I&i Week 8 [All Parasites]

Front 1

Toxoplasma gondii

Back 1

GENERAL: apicocomplexan, transmission by ingestion of sporulated oocyst from cat (def host) feces or cyst containing meat/vertical transmission LIFE CYCLE: Sexual cycle completed in cat, oocyst passed in feces which sporulates in environment and is then infective; obligate intracelluar parasite of most nucleated cells; DISEASE: Toxoplasmosis: invastion of nucleated cells (ex: liver), ingestion by macrophages, local and hematogenous spread, trophozoites (block phagosome-lysosome fusion) become bradyzoites, bradyzoites wall off to become pseudocyst, becomes latent infection. Congenital/ Neonatal infection: chorioretinitis, microcephaly, diffuse intracranial calcifications, neurological abnormalities, deafness, ocular infection ACUTE INFX: mono-like illness, fever, lymphadenopathy, hepatosplenomegaly; IMMUNOCOM'D HOST: myocarditis Reactivation: AIDS PTS: seizures, headache, focal findings, chorioretinitis (more common in Non-AIDS pts), meningoencephalitis; DX: serology/FA stain biopsy

Front 2

Cryptosporidium spp.

Back 2

GENERAL: apicocomplexan, Imunnocomp'd (AIDS pts were really common), cattle for parvum, Ingestion of oocyst (fecal-oral, contaminated water/ food); LIFE CYCLE: Oocyst reps intracellularly but extracytoplasmic location/superficial patchy small intestine infx-->Diarrhea which can persist in immunocompromised hosts, localized in small intestine/ gall bladder (rare); DISEASE: Cryptosporidiosis (2-14d incub) watery, persist for months - lifetime, usually lasts 2-7d; DX: Stool for modified acid fast stain or FA of stool MORE SENSITIVE /can look like Candida use acid fast

Front 3

Giardia lamblia

Back 3

GENERAL: flagellate, fx IgA def; LIFE CYCLE: Ingestion of cyst (fecal-oral, contaminated water), beaver other reservoirs-->Asymptomatic (most people) to protracted diarrhea; DISEASE: Giardiasis: diarrhea, foul-smelling stools, abdominal cramps, bloating, weight loss, some have malabsorption; DX: Stool for cysts or trophsx3, stool IFA or ELISA, duodenal aspirate (helpful for other diff dx), string test

Front 4

Entamoeba histolytica

Back 4

GENERAL: lower SES, tropica regions; fecal-oral/contaminated H20/sexual LIFE CYCLE: Primary invasion of colon (excyst as trphozoite); invasion through mucosa causes necrosis; kill neutrophils, ingest RBCs; secondary abscess in liver or rarely other organs, encyst to pass in feces; DISEASE: amebiasis/ amebic dysentery: abdominal pain, bloody diarrhea, liver abcesses, RUQ pain, fever, elevated liver enzymes, flask-shaped ulcers in colon; DX: Stool for trophozoites or cysts x3; Trophozoites with ingested RBC are pathognomic; serology (PREFERRED test overall) also for invasive disease, indirect hemagglutination, no fecal leukocytes

Front 5

Naegleria fowleri

Back 5

GENERAL: Ameba; fresh water reservoir LIFE CYCLE: Travel up olfactory nerve to invade via nasal mucosa brain, cause acute meningitis; DX: Visualize organisms in CSF; they look similar to monocytes

Front 6

Trichomonas vaginalis

Back 6

GENERAL: flagellate LIFE CYCLE: DOES NOT HAVE A CYST STAGE; Infects vaginal epithelial cells and causes vaginitis DISEASE: Trichomoniasis: usually femals, foamy dischage/dysuria; males usually asymptomatic; DX: Visualize motile organisms from vaginal specimen

Front 7

Plasmodium falciparum, vivax, ovale, and malariae

Back 7

GENERAL: Apicocomplexan, fx People with Duffy receptor, and people with Ss trait, alpha thalassemia, hemoglobin C; LIFE CYCLE: Hepatic Phase: ANOPHELINE mosquito (vector) bites and injects sporozites which travel to liver. (1-2w) rupture and release merozoites. RBC Phase: invasion (1-2d), rupture simultaneously Sequesteration ONLY S. falciparum; infected cell develops male and female and infects mosquito. P. vivax invades reticulocytes; DISEASE: Malaria: periodic high ever (40-41C), chills, musculoskeletal pains, severe headache, diarrhea; “P. falciparum capillary occlusions especially dangerous. Cerebral Malaria: children with seizures and coma. Severe anemia: Hgb < 5, RBC lysis, removal by spleen, dyserythropoiesis; DX: Blood smear, thick & thin, obtained several times in 24 hr, FALCIPARUM HAS HIGH LEVEL OF PARASITEMIA (20-30% >1-2 vivax), SHORTER LATENT PERIOD (10-13 days < 12-24 vivax)
TX: Falciparum: Artemisin+, Quinine+, Chloroquine+ (only Cen. America/Middle East); Others: Chloroquine (some vivax susceptible), Primaquine; PREVENT: netting, repellent, chemotherapy (Chloroquine/Mefloquine/Doxy/Malarone), selective DDT use

Front 8

Leishmania spp.

Back 8

GENERAL: Kinetoplast; LIFE CYCLE: sandfly vector bite, l. donovani, tropica, are human other multiple reservoirs 1. sand fly takes up amastigotes 2. infects animal, 3. transforms to promastigotes in stomach 4. invages mid-gut 5. taken up by monocyte 6. fusion of lysosome causes change to amastigotes 7. burst monocyte DISEASE: Visceral leishmaniasis: caused by L. donovani. Seen in spleen and liver with hypergammaglobulinemia, hypersplenism and death. Mucocutaneous Leishmaniasis: caused by L. braziliensis, primary nodule, destruction of nasal and mucosal tissue. Cutaneous leishmaniasis: caused by L. mexicana, ulcerative lesions; DX: Microscopic visualization or culture of organism from lesion

Front 9

Trypanosoma brucei gambiense

Back 9

GENERAL: Kinetoplast; LIFE CYCLE: Tsetse fly vector; chancre at site of painful bite, has hundreds of VSG surface proteins that are selectively used due to immune response1. Hemolymphatic phase: relapsing fever and lymphadenopathy; 2. Meningoencephalitis: CNS infection (sleeping sickness); DISEASE: West African trypanosomiasis: (m-y) for stage 2, daytime somnolence and nighttime insomnia, progression to coma; DX: Blood or CSF smear, biopsy specimen

Front 10

Trypanosoma brucei rhodesiense

Back 10

GENERAL: Kinetoplast; LIFE CYCLE: Tsetse fly vector; chancre at site of painful bite, has hundreds of VSG surface proteins that are selectively used due to immune response 1. Hemolymphatic phase: relapsing fever and lymphadenopathy; 2. Meningoencephalitis: CNS infection (sleeping sickness); DISEASE: East African trypanosomiasis: (w-m) for stage 2, daytime somnolence and nighttime insomnia, progression to coma, more acute; DX: Blood or CSF smear, biopsy specimen

Front 11

Trypanosoma cruzi

Back 11

GENERAL: Kinetoplast, Central & South America; LIFE CYCLE: Reduviid bug vector; bite-->puritic wound Trypomastigotes travel to cells become amastigotes, feces of vector introduced when scratched. Initial infection may cause systemic, cardiac or CNS disease, followed by indeterminate infection, then mega-disease DISEASE: Chagas disease; American trypanosomiasis: nerve destruction, muscle inflammation/hypertrophy, Romona's sign:painless periocular swelling when parasite enters via mucosal surfaces. Acute Chagas: chagoma (ulcer), local inflammation, parasitemia, lymphocytosis, lymphadenopathy, fever/sometimes meningoenceph/myocarditis/Romana's. Inderterminant phase: mild parasitemia. Chronic Phase: cardiac arrheythmias, cardiomyopathy, CHF. GI: dysphagia, odynophagia, regurgitation, constipation, ab pain, perforation; DX: Serology, blood smear

Front 12

Enterobius vermicularis (pinworm)

Back 12

GENERAL: Nematode; LIFE CYCLE: fecal-oral; Adults in rectum and colon; (pinworm) Most common parasite of children; anal pruritis; restlessness; DISEASE: Emperor of pruritis ani: (4w) females migrate out of the anus at night and expel eggs. Eggs hatch in small intestine, larvae hatch in colon; DX: Cellulose tape for ova; Collect first thing in morning

Front 13

Trichuris trichiura (whipworm)

Back 13

GENERAL: Nematode; LIFE CYCLE: Adults in colon and rectum; burrow into epithelium with posterior protruding into lumen [esp dirty dirt-eating children]. DISEASE: (90d) light infections asymptomatic; heavy infections may cause diarrhea, tenesmus and RECTAL PROLAPSE; anemia, malnourishment; DX: stool for ova BARREL shaped

Front 14

Ascaris lumbricoides (roundworm)

Back 14

GENERAL: Nematode; LIFE CYCLE: requires development in the soil before infective (fecal-oral); larvae burrow in small intestine, hematogenous spread to liver, heart and lungs, larvae coughed up and swallowed, mature to adults in small intestine [especially in children]; DISEASE: light infections asymptomatic; occasional intestinal obstruction or migrations of adult in heavy infection. Migratory phase: release antigen in alveolar capillaries causing eosinophilia, elevated IgG and ASTHMA CONDITION. Intestinal phase: adults entangle and block lumen, may perforate or block bile duct; DX: Stool for ova

Front 15

Necator americanus or Ancylostoma duodenale (hookworm)

Back 15

GENERAL: Nematode;LIFE CYCLE:Adults in small intestines;(hookworm) duodenale penetrate skin, eggs pass out of feces and hatch in stool [especially in children], develop in soil-->skin contact (feet) initiates; [ancylostoma can be ingested] DISEASE: Migratory phase: itching, dermatitis with larvae is skin [think less severe Ascaris]. Intestinal phase: light Infections asymptomatic; heavy infection plus malnutrition cause anemia-->impaired growth/mental retardation. DX: Stool for ova

Front 16

Strongyloides stercoralis

Back 16

GENERAL: Nematode;LIFE CYCLE: free living and parasitic generation. Filariform penetrate skin and burrow into villi and lay eggs. Eggs are passed out of feces or migrate to liver, lung and trachea (AUTO INFECTION). DISEASE:Strongyloidiasis: Adults in small intestinal mucosa symptoms vary, i.e. asymptomatic mucoid diarrhea with malabsorption of fats (steatorrhea), potentially fatal in immunologically compromised host due to autoinfection; DX: Stool or duodenal aspirates for LARVAE; Baerman concentration (hydrophilic), Eosinophilia (>50%)

Front 17

Cutaneous larval migrans

Back 17

GENERAL: Nematode;LIFE CYCLE: Dog or cat hookworm penetrates thru intact skin and migrates thru skin : long tortuous red tracks, lasts 10d; DX: Clinical

Front 18

Toxocara canis

Back 18

GENERAL: Nematode; LIFE CYCLE: dog def host; Ingested ova hatch into larvae, which invade various organs hematogenously; eosinophilia; IgE; hepatosplenomegaly occasionally retinal granuloma due to larval migration DISEASE: Viscera larval migrans: depends on location where larvae encyst. Liver: fever, hepatomegaly. Retina: blindness. Eosinophilia granuloma similar to retinoblastoma; DX: Serology highly sensitive/specific; clinical judgment for eosinophilia, enlarged liver, dirt eating

Front 19

Trichinella spiralis

Back 19

GENERAL: Nematode;LIFE CYCLE: pig/rats/bears definitive host; ingesting viable larvae in meat (pork)-->small intestine/blood-->encyst in muscle by penetrating intestinal wall (use lymphatics to reach cells). Become adults in 30h. Intestinal phase 2-3w and expelled; DISEASE: Trichinosis: (intestinal phase)--nonsepecific GI disturbances depending on #larvae ingested; (parental phase)--larvae cause muscle pains,ocular edema, eosinophilia, splinter hemorrhages under nails, fever, vasculitis, CNS involvement, death ); DX: clinical evidence (myositis, eosinophilia, circumorbital edema), hx of pork eating; serologic tests; muscle biopsy

Front 20

Wuchereria bancrofti

Back 20

GENERAL: Nematode; LIFE CYCLE:: Bite of infected mosquito (vector)-->Larva develop into adults in hosts; immune response to these causes scarring which may develop to elephantiasis DISEASE: Acute Filariasis: fever, chills, headache, leukocytosis, marked eosinophilia, local swelling; elephantiasis/ obstructive filariasis: poor lymphatic drainage, especially of legs and genitalia. Asymptomatic: good Ab and CMI. Tropical Pulmonary Eosinophilia: pulmonary infiltrates; DX: blood for microfilaria; may be day or night depending on local pattern, high IgE

Front 21

Brugia malayi

Back 21

GENERAL: Nematode; LIFE CYCLE: Bite of infected mosquito (vector)--> Inflammatory response and scarring in lymphatics, much directed against Wolbachia, the obligate endosymbiont; multiple mammal reservoirs; DISEASE: Acute Filariasis: fever, chills, headache, leukocytosis, marked eosinophilia, local swelling; Elephantiasis/ Obstructive Filariasis: poor lymphatic drainage, especially of legs and genitalia. Asymptomatic: good Ab and CMI; DX: blood for microfilaria; may be day or night depending on local pattern, high IgE

Front 22

Loa loa (African Eye Worm)

Back 22

GENERAL: Nematode; LIFE CYCLE: Tavanid/day biting redflies (vector) bite humans-->moves subQ then to subconjuntival space; monkeys additional reservoir; PATHO/DISEASE: Kalabar swellings (subQ), painful eye; DX: daytime blood for microfilaria

Front 23

Onchocerca volvulus

Back 23

GENERAL: Nematode; LIFE CYCLE: Bite of Simulium fly (vector) transfers-->larvae develop into adult worms in subcutaneous tissue cause formation of tumor-like nodules/symbiotic with Wolbachia (rickettsia)-->eye issues; DISEASE:onchocerciasis; river blindness: Microfilarial forms migrate through eye and may cause blindness; DX: Skin snip for microfilaria

Front 24

Clonorchis sinensis (Chinese Liver Fluke)

Back 24

GENERAL: trematode; LIFE CYCLE: human(def host) ingestion of uncooked fish-->hatches in intestine-->bile duct-->feces-->water to snails (int host)--> cercaria released onto fish (int host) DISEASE: majority ASYMPTOMATIC, Adults live in intrahepatic biliary tree and may cause gb or liver disease; DX: stool for ova

Front 25

Schistosoma mansoni, japonicum, or mekongi (Blood fluke)

Back 25

GENERAL: trematode LIFE CYCLE: Cercariae penetrate skin after leaving snail (int host)-->through lungs to liver and adults mate-->mesenterics venules, eggs escape in feces--> lateral spine eggs hatch invade snail. Swimmer's itch (2h) self limiting 2-3d; Swimmer's Fever/ Katayama (for acute disease): 3w after, splenomegaly, fever, diarrhea, constipation; eosinophliia Symmer's Fibrosis/ Bilharzia for chronic: portal HTN, esophageal varasies, ascides, hepatosplenomegaly, rectal varicose veins; DX: Stool & rectal biopsy for ova; Eggs may be scarce

Front 26

Schistosoma haematobium

Back 26

GENERAL: trematode LIFE CYCLE: Cercariae penetrate skin after leaving snail (int host)-->through lungs to liver and adults mate-->bladder venous plexus, eggs escape in urine-->terminal spine eggs hatch invade snail. PATHO/DISEASE: Granulomatous reactions in bladder; hematuria, hydronephrosis with renal failure, calcification and edema around ureter-bladder junction, increase bladder cancer; DX: Urine for ova; biopsy of bladder; Eggs may be scarce

Front 27

Paragonimus westermani

Back 27

GENERAL: trematode; EPI: Korea/Japan/Africa/Mexico; freshwater sushi LIFE CYCLE: humans (def host) ingestion of metacercaraie with raw or undercooked crab meat (int host)-->worms hatch thru small intestine-->peritoneum-->diagphragm-->lungs-->eggs pass from sputum and feces-->penetrate snail, crab; PATHO/DISEASE: Lung lesions from migration thru lungs/brown sputum (eggs are brown); DX: Ova in stool and sputu; TX: praziquantel

Front 28

Taenia saginata

Back 28

GENERAL: Cestodes: LIFE CYCLE: Humans (def host) Ingest larvae in beef (int host); humans release eggs from proglottids taken up by cows and larvae incorporate in them PATHO/DISEASE: eggs disseminated by proglottids break up; Vague GI disturbances, usually asymptomatic; DX: stool for proglottids or ova

Front 29

Taenia solium

Back 29

GENERAL: Cestode; EPI: undercooked pork, pigs eat garbage/human feces, pork meat proocessing TRANS:humans ingest pig (int host) with embryonated eggs OR ingest eggs directly (become int host like pig) PATHO/DISEASE: no symp w/ adult worm Cysticercosis: Larvae migrate to brain, eye, muscle--> epilepsy, death, seizures, hydrocephalus, focal neurological abnormalities, tumor-like; DX: Radiologic evidence of cysticerci in affected organ (CALCIFICATION); serology; TX: praziquantel or albendazole w/ corticosteroids

Front 30

Diphyllobothrium latum

Back 30

GENERAL: Cestode: TRANSMISSION: ingest contaminated fish; LIFE CYCLE: man (def host)-->fresh water-->crustacean-->fish; man infected while eating fish with larvae in muscle-->live in intestine (15m)-->proglottid released from from colon broken up into feces-->into water DISEASE: percicious megaloblastic anemia; VIT B12 def common; DX; eggs in stool specimen

Front 31

Echinococcus granulosus

Back 31

GENERAL: Cestode; EPI: pastoral societies with dogs, sheep, humans; TRANSMISSION: ingestion of dog feces LIFE CYCLE: dogs (definitive host) who pass tapeworm proglottids/ and eggs out of feces-->sheep eat contaminated forage; man ingests eggs (intermed hosts); PATHOGENESIS: Eggs mature to larvae which migrate to multiple organs (liver mostly lung/brain), causing cysts DISEASE: Hydatid disease: rapid growth of cysts causing pressure atrophy of adjacent organs.rupture can lead to anaphylactic shock; DX: skin/serolgical tests; TX: albendazole/surgery