Host 3 Parasites

luzuleye's version from 2015-11-28 23:37


Question Answer
Intestinal ProtozoansEntamoeba and Giardia
Entamoeba histolyticafecal oral transmission, cysts are infective (person-person, 90% ppl are asymptomatic cyst passers), intestinal invasion, abcess in liver, dx. w/stool
Giardiafecal oral transmission, cysts acquired from water, NO intestinal invasion but colon is affected instead, bloating/epigastric pain/gas/chronic diarrhea, stool for cysts or trophozites but NO BLOOD OR WBCs
trichomonas vaginalisurethritis, venereal transmission, vaginitis/prostatitis/urethritis, dx. w/trophozoites in discharge/exudate, trophozoite stage only (no cyst)
T. bruceiextracellular, tse tse fly, African sleeping sickness, diffuse meningoencephalitis, dx. w/direct exam of blood, you get a trypanosomal chancre, Winterbottoms sign (org crosses BBB)
West vs. East African sleeping sicknessboth caused by T. brucei, West is subacute and has subtle personality change/coma/death, East is acute and has abrupt fever/HA/occipital lymphadenopathy, Winterbottoms sign
Winterbottoms signT. brucei invades BBB and you get posterior nuchal lymphadenopathy, East African sleeping sickness
FlagellatesTrypanosoma spp. (brucei/cruzi) and Leishmania spp.
Blood/tissue protozoaFlagellates (trypanosoma and leishmania) and sporozoans (plasmodium)
T. cruzireduvvid bug is vector, all nucleated cells, chagas disease, chronic periorbital edema, South/Central America, lives in thatched huts, fecal material of insect makes you sick, preferential infxn of cardiac/gi cells-->megaorgan syndromes Romana's sign, dx. w/serology
Leishmania sp.sandfly, macrophages, south america, can spread to BM-->pancytopenia, lots of soldiers get cutaneous lesions
Romana's signT. cruzi characteristic, unlateral edema at bite site
Megaorgan syndrome possible?T. cruzi (infects cardiac/GI cells), megaesophagus/megacolon, cardiomegaly/fibrosis of heart from too much inflammation, also entamoeba histolytica
Leishmaniasissimple cutaneous, diffused cutaneous, mucocut., visceral, deposit into macros which are overburdened and spill out into the tissues-->more macros infected
Parasitesprotozoans (intestinal and blood/tissue) and multicellular worms (roundworms and flatworms (flukes/tape))


Question Answer
Malaria vectoranopheles mosquito, species is plasmodium
Malarialiver vs. RBC stage, resistance to drug chloroquine, diff species- P. vivax/ovale/malariae/falciparum, immunity to recurrent disease, dx. by blood smear
P. vivax and ovalerelapsing malaria-->cryptogenic disease in liver continually unless treated, invades only reticulocytes
P. falciparummedical emergency, cerebral malaria, invades ALL erythros, blackwater fever (massive hemolysis), no relapse, high morbidity
Malaria complicationsanemia, hypoglycemia, splenomegaly, splenic rupture
P. malariaeimmune complex disease-->renal failure, invades only mature erythrocytes, can be mildly symptomatic for decades


Question Answer
Flatwormsparasitic helminths, categories are trematodes (blood flukes/tissue flukes) and cestodes (tapeworms)
Flukestype of flatworm, leaflike w/2 suckers, hermaphrodites, blood/liver/lung/intestinal, each have snail intermediate host
Schistomiasisblood flukes, common in rural setting, found in US also, S. mansoni/japonicum/haematobium
S. mansoniblood fluke found in inferior mesenteric venules, GI sxs. including mild diarrhea initally then hepatosplenomegaly, portal HTN, spiny egg w/lateral location
S. japonicumblook fluke found in superior mesenteric venules, GI sxs. including mild diarrhea initally then hepatosplenomegaly, portal HTN, small and round egg with lateral location
S. haematobiumblood fluke found in venules of bladder, can cause renal failure/bladder cancer, spiny egg w/terminal location
Schistosomal lifecyclecercariae bind to skin and invade, then goes to circulatory system, lots of eggs spewed out from venous plexuses which lodge in tissues and sxs. arise from robust inflamm. response to eggs, eggs go to feces-->water, miracidia are then taken up by snails-->mature to cercariae
Swimmer's itchcercarial dermatitis, caused by schistomiasis
Complications of schistosomacongestive liver (occluded vessels) so collaterals form, half eggs released in feces/urine and half eggs deposit and cause granulomatous inflamm. response
Fasciolopsis Buskiintestinal fluke, from plants in Far East/Southeast Asia, intermediate hosts are snail/freshwater plants epigastric pain/nausea/diarrhea, dx. w/eggs in feces
Katayma feveracute schistomiasis, 4-6 wks after heavy primary infxn, due to release of egg Ag
Pargonimus westermanilung fluke, from crustaceans, fatter egg
Chlonorchis sinensisChinese liver fluke, from uncooked fish., life cycle includes 2 intermediate hosts (snail/freshwater fish), acute is fever/hepatomegaly, chronic is ab pain/fever, can cause liver fibrosis, predominant notches
Paragonimus westermanilung fluke, Far east, W Africa, Mexico, Peru, snails and crustaceans are intermediate hosts, acute is eosinophilic inflamm. rxn/fever/cough/bloody diarrhea, chronic is pneumonia/lung abcess, dx. w/eggs in feces/pleural fluid
Tissue flukesClonorchis sinensis, fasciolopsis buski, paragonimus westermani
Fluke dx.either biopsy affected organ or look at eggs of fluke

Tapeworms & Nematodes

Question Answer
Tapewormslargest of intestinal parasites, no body cavity, segmented, proglottids are at neck and each is hermaphroditic reproductive unit, older proglottids go posteriorly and drop off releasing eggs, operculated/or nonoperculated eggs, detect eggs in stool
Diphyllobothrium latumbroad fish tapeworm, freshwater, megaloblastic anemia, absorbs B12 in small intestine, oval egg/operculated in feces
Taenia saginatabeef tapeworm, worldwide distribution, no extra intestinal sxs., dull colicky ab pain, 4 suckers, round and nonoperculated eggs
Taenia soliumpig tapeworm, invades GI lining and can go other places, dermal/brain cysticercosis, can cause CNS seizures/focal deficits, round and nonoperculated eggs
Echinococcusdog tapeworm sheds eggs, dog is definitive host, human is intermediate, Cystic hydatid disease, we ingest accidentally go to GI tract and then other places, large membrane-bound cysts with fluid in different locations (hydatid cyst in spinal cord), cysts can rupture and cause anaphylactic rxn, short w/head and 3 perglottids, dx. w/detection of cysts on xray/ct
Hydatid sandeach can give rise to new eggs so need to be very careful during surgery, characteristic of echinococcus
Enterobius (pinworm)ingest eggs from feces, go to GI then adult worms live in terminal large intestine, crawl out thru rectum and lay eggs around anus, dx. using scotch tape test to look at eggs under microscope
Trichuris (whipworm)exist in GI tract and embed in large intestine, can cause prolapsed rectum, malnutrition, egg is barrel-shaped w/mucoid plug
Ascariasislargest intestinal nematode, ingest eggs, invade to vascular system and can invade into alveoli of lungs-->sputum coughed up and swallowed back to intestinal tract, Loefflers syndrome -infiltration of lungs/cough/fever/dyspnea
Hookwormintestinal nematode, penetrates skin-->circulatory system, can go thru lungs-->GI tract, bite can cause slow-leak of blood and thus iron deficiency anemia, pot belly/crave soil/wood, larval penetration causes SEVERE itching, thin walled multicell egg
Strongyloidasiscommon in immunocomp. pxs., in soil/wet grass, larva in sputum of heavily infected px. which is then swallowed--> GI tract, rash and eosinophilia, worldwide distribution
tissue nematode lifecycleinsect transmitted organisms, bite infects tissue, circulates, immature form can collect in lymphatics (usually inguinal) and cause obstruction-->elephantiasis

Tapeworms & Nematodes 2

Question Answer
Filarial wormsparasitic nematodes, adults reside in skin or lymph filariasis caused by wuchereria/brugia/loa loa/onchocerca
Trichenellauncooked pork, orgs exit cyst and invade organs of body, nonspecific myalgias depending on parasitic load, orbital edema, usual sxs are muscle pain/HA/weakness, dx. w/biopsy
Toxocaratissue parasites from dogs/cats, eggs from feces germinate in GI and deposit in organs-->local sxs, persistent hypereosinophilia, dx. w/biopsy or Ab testing
Ancylostoma braziliensescutaneous larva migrans, usually in infants, fungal skin disease
Intestinal nematodesenterobius, trichuris, ascaris, hookworms, trichinella, strongyloides
Blood/lymph nematodesWuchereria bancrofti, brugia malayi, loa loa, onchocerca volvulus
Wuchereria bancrofti and Brugia malayifilarial worms, cause elephantiasis, mosquito is vector, sheathed microfilariae in blood
Loa loaCalabar swelling (subcut. edema), horsefly is vector, sheathed microfilariae in blood
Onchocerca volvulusRiver blindness, vector is blackfly, ocular sxs. (microfilariae in eye)
Visceral larva migranstoxocariasis, worldwide, dogs/cats, persistent hypereosinophilia
Cutaneous larva migranscreeping eruption follows larva migration in skin, ancylostoma braziliense (cat/dog hookworm), direct skin penetration