CUTANEOUS FUNGI:



FUNGI:

(cell wall: chitin (cell membrane: sterols (ie. ergosterol) (favored by heat and humidity

|YEASTS |MOLDS |

|single cells (oval or round) |long filaments or hyphae (septate or nonseptate) |

|asexual budding |asexual spores (conidia) |

|pseudohyphae (clusters of buds) |mycelia (segments of hyphae) |

|humans |environment (ie. soil) |

|grows on 37(C (blood agar, humans) |grows on 25( (Sabouraud’s agar) |

CUTANEOUS FUNGI:

|ORGANISM |PATHOGENESIS / CLINICAL FEATURES |DIAGNOSIS / TREATMENT |

|Superficial fungal infections (dead skin): |(cause pigment changes on surface of skin |(skin scrapings w/ KOH prep |

| |(lesions contain budding yeast cells and hyphae |(selenium dandruff shampoo (topical imidazole |

|Pityriasis (Tinea) versicolor (multi-colored) |(hypopigmented patches on the skin, especially on tanned skin in the summer (( with hot, humid |(topical miconazole for Tinea versicolor |

|(Malassezia furfur |weather); scaling, itching | |

|Tinea nigra (black-colored) |(dark brown to black painless patches on palms and soles |(keratolytic agent: salicylic acid for Tinea nigra |

|(Cladosporium (Exophiala) werneckii |(found in soil and transmitted during injury (southern states) | |

| | | |

|Dermatophytes: |(direct contact (fomites |(skin scrapings w/ 10% KOH on glass slide shows |

|(no yeast form | |hyphae |

|(affect superficial keratinized structures (scaly skin, hair |(animals: Microsporum also spread from dogs, cats |(macronidia or microconidia |

|loss, and brittle nails) through action of keratinase |(”Dermatophytid” reactions: hypersensitivity to fungal antigens | |

|(pruritic papules, vesicles |( no organisms found in granulomas |(ecothrix: hyphae around hair shaft |

|(Microsporum (spiky, spindle-shaped, thick-walled, single) | |(endothrix: hyphae w/in hair shaft |

|(Trichophyton (cylindral, smooth, thin-walled, single) |(tinea capitis: scaly calp, hair loss (T. tonsurans, T. rubrum) | |

|(Epidermophyton (club-shaped, smooth moderately thick-walled,|(tinea corporis: ringworm of glabrous/smooth skin( red, raised |(Wood’s light: fluorescence when tinea capitis |

|clusters of 2-3) |(tinea cruris (jock itch): red itchy patches on groin, scrotum |lesions caused by Microsporum placed in UV light |

| |(tinea pedis (athlete’s foot): toes(cracking, peeling of skin |(topical imidazole |

| |(tinea unguium (“onchomycosis”): thickened, discolored, brittle nails |(oral griseolfulvin (hair, nails) |

| |(tinea barbae: patches along beard distribution | |

|Subcutaneous Mycoses: |(grow in soil, vegetation( infect during trauma | |

|Sporotrichosis: Sporotrix schenckii |(subcutaneous nodule: local pustule or ulcer that spreads along lymphatics( more necrotic nodules|(cigar-shaped budding yeasts |

|(dimorphic fungi in soil, plants (rose thorns, splinters)( |along linear, lymphatic distribution |(branching hyphae w/ oval conidia at tips( “daisy |

|enters via trauma | |petals” |

| | |(oral KI |

| | |(itraconazole or amphotericin B |

|Chromoblastomycosis |(slowly progessive granulomatous infection through skin trauma |(copper-colored sclerotic bodies: dark brown, funus |

|(Phialophora, Cladosporium) |(cauliflower warts w/ crusting abscess along lymphatics: initially, one violet-colored wartlike |in WBC’s, M( |

|(soil fungi in tropics: bare feet and legs |lesion( more nodules over months/years |(local excision/ itraconazole |

|Mycetoma (Petriellidium, Madurella) |(abscesses, with pus discharged through sinuses (pus has compact colored granules( similar to |(sulfonamides: actinomycotic form |

|(wounds on feet, hands, or back |Actinomyces, Nocardia lesions |(no treatment for fungal form |

SYSTEMIC FUNGI:

(within lungs( differentiate into yeasts (mostly asymptomatic or mild pneumonia (not contagious from person to person

(itraconazole for lung disease (amphotericin B for severe , disseminated disease

|Coccidiodes immitis |(in soil, it forms hyphae with alternating arthrospores and empty cells( inhalation of |(tissue: spherules w/ doubly refractive walls filled|

|(dimorphic (mold, spherule w/ endospores) |arthrospores by humans |w/ endospores |

|(soil of arid regions: southwestern USA, Latin America (Arizona, | | |

|New Mexico, southern CA) |(dissemination in IC: meningitis; bone and skin granulomas |(skin tests (spherulin or cocciodin)( DTH rxn |

|(Filipinos |(erythema nodosum (red tender nodules on extensor surfaces) and arthralgia( “valley fever” |(IgM/ IgG precipitin test |

|(2nd most common opportunistic infection in AIDS patients |(San Joaquin Valley, CA.) or “desert rheumatism” (Arizona) | |

|Histoplasma capsulatum (nonencapsulated) |(2 types of asexual spores: tuberculate macroconidia (thick walled w/ fingerlike |(tissue: oval budding yeast cells found in M( |

|(dimorphic (mold, yeast) |projections( lab ID) and inhaled, infectious microconidia (smaller, thin, smooth-walled |(skin tests (histoplasmin) |

|(faculatative intracellular parasite |spores) |( DTH rxn |

|(soil w/ bird droppings (ie. Starlings, bats) |(calcification of small granulomatous foci in lungs/ spleen |(complement fixation |

|(Ohio, Mississippi River Valleys |(AIDS pts: liver, spleen, and lymph nodes: hepatosplenomegaly |(chest X-ray ((TB) |

|Blastomyces dermatitidis |(inhaled ovid conidia |(tissue: thin-walled round yeast cells w/ single |

|(dimorphic (mold, yeast) |(also infects other animals (dogs) |broad-based buds and doubly refractive walls |

|(moist soil rich in organic material |(rarest systemic fungal infection( but also most severe and rarely asymptomatic | |

|(North America (east of Mississippi) and Central America( worldwide|(ulcerated granulomas of skin, bone w/ weight loss, night sweats | |

|Paracoccidiodes brasiliensis |(inhaled spores |(tissue: thick-walled with multiple buds |

|(endemic to rural Latin America | | |

OPPORTUNISTIC FUNGI:

(diabetes, lymphomas, broad spectrum antibiotics, immunosuppression (chemotherapy, AIDS pts)

|Candida albicans |(oral thrush (creamy white patches) |(C. albicans: germ tube test at |

|(oval yeast w/ single bud; blastoconidium |(diaper rash (skin folds: between fingers, groin) |37 (C X 3hrs. and chlamydospores |

|(budding yeast cells and pseudohyphae |(vaginitis: vaginal itching and discharge (( risk during menses and pregnancy, oral |(oral thrush: ”swish and swallow” nystatin |

| |contraceptives, antibiotics, DM, ( pH) |(vaginitis: imidazole suppositories |

|(normal flora of mucous membranes of upper respiratory, GI, and |(IC: esophagitis (substernal chest pain and dysphagia) |(amphotericin B (dissem. disease) |

|female genital tracts |(dissemination (retinal exam shows multiple white fluffy candidal patches)( sign of |(skin test w/ Candida: indicator of competent |

|(normal flora, but never in blood |neutropenia |cellular immunity |

|Cryptococcus neoformans |(inhaled through lungs( mostly asymptomatic |(India ink: halo around organism |

|(oval budding yeast (no mold form) |(meningitis (pneumonia; bone and skin granulomas |(CSF: Ab to capsular antigen |

|(pigeon droppings (eucalyptus tree |(4th cause of death in AIDS pts |(flucytosine or amphotericin B |

|Aspergillus fumigatus( aspergilloma |(dissemination: skin, CNS, heart, lung, nasa-orbital area, cornea |(flat, velvety, bluish-green colony |

|(mold only: septate hyphae( V-shaped | |(fungus ball on chest X-ray |

|(airborne conidia (inhaled, ingested, cut skin) |(AIDS: hemoptysis and granulomas (lung cavitations) |(surgical removal, amphotericin B |

|(A. flavus on rice/grains( mycotoxins (ie. aflatoxin)( toxic or |(allergic bronchopulmonary aspergillosis: type I hypersensitivity reaction (IgE) resembling | |

|carcinogenic to liver( ( hepatocellular carcinoma |asthma | |

|Mucormycosis (Mycor, Rhizopus) |(rhinocerebral mucormycosis: associated with diabetes |(endospores enclosed w/in a sporangium |

|(saprophytic molds only: nonseptate hyphae (root branches) w/ |(infection of nasal mucosa w/ invasion of sinuses and orbit |(surgical resection |

|broad irregular walls and right-angle branches |(molds proliferate in walls of blood vessels (telangiectasia) |(amphotericin B |

PROTOZOANS:

(eukaryotes with endoplasm, ectoplasm, and a cytosome

(definitive host: harbors sexually reproducing stage (intermediate host: harbors asexually reproducing stage

|Intestinal and Urogenital: | | |

|Entamoeba histolytica |(invasion of intestinal epithelium and secrete enzymes( localized necrosis( “teardrop” |(trophozoites w/ RBC in cytoplasm ( active disease |

|(motile amoeba (trophozoite) |ulcer( erode and destroy intestines |(cysts or trophozoites w/o internalized RBC( carrier |

|(ingestion of nonmotile cyst (4 nuclei) |(amoebic dysentery: bloody, mucus-containing diarrhea w/ lower abdominal discomfort, |state |

|(differentiates into trophozoites in the ileum |flatulence, tenesmus, weight loss |(diloxanide furoate to kill cysts |

|(1 cyst=8 trophozoites( colonize colon, cecum |(amoebic abscess of liver: RUQ pain, weight loss, fever, tender, enlarged liver( can |(luminal amebicide) |

|(trophozoites (single nucleus) in diarrheal stool |penetrate diaphragm and cause lung disease |(metronidazole (Flagyl): luminal and systemic |

|(cysts in formed stool |(E. coli: 8 nuclei (E. hartmani: 4 nuclei also, but smaller |amebicide |

|(1-2% of U.S. population (homosexual males) |(E. dispar: nonpathogenetic | |

|Giardia lamblia |(cysts differentiate to trophozoites in duodenum |(filter water: chlorination does not kill; must boil|

|(ingestion of cysts (4 nuclei) |(no invasion: attachment to duodenal wall (surface of villi)( inflammation of mucosa( |and filter |

|(1 cyst = 2 trophozoites (pear-shaped w/ 4 pairs of external |malabsorption of protein, fat |(string test: swallowing string into duodenum( |

|flagella w/ 2 anterior nuclei) |(nonbloody, foul-smelling diarrhea w/ nausea, anorexia, flatulence, and abdominal cramps for|trophozoites adhering |

|(camping, day-care centers, homosexuals |weeks to months; no fever |(metronidazole (Flagyl) |

|Cryptosporidium parvum |(mild diarrhea (attach to jejunum (no invasion) |(acid-fast stain (modified Kinyoun acid-fast stain)( |

|(oocysts release sporozoites, which form trophozoites( ( ( oocysts |(infants and AIDS patients: chronic, watery, nonbloody diarrhea w/ large fluid loss (up to |oocysts in feces |

|passed out in feces |3-17 liters of stool per day)( life-threatening; may also have fever, dehydration, weight |(no effective drugs; purify water |

|(ingested oocysts (4 motile sporozoites) |loss |( try azithromycin |

|Cyclospora cayatanensis |(1996 outbreak from contaminated raspberries |(fluoresce blue under UV light |

|(Cyanobacterium-like body( CLB) |(disease similar to Cryptosporidium (up to 6 weeks) | |

|Isospora belli |(severe diarrhea in immunocompromised (AIDS) patients |(trimethoprim + sulfamethoxazole (Bactrim) |

|(elliptical oocysts w/ 8 sporozoites |(invasion of small intestine mucosa( destruction of brush border) | |

|Microsporidia |(severe, persistent, watery diarrhea in AIDS patients |(albendazole |

|(obligate intracellular replication | |(spores (spiral polar filaments) |

|Balantidium |(diarrhea |(large ciliated trophozoites or large cysts w/ |

|(only ciliated protozoan |(main reservoir are domestic animals like pigs |V-shaped nucleus in stool |

|Trichomonas vaginalis |(watery, foul-smelling, greenish vaginal discharge w/ itching and burning sensation |(pear-shaped motile trophozoites on wet mount of |

|(pear-shaped w/ central nucleus and 4 anterior flagella and |(10% of men have urethritis (most are asymptomatic) |vaginal secretions |

|undulating membrane |(very common cause of vaginitis( may affect pregnancy | |

|(sexual contact (no cysts, only trophozoite) | |(metronidazole for both partners |

|Naegleria fowleri |(meningoencephalitis: just like bacterial meningitis nausea/vomiting, fever, headache, |(( PMN, ( protein, ( glucose |

|(cysts (resistant to chlorine) and trophozoites |stiff neck( 95% die within 1 wk |(amphotericin: poor results |

|Acanthamoeba |(chronic, granulomatous, brain infection in AIDS patients |(( PMN, ( protein, ( glucose |

|(cysts (resistant to chlorine) and trophozoites |(keratitis: inflammation of cornea in contact lens wearers |(amphotericin: poor results |

|Blood and Tissue Protozoa: | | |

|Malaria: |(asexual cycle/schizogony (in humans): sporozoites enter humans during blood meal by |(thick and thin Giemsa stain of blood smears: |

| |mosquito( enter hepatocytes within 30 minutes( differentiate into schizonts( rupture and |presence and ID |

|Plasmodium falciparum (common) |release merozoites into blood( infect RBC’s( differentiate into ring-shaped trophozoites( |(signet-ring trophozoites w/in infected RBC’s |

|Plasmodium malariae (4%) |schizonts (16-32 nuclei)( merozoites |(P. falciparum: crescent-shaped gametocytes |

|Plasmodium vivax (common) |(sexual cycle/sporogony (in mosquitoes): some merozoites develop into male and female |(others: spherical |

|Plasmodium ovale (very rare) |gametocytes (one female macrogamete or 8 sperm-like microgametes)( diploid zygote( |(chloroquine: acute malaria( kills merozoites (in |

|(vector: female Anopheles mosquito |sporozoites( salivary glands |RBC’s) |

|(tropical, subtropical areas | |(primaquine: prevent relapses in P. vivax, P. ovale |

|(300-500 million clinical cases/ year |(abrupt onset of fever/chills, headache, myalgia, arthralgia two weeks after mosquito bite( |by killing hypnozoites |

|(1.5-2.7 million deaths (mostly children) |periodic cycle of chills, fevers, and sweats (coincides w/ cycle between destruction of |(mefloquine or (quinine + Fansidar: sulfadoxine, |

|(blacks w/ sickle cell more immune than whites |RBC’s) |pyrimethamine) for chloroquine-resistant strains of |

|P. vivax, P. ovale, P. falciparum ( 48 hr. cycle |(fever spikes (up to 41( C) w/ splenomegaly, nausea/vomiting, abdominal pain, and drenching |P. falciparum |

|P. malariae( 72 hr. cycle |sweat accompanying fever |(chemoprophylaxis w/ chloroquine, pyrimethamine |

| |(brain/kidney involvement if P. falciparum untreated |bednets |

|(schizogony: nuclear division w/o cell division( merozoites bud |(hemolysis( hemoglobiuria (dark urine = “blackwater fever”) |(avoid stagnant water |

|off from schizonts |(“sticky knobs” adhere and plug up capillaries( brain necrosis | |

|(P. vivax, P. ovale: hypnozoites latent in liver( reactivation | | |

|Toxoplasma gondii |(cell-mediated immunity |(IF assay for IgM antibodies |

|(cat feces w/ cysts (eat undercooked pork |(symptoms may resemble mononucleosis (heterophil-negative) |(crescent-shaped trophozoites in Giemsa stain preps |

|(sexual reproduction in cats |(infection during pregnancy (new infection)( abortion, stillbirth, neonatal disease w/ |(sulfadiazine + pyrimethamine |

|(transplacental transmission (TORCH) |encephalitis, chorioretinitis (blindness), hepatosplenomegaly, fever, intracranial |(pregnant should avoid emptying litter boxes |

|(infect any nucleated cell |calcifications | |

|(most common CNS infection in AIDS patients |(IC: fatal encephalitis (reactivation of dormant cysts) | |

|Pneumocystis carinii (classified as fungus) |(airborne inhalation (no person to person though) |(Giemsa stain of lung smear: trophozoites, |

|(mortality > 80% if untreated, (50% if treated |(sudden onset of fever, nonproductive cough, dyspnea, tachypnea |intracystic bodies (opposed comma-like particles) |

|(1st disease diagnosed in >50% of AIDS pts. |(cysts in alveoli: inflammation( frothy exudate blocking gas exchange ( |(bilateral rales and ronchi |

|(most people have been exposed |no invasion of lung tissue |(TMP-SMZ or pentamidine |

|Trypanosoma cruzi (Chagas’ disease) |(chagoma (Romana sign) near bite site: facial edema (periorbital, perioral) + nodule |(blood smear( trypomastigotes |

|(South and Central America |(myocarditis/cardiomyopathy( arrhythmia( death |(xenodiagnosis: reduviid bug bites host( look for |

|(infected reduviid bug bites and defecates |(megasyndrome: megacolon, enlarged heart, enlarged esophagus |epimastigotes in gut |

|(trypomastigotes contained in feces enter host bloodstream( local |(meningoencephalitis in AIDS patients |(nifurtimox or benznidazole: kill trypomastigotes in|

|replication in M( and infiltration( chagoma | |blood; less effective against amastigotes in tissue |

|(nonflagellated, round amastigotes w/in host cells (myocardial, |(trypomastigotes multiple and differentiate into epimastigotes in insect gut( become |(no effective therapy for chronic disease |

|glial, reticuloendothelial) |trypomastigotes passed in insect feces | |

|Trypanosoma gambiense (Western Africa) |(metacyclic trypomastigotes ingested in blood meal by tsetse fly |(blood smear( trypomastigotes |

|(humans only (slower: kills in months-years) |(procyclic stage: multiplication in insect midgut( migrates to salivary glands( transforms |(aspirate of chancre or enlarged LN( parasites |

|Trypanosoma rhodesiense (Eastern Africa) |to epimastigotes( multiply more and forms metacyclic trypomastigotes carried by fly( bite |(suramin: curative if given before onset of |

|(zoonotic (more severe: kills in weeks-months) |host |encephalitis (does not cross BBB( no CNS penetration)|

|(African Sleeping Sickness |(enter bloodstream and become blood-form trypomastigotes |(melarsoprol: extremely toxic but used if CNS |

|(painful bite of Tsetse fly |(hard, red painful skin ulcer: heals within 2 weeks |involvement |

|(antigenic variation on surface glycoproteins |(lymphadenopathy and intermittent weekly fever; dizziness |(pentamidine: alternative drug |

|(VSG: > 100 genes, but 1 expressed at a time due to gene |(demyelinating encephalitis: daytime drowsiness, dysarthria, muscle tremors, apathy( coma | |

|rearrangement |and death (usu. from pneumonia) | |

| | | |

|Leischmaniasis: |(attachment to M( mediated by 2 molecules on parasite: |(presence of amastigotes in skin lesion or BM, |

|Leishmania donovani( visceral leishmaniasis |( 1) gp 63 (glycoprotein) 2) LPG (lipophosphoglycan) |spleen, LN biopsy |

| |and several molecules on M(( C3 receptor, LFA1, p150,95 | |

|Leishmania tropica (Old World)(cutaneous |(visceral leishmaniasis (Kala-azar): double peak (diurnal) fever, hepato-splenomegaly, |(skin test (using leischmanin: crude homogenate of |

|Leishmania mexicana (New World)(cutaneous |pancytopenia, immunosuppression, ( IgG |promastigotes) |

| |( affect organs of reticuloendothelial system (liver, spleen, BM) | |

|Leishmania braziliensis( mucocutaneous |( hyperpigmentation of light-skinned patients |(sodium stibogluconate |

| | | |

|(painless bite of sandfly |(cutaneous: initially, red papule at bite site( enlarge( satellite nodules that coalsce & | |

|(ingestion of amastigotes in M( of host |ulcerate( Oriental sore, Chiclero’s ulcer | |

|(amastigotes able to live at pH=4 (cytoplasm) |( ( in CMI( large areas of skin affected ((leprosy) | |

|(differentiate to promastigotes( migrate to pharynx of sandfly( | | |

|infect on next bite |(mucocutaneous: papule at bite site( metastatic lesions at mucocutaneous junction of | |

|(reside in phagolysosome of M( |nose-mouth( destroy nasal cartilage | |

|(reservoir: forest rodents |( death 2( to infection, starvation, aspiration pneumonia | |

HELMINTHS (WORMS):

|Cestodes: Tapeworms | | |

|Taenia solium (pork tapeworm) |(pig ingests egg-infested human feces( eggs develop into larvae that disseminate through |(gravid proglottids w/ 5-10 primary uterine branches |

|(ingestion of raw, cured, undercooked pork containing larvae |intestine into muscle of animal and develop into cysticercus( uncooked pork with larvae |in stools |

|(cysticerci) |eaten by humans( cysticercus attach to gut wall: anorexia, mild diarrhea |(T. saginata has 15-20 branches) |

|(cysticercus: pea-sized fluid-filled bladder |(larvae take (3 months to grow to adult size (5 m) |(calcified cysticerci on CT scan |

|(scolex has 4 suckers and circle of hooks |(ingestion of eggs( cysticercosis: eggs hatch into larvae in gut and penetrate into tissue |(larvae floating in vitreous |

|(attach to gut wall |and encyst( usually asymptomatic until larvae dies in 4-5 years( inflammatory response: |(niclosamide |

| |anaphylactic shock, retinitis/uveitis, seizures, meningitis, death |(praziquantel for cysticercosis |

|(worldwide, but endemic in Mexico, Latin America, Spain, Portugal, | |(( Ca++ permeability( paralyze worm; Ab-mediated WBC |

|Africa, SE Asia | |killing) |

|Taenia saginata (beef tapeworm) |(cattle ingest gravid proglottids detached daily and passed in human feces( embryos |(gravid proglottids w/ 15-20 primary uterine branches|

|(ingestion of raw or undercooked beef containing larvae |(oncospheres) emerge from egg and burrow into cow’s intestine( larvae in muscle of cattle |in stools |

|(cysticerci) |(larvae take (3 months to grow to adult size (10 m) | |

|(scolex had 4 suckers and NO hooklets |(most are asymptomatic: anorexia and mild diarrhea |(niclosamide for intestinal worms |

|(worldwide, but endemic in Africa, S. America, Europe |(do not cause cysticercosis in humans |(uncouples oxidative phosphorylation |

| | |(immobilization(expulsion) |

|Diphyllobothrum latum (fish tapeworm) |(larvae attach to gut wall and become adult worms( gravid proglottids release fertilized |(oval (other tapeworms are round) eggs w/ lidlike |

|(ingestion of undercooked fish containing larvae (plerocercoid or |eggs and passed in stool( fresh water |opening (operculum) |

|sparganum larvae) |(eggs eaten by crustacean(differentiate to larvae( eaten by fish |(longest tapeworm (up to 13 m) |

|(no suckers; 2 elongated suckling grooves |(most are asymptomatic: abdominal discomfort and diarrhea | |

|(Scandinavia, Japan, northern Russia, Canada |(absorb vitamin B12: megaloblastic anemia |(niclosamide |

|Echinococcus granulosus (dog tapeworm) |(1000’s of worms in dog’s intestines(eggs passed out in feces and contaminate environment |(brood capsules containing multiple protoscoleces |

|(ingestion of eggs by humans |and ingested by sheep (or humans) |(CT scan and tissue biopsy |

|(dog=definitive host (sheep=intermediate host |(oncosphere embryos emerge( migrate to liver (or lungs, bones, brain)( large fluid-filled |(surgical removal of cysts |

|(human=dead end intermediate hosts |hyatid cysts |(hypertonic saline( kill organism |

|(sheep-raising areas: CA, AZ, NM, Alaska, Canada, S. America, |(cyst rupture( anaphyaxis | |

|Africa, Mediterranean |(liver cyst( hepatic dysfunction (lung cyst( bloody sputum |(albendazole |

|(scolex w/ hooks, but only 3 proglottids (one of smallest tapeworm)|(brain cyst( headache, focal neurologic signs |(niclosamide |

|Hymenolepis nana (dwarf tapeworm: smallest) |(no intermediate hosts: humans ingest eggs( reinfect humans |(8-10 polar filaments between hooks |

|(most frequently found tapeworm in U.S. |(abdominal discomfort and nausea/vomiting |(praziquantel |

|Trematodes: Flukes | | |

|Schistosomiasis (blood flukes): |(in definitive venos site, female lays fertilized eggs( penetrate vascular endothelium( |(molecular mimicry: incorporating host antigens onto|

|S. mansoni (African, Middle East, S. America), S. japonicum |enter gut or bladder lumen( eggs excreted in stools or urine( hatch in fresh water( ciliated|surface( fool host’s immune system |

|(Orients, water buffalo, pigs) (affect GI system (live in |larvae penetrate snails(develop & multiple(many cercariae | |

|mesenteric veins) | |(S. mansoni: prominent lateral spine |

| |(most pathologic findings from presence of eggs in liver, spleen, or wall of the gut or |(S. japonicum: small lateral spine |

|S. haematobium (Africa, Middle East) affects urinary tract (adults|bladder |(S. haematobium: terminal spine |

|live in urinary bladder) |(acute phase: itching, dermatitis, fever/chills, diarrhea, lymphadenopathy, | |

| |hepatosplenomegaly, eosinophilia |(praziquantel: initial exacerbation of symptoms |

|(free-swimming, fork-tailed cercariae penetrate the skin ( | |(death evokes vigorous immune response) |

|“Swimmer’s Itch” |(S. mansoni, S. japonicum: GI hemorrhage, hepatosplenomegaly | |

| |(eggs in liver( granulomas( fibrosis, hepatomegaly, portal hypertension( splenomegaly), | |

|(adults exist as separate sexes but live attached to each other: |death from exsanguination from ruptured esophageal varices | |

|female resides in a groove in the male, “the schist”, where he | | |

|continously fertilizes her egg |(S. haematobium: hematuria; superimposed bacterial UTI’s; granulomas, fibrosis of bladder( | |

| |carcinoma of the bladder | |

|Clonorchi sinensis (Oriental liver fluke) |(excystation in duodenum(enter biliary ducts( bile duct fibrosis/ hyperplasia(bile duct |(typical small, brownish, operculated eggs in stool |

|(ingestion of undercooked fish w/ cercaria |carcinoma (cholangiocarcinoma) |(praziquantel |

|(snail is intermediate host (ingests eggs) |(upper abdominal pain, anorexia, hepatomegaly, eosinophilia | |

|Paragonimus westermani (lung fluke) |(enters the lung parenchyma( hermaphroditic adults produce eggs that enter bronchioles( |(typical operculated eggs in sputum or feces |

|(ingestion of raw crab meat w/ larvae |chronic cough w/ bloody sputum |(praziquantel |

|(penetrate GI wall( migrate thru diaphragm |(TB-like: pleuritic chest pain, dyspnea, recurrent bact. pneumonia | |

|Fasciola hepatica (sheep liver fluke) |(larva excyst in duodenum( penetrate gut wall( reach liver |(praziquantel |

|(sheep and other domestic animals in Latin America, Africa, Europe,|(RUQ pain, fever, hepatomegaly( obstructive jaundice | |

|and China |(halzoun: painful phayngitis from adult flukes on posterior wall( flukes acquired from |(surgically remove adult flukes in pharynx and larynx|

|(eating watercress (or other aquatic plants) contaminated by larvae|eating raw sheep liver | |

|Fasciolopsis buski (intestinal parasite of hymans and pigs) |(eating aquatic vegetation carrying cysts |(typical eggs found in feces |

|(endemic to Asia, India |(pathology due to damage of intestinal mucosa by adult fluke |(praziquantel |

| |(most asymptomatic; may have ulceration, abscesses, hemorrhage | |

|Heterophyes heterophyes |(inflammation of intestinal epithelium: abdominal pain, nonbloody diarrhea |(typical eggs found in feces |

|(eating raw fish (Africa, Asia) w/ cysts | |(praziquantel |

|Nematodes (Intestinal): Roundworms | | |

|Enterobius vermicularis (pinworm) |(lifecycle confined to humans: eggs hatch in small intestine, where larvae differentiate to|(”Scotch tape” of perianal skin |

|(ingestion or inhalation of worm eggs |adults and migrate to colon and mate |(eggs not found in stools |

|(most common helminth in U.S. (mostly affects children < 12) |(female migrates to anus at night and releases 1000’s of eggs |(mebendazole or pyrantel pamoate |

| | |(only kill adult worms, not eggs) |

| |(majority: asymptomatic, some( perianal pruritus |(may require retreatment |

|Trichuris trichiura (whipworm) |(eggs hatch in GI( migrate to cecum and ascending large intestine(mature adult produces |(typical eggs (barrel-shaped w/ plugs at each end) in|

|(ingestion of eggs in soil contaminated w/ feces |1000’s of eggs/day for 6-8 yrs |stool |

|(slow life cycle (incubate 3-6 wks in soil) |(abdominal pain and diarrhea |(mebendazole |

|Ascaris lumbricoides (largest intestinal: >25cm) |(larvae migrate through gut wall into bloodstream into the lungs |(transient pulmonary infiltrates and eosinophilia |

|(ingestion of eggs in soil contaminated w/ feces |(up bronchi and trachea and swallowed( become adults in SI |(Loeffler’s syndrome) |

|(very common (esp. in tropics, and southern states in the U.S.) |(live in lumen, does not attach to wall( 1000’s of eggs/ day |(oval eggs with irregular surface in stools; |

|(major damage occurs during migration rather than presence of adult| |occasionally, adult worms |

|worms in the intestine |(ascariasis: pneumonia w/ fever, cough, and eosinophilia | |

| |(adult worms can cause abdominal pain and obstruction |(mebendazole or pyrantel pamoate |

|Ancylostoma duodenale (Old World) |(larvae carried by blood to lungs(migrate into alveoli and up bronchi and trachea( |(transient pulmonary infiltrates and eosinophilia |

|Necator americanus (New World hookworm) |swallowed( become adults in SI |(Loeffler’s syndrome) |

|(filariform larva in moist soil penetrate skin |(attach to wall (cutting plates: Necator or teeth: Ancylostoma) |(eggs in stool |

|(worlwide distribution, esp. tropical areas |(eggs develop 1st into noninfectious, feeding (rhabditiform) larvae |(occult blood in stool frequent |

|(endemic in southern states |( then into 3rd stage, infectious, nonfeeding (filariform) larvae | |

|(major damage occurs during migration rather than presence of adult|(”Ground itch”: pruritic papule or vesicle at entry site |(mebendazole or pyrantel pamoate |

|worms in the intestine |(loss of blood( microcytic anemia (weakness and pallor) | |

|Strongyloides stercoralis (small roundworm) |(larvae molt into adults in small intestine( eggs hatch in mucosa |(larvae in stool |

|(2 distinct life cycles: |(rhabditiform larvae passed in feces( entire life cycle in soil |(striking eosinophilia (seen in all migratory |

|1) w/in human body 2) free-living in soil |(or filarial larvae, which penetrates intestinal wall directly w/o leaving host and migrate |nematode infections) |

|(penetration of skin by infectious (filariform) larvae(migration up|to lungs (autoinfection) | |

|trachea and swallowed |(pneuminitis w/ coughing and wheezing |(thiabendazole or mebendazole |

|(major damage occurs during migration rather than presence of adult|(if high worm burden( female worms: inflammation of mucosa | |

|worms in the intestine |(hyperinfection ((( damage) in immunocompromised: bloody, watery diarrhea and sepsis from | |

| |infiltration of enteric bacteria | |

|Trichinella spiralis |(gastroenteritis a few days after eating undercooked pork |(larvae w/in striated muscle |

|(eating undercooked pork (U.S.: home-made sausages) w/ larvae |(1-2 weeks later: fever, muscle pain, periorbital edema, eosinophilia (CNS, cardiac |(steroids plus mebendazole |

|encysted in striated muscle |symptoms frequent |(not very effective) |

|Nematodes (Tissue): Roundworms | | |

|Wuchereria bancrofti (Pacific Islands, Africa) |(After 1 year: mature to adults that produce microfilaria (L1)( circulate in blood (mainly |(thick blood smears from patient at night reveal |

|Brugia malayi (Malay Peninsula, SE Asia) |at night)( ingested by mosquito( microfilaria produce infective larva (L3) transferred w/ |microfilariae |

|(female mosquito (Anopheles, Culex) bites and deposits infective |next bite | |

|larva (L3) that penetrates skin and enters lymph node |(early: asymptomatic (late: fever, lymphangitis, cellulitis |(diethylcarbamazine (against microfilaria only( |

| |(obstruction of lymphatics( edema of legs and genitalia (elephantiasis) |paralyze) |

|Onchocerca volvulus |(differentiate into adults, usually within dermal nodules |(ivermectin (microfilaria only( ( GABA(muscle |

|(female blackfly Simulium deposits infective larvae while biting( |(”river blindness” (infection rate > 80% in endemic areas) |paralysis) |

|subcutaneous tissue |(disease: cellular immune response to death of microfilariae |(suramin (kills adults, but toxic) |

|Loa loa |(females release microfilariae that enter blood (daytime)(taken up by fly during |(visualization of microfilariae in a blood smear |

|(bite of deer fly Chrysops deposits infective larva on skin( wander|bloodmeal(differentiate to infective larvae…. | |

|in body( become adults | |(diethylcarbamazine (microfilariae only) |

| |(Calabar swellings: hypersensitivity rxn causing transient (2-3 days), localized, |(surgical excision of worms in eyes |

| |erythematous, subcutaneous edema | |

| |(adult worm crawling across the conjuctiva (harmless) | |

|Dracunculus |(larvae released in small intestine and migrate to body( adults |(head of worm in the skin ulcer: worm looped out |

|(tiny crustaceans w/ infective larvae swallowed in drinking water |(adult females cause skin to ulcerate and release motile larvae |under the skin and slowly pulled out over course of |

| |(burning, itching inflamed papule w/ ulceration |days |

|Nematode Larvae Diseases: | | |

|Toxocara canis |(adult female in dog intestine produces eggs that are passed in feces into the soil( human |(eosinophilia (larval migration) |

|(major cause of visceral larva migrans |ingest soil w/ eggs( larvae in SI |(hypergammaglobulinemia |

|(definitive host is dog; humans: dead-end hosts |(migration to many organs (liver, brain, and eyes) | |

|(young children (more likely to ingest soil) |(granulomas form around dead larva (delayed hypersensitivy) |(diethylcarbamazine |

| |(blindness due to retinal involvement; fever, hepatomegaly | |

|Ancylostoma caninum (dog hookworm) |(larvae penetrate skin and migrate through subcutaneous tissue causing an inflammatory |(oral or topical thiabendazole |

|Ancylostoma braziliense (cat hookworm) |response( prurutic lesions (“creeping eruption”)( similar eruptions w/ Strongyloides and | |

|(children, construction workers exposed to infected soil (mainly |Necator | |

|southern U.S.) | | |

|Anisakis |(can penetrate submucosa of stomach or intestine |(no effective drugs |

|(ingested in raw seafood (sushi, sashimi) |(gastroenteritis, eosinophilia, and occult blood in stool | |

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