector borne: female anophelse sps mosquite
- 4 Species: P. Falciparum, vivax, ovale, malariae
- -Over 400 million infection
- 3 stages:
- -Liver: Vivax and Ovale remain dorman here for years, recurring
- -Blood Cycle: feed on RBC, fever on cell rupture
- -Mosquito cycle: ingest sexually active form from RBC, which mature in the gut
- Symptoms: Recurrent fever, chills, diarrhea, headache, hemolytic anermia, jaundice
What is P.falciparum?
- -Worst type of malaria
- Black water fever: extreme cell lysis, dark urine and kidney failure
- Cerebral malaria: hemorrhage in teh brain from inelastic RBC
What are protective conditions of malaria?
- Sickle cell trait- sickling RBC resist penetration
- Hemoglobin C- mishapen RBC resist penetration
- -Glucose 6 phosphate dehydrogenase deficieny-needed for parasite DNA synthese
- -Lack of duffy antigens- resistance to P. vivax
What is toxoplasma gondii?
- -About 40% of US population is exposed
- -Animal host-cat
- -Fecal-oral transmission, inhalation
- -Selfl limiting except in fetus and AIDS patients
- -Asympathetic, spastic paralysis, blindness, brain infection
What are intermediate hosts and definitive host?
- Intermediate: Larval/ immature form
- Definitive: adult forms, large # of eggs
What is W.bancrofti?
- -Vector borne-transmitted by female mosquitoes
- -Infests sub Q tissue and lymphatics causing filariasis
- -Can result in elephantiasis,which is not reversible
- -Secondary bacterial infections
What is Ascaris lumbricodies?
- -Most common ringworm
- Largest nematode
- -Fecal oral route: egg, intestine, larvae, lung, larvae 2, intestine, adult
- -Fever, dry cough, ab pain, obstruction, eosinophilia, nausea, vomiting, asthma, worm emigrations,no diarrhea
What is enterobius vermicularis?
- Worldwide, most common worm in US
- -Itchy bottom, tape test
- Fecal oral colon: nocturnal laying of eggs
What are cestodes?
- -Flat, segmented, ong intestingal parasites
- -Scolex for attachment, cuticle
- -Multiple hosts, humans are definitive host
- -Fecal oral transmisison
- Taenia saginate: beef tapeworm
- Taenia Solium: pork tapeworm
- Asymptomatic, nausea, ab pain, diarrhea, blockage, neurolgocial and ocualr symptoms by T. solium larvae