Term
| Intracellular localization of parasites |
|
Definition
| microorganism use highly developed processes to gain access to and survive within hosts' cells (cytoplasm or vesicular compartments). ex: Malaria and RBC, Toxoplasma gondii and macrophages. |
|
|
Term
| Extracellular localization of parasites |
|
Definition
| Microbes residing at epithelial surface. ex. Giardia, large parasite (worms) in blood, lymph, tissue. |
|
|
Term
| What is colonization by microorganisms? |
|
Definition
| Penetrate host's epithelial barriers and are present but are not causing any disease. |
|
|
Term
| What do elevated eosinophils in blood indicate? |
|
Definition
| Parasitic helminths have surface glycoproteins and polysaccharides that stimulate eosinophils and IgE to increase in blood. |
|
|
Term
| What is a subclinical infection? |
|
Definition
| It is common. The parasite is in the host but host has no signs or symptoms. ex. toxoplasmosis |
|
|
Term
| What is an active symptomatic disease? |
|
Definition
| A parasitic infection that causes symptoms. Ex. malaria causes fever/chills. Subclinical infections may progress to symptomatic disease. |
|
|
Term
| What are intracellular parasitic protozoans? |
|
Definition
| Can't withstand drying in external environment. Their lifecycles don't include free environmental stages. Commonly transmitted from host to host by arthropod vectors. |
|
|
Term
| What are extracellular protozoans? |
|
Definition
Alternate b/w 2 forms: 1. Active trophozoite form that grows and replicates by binary fission. Motile parasitic stage. 2. Dormant cyst that transmitted b/w humans. relatively impermeable b/c double membrane, thus resist drying.
Transmitted by fecal-oral rout. |
|
|
Term
|
Definition
| multicellular/ extracellular parasites. Transmitted by oral ingestion (ascaris), Direct penetration of unbroken skin (hookworm), Arthropod vectors bites (filariasis). Cuticle for protection. Complex life-cycles with environmental and animal reserviors |
|
|
Term
|
Definition
| A form that grows and replicates by binary fission; motile parasitic stage. |
|
|
Term
|
Definition
| It is the parasitic stage that is transmitted b/w humans. Relatively impermeable b/c of double membrane, thus resist drying in external environment. |
|
|
Term
| What is the "parasitic burden"? |
|
Definition
| It is directly related to the numbers of parasites the host acquires from the environment. |
|
|
Term
|
Definition
| Living transmitters of disease. |
|
|
Term
| What is the general parasitic life-cycle? |
|
Definition
Human stages: 1.Infective stage 2. Maturation stage 3. replication
Extra Human stages: 4 Growth and development |
|
|
Term
| What are the key aspects of life-cycles of common parasites may help the physician deal with parasitic problems. |
|
Definition
1. b/f maturation: vaccine administered
2. b/f replication: chemoprophylaxis adm.
3. b/f infective stage: Control measures (potable water, pesticides) |
|
|
Term
| Environmental considerations with parasites. |
|
Definition
1. Climate: temp/rainfall affect vectors.
2. A component of the parasitic life-cycle may not be geographically located.
3. Sanitation issues: potable water
4. Control prevention strategies: environmental manipulation, ex: eradicate # mosquitoes, decrease malaria. Improve drinking water and sanitation. |
|
|
Term
| What are giardia's clinical presentations? |
|
Definition
1. Acute diarrhea:watery, foul-smell, abdominal discomfort, mild-severe dehydrated. Incubation 7-10 d.
2.Chronic diarrhea w/+/- malabsorption. Sxs may increase/decrease.
3.Asymptomatic infection
4.Lactase deficiency w/ or after infection. |
|
|
Term
| What are Trichomoniasis clinical presentations? |
|
Definition
1.Women: copious yellow/green vaginal discharge, vulvovaginitis, +/- vaginal bad odor, elevated pH (>4.5). Some have no or min. sxs.
2.Men: Usually asymptomatic. |
|
|
Term
| What are Cryptosporidiosis clinical presentations? |
|
Definition
1. normal host: self-limiting diarrhea for 1-2 wks. No Rx
2. Immunocompromised host (AIDS): chronic, intractable debilitating diarrhea. Hard to Rx.
3. Community outbreaks possible |
|
|
Term
|
Definition
Highly contagious, need >10 cysts. Spread by: 1. person to person (day care, sex)
2. Contaminated water 3. Foodborne, fecal contamination. Can get from wilderness (beaver fever). "traveler's diarrhea" |
|
|
Term
|
Definition
1.No fecal leukocytes
2. Stool for ova and parasite exam: 3 fresh samples of 2-3 d. Trichrome stain, sometimes - although infection is there. 95% positive.
3.Duodenal aspirate/biosy/string test
4.Giardia Stool antigen: Poly/monoclonal anitbody against cyst/trophozoite antigens used with ELISA test or immunoflourescent anitibody test. Highly specific/sensitive |
|
|
Term
| Drug of choice for giardia treatment in non-pregnant adults. |
|
Definition
| Metronidazole oral 3x/d 5d. |
|
|
Term
| How do you prevent a giardia infection? |
|
Definition
1. Proper handling/treatment water: chlorination, flocculation, sedimentation, filtration
2. Good personal hygeine: hand washing, avoid oral-anal contact.
3. Camping/hiking esp. in developing countries: boil water, sm. vol. water filter, treat water with chlorine, iodine. |
|
|
Term
| How do you prevent cryptosporidium infections? |
|
Definition
1. Avoid drinking water directly from lakes/rivers. Don't assume bottled water is safe. Community outbreaks, boil water for 1 min.
2. HIV patients: avoid contact with human/animal feces. If change diapers/litter wear gloves. Avoid farm animal feces. Use disposable gloves for gardening.
3. Good hand-washing, properly dispose contaminated materials.
4. Avoid fecal contamination in pools. |
|
|
Term
| What is the Dx for trichomonas in women? |
|
Definition
1. "wet mount" of vaginal secretion. Examine in ER w/ microscope.Look for motile trophs. 60-70% sensitivity.
2. Culture: results 3-7 d.
3.PCR: none FDA approved yet
4. Pap smear sometimes |
|
|
Term
| What are the Rx for trichomoniasis patients and sexual partners? |
|
Definition
1. DOC: 2g metranidazole orally single, or 500mg for 7d.
2. Pregnant women, single dose regime.
3. note: resistance to metronidazole can occur. |
|
|
Term
| What is the Dx for cryptosporidium? |
|
Definition
Examine stool specimen:
1. EIA enzyme immunoassay, detects cryptosporidial antigens
2.Modified acid-fast stains on + EIA test: oocytes stain bright red against green fecal debris
3. Immunofluorescent stains: use monoclonal antibody directed at cyst wall.
4. Fecal WBC: - |
|
|
Term
| What are the Rx for cryptosporidium? |
|
Definition
1.normal host: no therapy
2. immunocompromised (AIDS):difficult: no DOC; effective HIV antiviral Rx help decrease developing severe case. replace fluids if sxs severe. |
|
|
Term
| What are the clinical presentation of amebiasis? |
|
Definition
1. Asymptomatic intestinal "infection" (85-95%). Stools have cysts, no tissue invasion. - serum antibody, normal colonoscopy.
2. Amebis colitis/dysentery: Onset several d. mucoid diarrhea, gross or occult blood. Abdominal discomfort +/- fever. Trophs cause this.
3. Liver abscess:fever, RUQ abd. pain, tender over liver. Majority w/o diarrhea. |
|
|
Term
| In what patient settings might amebiasis develop? |
|
Definition
1. Most common in developing countries, 1most likely to occur in immigrants and travelers to endemic regions.
transmission through fecal exposure.
2. In US: institutionalized populations of mentally challenged, homosex. males, recent immigrants, migrant workerd from endemic areas. |
|
|
Term
| What is the Dx of intestinal amebiasis? |
|
Definition
| 1. Stool exam for cysts may be -, even w/ disease, therefore, take multi specimens. Problematic: two different amoebae look same under microscope a. E. histolytica: cause disease b. E.dispar: no disease |
|
|
Term
| What is the Dx of extra-intestinal amebiasis? |
|
Definition
1. W/ liver abscess: 10% have cysts in stool.
2. Aspirate liver abscess: 20% trophs
3. CT scan: dx abscess, but could be tumor, bacterial
4. high index of suspicion: young male immigrants from developing countries, or prior travels to those areas. |
|
|
Term
| How do you prevent amebiasis? |
|
Definition
1. Improve waste disposal, water purification: boil water
2.In tropical developing countries assume water and fruits/veg are contaminated
3.Avoid fecal-oral contact. |
|
|
Term
| What is the rare clinical problem that Naegleri fowleri may cause? |
|
Definition
| It is a primary amebic meningoencephalitis in normal childres/young adults. Hx swimming in warm water ponds in past wk. can gain access to CNS through nasal mucosa and cribriform plate. Usually fatal. |
|
|
Term
| What is the major global importance of malaria? |
|
Definition
| Est. 2.5 billion live in infected areas. 300-500 million infected. Kills 1-3 million/year (mostly kids <4 y/o). Sub-saharn Africa 25-50% of all hospitalization. US, 1200-1400 cases/yr (returning travelers), a lot not dx correctly in US. Huge economic effect |
|
|
Term
| How is an American physician involved in "rare" malaria dx? |
|
Definition
1. If patient has a fever and came from travelling in endemic area, possible dx.
2. Use chemoprophylaxis for those going to high risk areas. |
|
|
Term
| What are the clinical presentation of malaria? |
|
Definition
1. Potentially life-threatening:ssx:
non-specific fever, non-specific anemia, non-specific splenomegaly, CNS problems w/ P.falciparum, Nephrotic syndrome w/ P. malariae, malaise. |
|
|
Term
| Why would a case of P. falciparum be considered a medical emergency? |
|
Definition
| If high % RBC parasitized then: 1.Cerebral malaria--> stupor to coma, death w/in 24 h. 2. Other complications: Seizures, Acute renal failure, ARDS, Disseminated intravascular coagulation with hemoglobiurnia, severe anemia, hypoglycemia, hypotensive shock. 3. Increased fetal/maternal mortality in pregnant women. |
|
|
Term
| What is the malaria life-cycle? |
|
Definition
1. Infected female Anopheles mosquito bites human, injects malarial sporozoites from her saliva.
2. Exo-erythrocytic phase: Sporozoites enter liver cells.
3. Some P. vivax or ovale (not falciparum or malariae) can remain dormant hypnozoites for months-5y.
4. Merozoites released
5. (transfer by transfusion/ share infected needles. therefore no hepatic cycle.)
6. Erythrocytic Cycle: Penetrate RBC to make ring trophozoites.
7. Mature into schizonts.
8. RBC's release merozoites: causes sxs, continue cycle.
9. Gametocytes taken up during blood meal by female Anopheles mosquito.
10. Parasite multiplies w/in GI tract of mosquito, in sporozoite form migrates to salivary gland. |
|
|
Term
| What is the Dx for malarial blood smears? |
|
Definition
1. "Thick smears": see if parasite present, harder to interpret.
2. "Thin smears": speculate the species involved and % RBC infected if P. falciparium involved. Easier to interpret.
Smears stained w/ either Wright-Giemsa or Giesma stain. |
|
|
Term
| What is the Rx for acute malaria? |
|
Definition
| Oral quinine sulfate 7d., oral coxycycline 7d, then oral primaquine 14d (prevent relapses from hepatic form of P. vivax) |
|
|
Term
| How do you prevent malaria? |
|
Definition
1. reducing vector-human contact:
decrease mosquito population, insecticide-impregnated bed net, insect repellant (DEET), wear long sleeves, pants at dawn, dusk, evening.
2. Chemoprophylaxis: medication to prevent malaria to traveler:
chloroquine susceptible malaria: take oral chloroquinine weekly.
for cholorquinine resistant malaria: Atovaqone/proquanil, doxycycline, Mefloquine (Larium). |
|
|
Term
| What is the pathophysiology of P. falciparum malaria? |
|
Definition
| P. falciparum only human malaria parasite: microvascular disease. As it matures, knobs appear on surface of parasitized RBC, that helps cytoadherence to endothelial cells in capillaries and post-capillary venueles of brain, kidner, affected organs. Causes hypoglycemia (parasite glucose consumption), lactic acidosis (glucose depletion, acidosis at tissue level, decrease BP) |
|
|
Term
| What hemoglobulinopathies protect the host against malaria? |
|
Definition
1.Sickle cell and thallassemia decrease P. faliciparum mortality.
2.G6PD defiencency alters RBC, makes it inhospitable for bug.
3. P vivax binds to Duffy blood group antigens. Duffy antigen genetically determined and largely absent in blacks of Sub-saharan African ancestry, thus P. vivax rare in some regions of Africa b/c ppl not susceptible. |
|
|
Term
| What are the clinical implications of toxoplasmosis? |
|
Definition
Pathogen: Toxoplasma gondii
1. Most asymptomatic: subclinical infection.
2. Normal host can have transient mono-like syndrom w/ lymphoadenopathy.
3. Congenital disease: transplacental: early spontaneous abortion, neonatal infection (mental retardation, seizures, microencephaly)
4. Immunosupressed (AIDS): encephalitis
5. Chorioretinitis: eye problem |
|
|
Term
| How do humans acquire toxoplasmosis (what is its life-cycle)? |
|
Definition
1. cat definitive host for sexual stage of T. gondii.
2. Parasite multiply in cat, oocytes excreted. Oocytes last for months, resistant to disinfectants, drying, freezing.
3. Other animals intermediate hosts.
4. Humans get it 3 ways:
a. Ingest undercooked infected meat w/ toxo cycts.
b. Ingest oocyte from fecal contaminated food
c. transplacental infection to fetus.
3. |
|
|
Term
| How do you Dx toxoplasmosis? |
|
Definition
1. Serologic Dx: IgG + antibody: old/prior infection; elevated IGM key test
2. Routine labs don't culture toxo.
3. PCR on whole blood or tissue |
|
|
Term
| What is the Rx for toxoplasmosis? |
|
Definition
1. Asymptomatic (IgG +,IgM -), no Rx
2. Lymphadenopathy in normals: no Rx
3. HIV toxo encephalitis:
a. Pyrimethamine plus sulfadiazine
b. Pyrimethamine plus clindamycin. |
|
|
Term
| What are the clinical presentation of P. carinii in immunocompromised (AIDS) patients? |
|
Definition
| Pneumonia: shortness of breath, non-productive cough, fever, decreased oxygen levels, bilateral interstitial infiltrates in x-rays |
|
|
Term
| What is the Rx for P. carinii? |
|
Definition
1. DOC: antibiotic: trimethoprim-sulfamethoxazole (TMP-SMX)
2. Trimethoprim + dapsone or pentamidine alone.
3. Oxygen, ventilator
4. Corticosteriods in moderate cases. |
|
|
Term
| What is the Rx for P. carinii? |
|
Definition
1. DOC: antibiotic: trimethoprim-sulfamethoxazole (TMP-SMX)
2. Trimethoprim + dapsone or pentamidine alone.
3. Oxygen, ventilator
4. Corticosteriods in moderate cases. |
|
|
Term
| What is the Dx for P. carinii? |
|
Definition
1. Deep sputum specimens/bronchoscopy/bronchoaveolar lavage. Use silver stains to find cysts or Giemsa stains for trophs.
2. If that is -, pulmonary consultation, transbronchial biopsy
3. PCR: research tool |
|
|
Term
| What are the clinical presentations of African trypanosomiasis: sleeping sickness? |
|
Definition
Caused by T. brucei with two subspecies:
1. T.b.gambiense: W. African sleeping sickness, incubation 2 wks-yrs.
2.T.b. rhodesiense: E. African sleeping sickness w/ 2 wk incubation.
Fever, lymphadenopathy, headache, lethargy, behavioral change, if not treated, episodic sleep-like stages:coma |
|
|
Term
| What is the life cycle of African sleeping sickness? |
|
Definition
1.Tsetse fly bites human
2. Inoculates parasite in subcut pool of blood +/- erythema and chancre
3. Low grade parasitemia in bloodstream and lymphatics.
4. CNS dissemination (w/in wks for rhodesiense, yrs for gambiense)
5. Sleeping sickness (meningoencephalitis)
5. |
|
|
Term
| What is the Dx for African sleeping sickness? |
|
Definition
| Microscopic exam of chancre fluid, lymph node aspirates, blood/bone marrow, CSF |
|
|
Term
| What is the Rx for African sleeping sickness? |
|
Definition
| Pentamidine IM or suramin. |
|
|
Term
| What impact does African sleeping sickness have on Africa? |
|
Definition
| Outbreaks: lg # deaths, force villages to move. It has restricted land use, not allowing favorable agricultural land to be developed. |
|
|
Term
| How do you prevent African sleeping sickness? |
|
Definition
| Try decreasing tsetse vectors, very difficult. |
|
|
Term
| What are the clinical presentations of American Trypanosomiasis: Chagas Disease? |
|
Definition
Caused by Trypanosoma cruzi
1.Acute phase: fever, local swelling, periorbital edema, myocarditis, adenopathy, may last weeks.
2.Asymptomatic phase/resolution phase: most patients
3. Chronic phase: months-years
a.Cardiomyopathy with CHF, irregular HR
b. Megaesophagous: aspiration
c. Megacolon: constipation |
|
|
Term
| What is the Dx of Chagas Disease? |
|
Definition
1. ID trypanozones in blood for acute disease.
2. Serologic test for antibodies for chronic infection: indirect hemagglutination, EIA, immunofluorescent assays
3. Xenodiagnosis:where uninfected reduviid bugs fed on infected blood, gut checked for parasites 4-6 wks later. |
|
|
Term
| What are the key aspects of Leishmaniasis life-cycle? |
|
Definition
1. Female phlebotomine sandflies bites dogs/humans.
2.Protozoan infect human during blood meal.
3. Parasite is phagocytized by macrophages.
4.Parasite in human in form called amastigotes, multiplies.
5. Infect tissues (skin, organs).
6. The sandflies reinfected if bite infected host. |
|
|
Term
| What are the clinical presentations of Leishmaniasis? |
|
Definition
1. Visceral Leishmaniasis:heptosplenomegaly, fever, wght. loss, death due to secondary bacterial/viral infection, opportunistic infection for the immunosuppressed.
2.Cutaneous Leishmaniasis: chronic skin lesions: ulcerative, single/multi, may have "volcano " phase.
3. Mucosal Leishmaniasis: skin lesions that heal, metastatic mucosal lesions in nose, mouth, upper airways. |
|
|
Term
| What is hte Dx for Leishmaniasis? |
|
Definition
1. Microscopic Giemsa-stained slides of tissue, looking for amastigotes. Skin Bx in cutaneous form, bone marrow aspirate/bx in visceral form
2.Culture aspirate/bx, ELISA, immunofluoresescence antibody + in visceral/mucosal, not cutaneous. |
|
|
Term
| Where is Babesiosis endemic? |
|
Definition
| Tick borne disease in U.S. and Europe. |
|
|
Term
| What are hte clinical presentations of Babesiosis? |
|
Definition
| Malaria-like fever, chills, malaise, nonspecific. subacute onset. Many w/ subclinical infection: 10-20% population in endemic area are +. Some critically ill with hypotension, ARDS |
|
|
Term
| How do you make a Babesiosis Dx? |
|
Definition
1. Microscopic exam of blood smear: Giemsa or Wright stain, thick/thin blood smears. Look for intracellular forms in "Maltese Cross"
2. Antibody: indirect immunofluorescent test
3. PCR on blood |
|
|
Term
| What are the clinical presentation of coccidians? |
|
Definition
1. normal host: diarrhea that spontaneously resolves.
2. immunocompromised host: chronic diarrhea |
|
|
Term
| How do you Dx coccidians? |
|
Definition
1.Micro lab ID oocytes in stool
2.Duodenal aspirate and small bowel bx examined |
|
|
Term
| What is the difference b/w protozoans and helminths? |
|
Definition
Protozoans:Unicellular, small, multi hosts:disease, no eosinophilia, Rx aim: eradicate in human.
Helminths: multicell, complex nervous, excretory, repro systems, can be large, don't multiply w/in host: reinfection increase inoculum, if tissue migrate:increase blood eosinophils, Rx aim to decrease inoculum/load. |
|
|
Term
|
Definition
| The flat body/tail making up a chain of independent segments. Each one has male and female sex organs. Can be pregnant and make eggs. Worm grows by adding proglottids near scolex (head). May appear in stool, good for Dx. Oldest ones at distal end. |
|
|
Term
| What is meant by cysticerus in Taenia spp. infections? |
|
Definition
| It is the larval stage in tapeworms. When the intermediate host is infected these larvae are in the muscle. |
|
|
Term
| What is meant by a cysticerosis in Taenia solium (prok tapeworm) infection? |
|
Definition
| It is an infection w/ eggs leading to dissemination in cyst formation. |
|
|
Term
| What are the benign clinical syptoms of T. saginata (beef tapeworm)? |
|
Definition
1. majority asymptomatic.
2. Sometimes non specific epigastric discomfort.
3. Proglottids are motile, climb thru anus, feel movement, tickling. |
|
|
Term
| What are the serious clinical problems with T. solium cysticerosis? |
|
Definition
| 1. Neurocysticercosis: seizures, paresis, mental deterioration, meningitis. |
|
|
Term
| How do you prevent Taenia spp infections? |
|
Definition
1. Cook beef and pork well, freeze.
2. Good personal hygiene, sanitation.
3. Rx adult worm infections to decrease contamination risk. |
|
|
Term
| How do you diagnose Taenia saginata infections? |
|
Definition
1. Examine stool for: proglotidds (motile), adult worms may be 6+ m!
2. The larger the # proglottids, distinguish between the cow and pig worms. |
|
|
Term
| How do you diagnose Taenia solium infections? |
|
Definition
1. Exam stool for eggs or non-motile proglotidds.
2. MRI to see disseminated cysts.
3. Serology done in cysticercosis. |
|
|
Term
| What are the clinical presentations of D. latum? |
|
Definition
1. Mild abdominal bloating, diarrhea, most pateints asymptomatic.
2. Megaloblastic anemia: vitamin B12 deficiency.
3. Massive infections: intestinal obstruction |
|
|
Term
| What are the infected food sources of D. latum? |
|
Definition
| Crustaceans (small snails), small and large fish. |
|
|
Term
|
Definition
1. Stoll exam for eggs: oval or ellipsoidal w/ operculum at one end.
2. Proglottids |
|
|
Term
|
Definition
1. Praziquantal: one dose.
2. Niclosamide, one dose. |
|
|
Term
| How do you prevent D. latum? |
|
Definition
| Proper disposal of human feces.eat well cook fish |
|
|
Term
| How does one acquire Echinococcus granulosus? |
|
Definition
| Ingesting the eggs in feces from infected dogs. |
|
|
Term
| What organs does E. granulosus infect? |
|
Definition
|
|
Term
| What are the clinical presentation of E. granulosus? |
|
Definition
1. In liver, mass effect, abdominal pain
2. Lungs, no sxs or cough, discomfort, blood
3. If cyst ruptures: fever, allergic reactins to parasite antigens. |
|
|
Term
| How would you Dx someone with possible hydatid cysts? |
|
Definition
1. Echo, CT
2. Serologic tests: Enzyme immunoassay, Indirect fluorescent antibody, careful aspiration of hepatic cysts. |
|
|
Term
| What is the general life cylce of schistosmiasis? |
|
Definition
1. Eggs in feces.
2. Miracidia hatch from eggs in water
3. Larval multiply in snail
4. Cercaria enter unbroken skin of human
5. Worms migrate from liver to mesenteric veins. |
|
|
Term
| What are the Ssx of chronic schistosomiasis? |
|
Definition
1. fatigue, abdominal pain, intermittent diarrhea, hepatomegaly, hematuria, hematemesis
2. chronic inflammation with granuloma formation in liver, intestines, bladder
a) secondary rxn to eggs:fibrosis
b) eggs can get into the liver: fibrosis/cirrhosis, cause portal hypertension. or to colon c, cause polyps, diarrhea
3. S maematobium causes lesions in bladder, ureters (hematuria, cystitis)
4. Eggs lodged in lungs (pulmonary hypertension), Spinal cord (inflammation, transverse myelitis).
5. Cell mediated immunity |
|
|
Term
| How do you Dx schistosomiasis? |
|
Definition
1. look for traveler hx to endemic area and water contact.
2. Examine stoll: S. mansoni ovum have a lateral spine, S. haematobium ovum have a terminal spine
3. urine exam
4. antibody detection
5. eosinophilia
6. Tissue bx (bladder for S. haematobium, rectal bx for other spp.) |
|
|
Term
| What is the DOC for Rx schistosomiasis? |
|
Definition
|
|
Term
| How do you minimize the risk of acquiring schitosomiasis? |
|
Definition
1. Avoid fresh water swimming in endemic areas
2. Decrease snail population
3. better sanitation |
|
|
Term
| What is the life cycle of Clonorchis sinesis (liver fluke). |
|
Definition
1. Infected humans pass eggs in feces, contaminate water supplies, snail infection, cercariae
2. Cercariae infect fresh water fish
3. Infected fish eaten by human
4. Fluke dev/mature in human bile ducts |
|
|
Term
| What are clinical manifestations of liver flukes? |
|
Definition
1. Biliary obstruction: cholangitis, obstructive hepatitis syndrome
2. Increase risk of cholangiocarcinoma |
|
|
Term
| What is the life cycle of Paragonimus westermani (lung flukes)? |
|
Definition
1. Human eats uncooked, pickled crabs, crayfish. Parasite ingested is metacercariae
2. Excysts in duodenum, penetrate intestinal wall, abdominal cavity, migrate thru diaphragm, infect lungs.
2. adult worm in lung parenchyma. eggs can be coughed up or found in feces is sputum swallowed.
3. Human feces with eggs get in ground water, infect snail, infect crabs |
|
|
Term
| How do you Dx pulmonary paragonimiasis? |
|
Definition
1. eggs in sputum, stool
2. eosinophilia: nonspecific
3. Antibody : EIA |
|
|
Term
| What are the general characterisitcs of roundworms? |
|
Definition
1. Elongated, cylindrical, full GI tract
2. Not segmented
3. variable size
4. variable life span
5. variable pathogenicity |
|
|
Term
| What are the major types of round worms? |
|
Definition
1. Intestinal: gut only
Pinworm (Enterobius)
Whipworm (Trichuris)
gut/tissue phase (Ascaris, hookworm)
gut, skin, tissue (strongyloids).
2. Tissue: Trichinellosis, Filariasis
3. Nematodes |
|
|
Term
| What are the clinical presentations of Enterobius vermicularis (pinworm)? |
|
Definition
1. majority w/out ssx
2. Pruritis ani: perianal itching, fingernail contamination, oral spread.
3. rarely vaginitis or up in fallopian tube, inflammation |
|
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Term
| What is the Dx for Enterobius vermicularis (pinworm)? |
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Definition
| Morning "scotch tape" touch prep before pooping and bathing. Look for eggs on tape under microscope |
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Term
| How to you Rx Enterobius vermicularis (pinworm)? |
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Definition
1. DOC: pyrantel pamoate
2. mebendazole or albendazole
3. bath in morning |
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Term
| How do you prevent Enterobius vermicularis (pinworm)? |
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Definition
| 1. better personal hygeine |
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Term
| What does an Ascariasis infection look like? |
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Definition
1. light infections: asymptomatic, may pass a worm!
2. heavy infection: malnutrition, impaired physical, cognitive function
biliary obstruction, lower intestinal obstruction: appendicitis, lg. bowel obstruction, pancreatitis., lung symptoms: cough, hemoptysis, transient lung infiltrates (Loeffler's Syndrome), asthma like ssx, worms can be coughed up! |
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Term
| What does an adult Ascariasis worm look like? |
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Definition
| Tapered ends, 15-35 cm long. |
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Term
| How do you Dx an Ascariasis infection? |
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Definition
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Term
| What is the general life cycle of hookworm? |
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Definition
1. Eggs in stool.
2. Rhabditiform larvae develop in soil into infective 3rd stage filariform larvae
3. filariform larvea penetrate skin or are ingested
4. adult worms live in bowel, cause eosiniphilia, abdomnial pain, anemia
4. migrate via bloodstream to lungs |
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Term
| How do you diagnose hookworm? |
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Definition
1. stool exam, look for eggs
2. hints: anemia, eosinophilia |
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Term
| How does whipworm (Trichuris trichuria) clinically present? |
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Definition
1. most asymptomatic
2. Heavy infection: diarrhea, abdominal pain, rectal prolapse, anemia, growth retardation |
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Term
| How do you Dx whipworm (Trichuris trichuria) ? |
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Definition
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Term
| What is the life cycle for Strongyloides stercalis? |
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Definition
1. Eggs hatch into rhabditiform larvae (non infectious)
2. In soil or Anus (Autoinfection)
3. become filariform larvae (infectious) in skin, pass to blood, to lungs.
4. Adult form in gut |
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Term
| What is the significance of "autoinfection" in Strongyloides stercalis? |
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Definition
In hosts GI tract, non-infectious rhabitiform larvae able to become infectious filariform larvae which may:
1. invade intestinal mucosa, disseminate into human.
2. passed to peri-anal skin area, invade skin to reinfect |
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Term
| Why would a clinician test for "subclinical infection" with Strongyloides stercalis? |
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Definition
| If patient has a hx of living in an endemic area and then needs immunosupression later |
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Term
| Why may Loeffler's syndrome occur in Strongyloides stercalis? |
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Definition
| Because the faliciform larvae may pass into the lungs. |
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Term
| What are the clinical presentations of trichinellosis? |
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Definition
1. Most asymptomatic
2. Diarrhe +/- vomit, fever, muscle aches, periorbital edema
3. eosinophilia
4. high inoculum may cause myocarditis |
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Term
| How do you Dx trichinellosis? |
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Definition
1. clinical suspision: myositis + eosinophilia
2. muscle Bx for larvae
3. serum antibody |
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Term
| What are the two major forms of filariasis? |
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Definition
1. lymphatic form
2. Onchocerciasis form (river blindness) |
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Term
| How does the lymphatic form of filariasis clinically present? |
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Definition
1. majority asympotomatic
2. Acute inflammatory disease: lower extremety lymphadenitis, orchitis, epididymitis
3. Chronic -obstructive phase: lymphatic obstruction: reurrent acute lymphadentitis, elephantitiasis |
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Term
| How does onchoceriasis (river blindness) filariasis clinically present? |
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Definition
1. nontender benign skin nodules
2. dermatitis, lymphadenopathy
3. eye lesions: keratitis, conjunctivitis with scarring: blindness |
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Term
| What is the vector of lymphatic filariasis? |
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Definition
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Term
| How do you Dx lymphatic filariasis? |
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Definition
1. prolong Hx of exposure in endemic areas
2. thickened spermatic cord/ swollen extremity...elephantiasis
3. increase eosinophilia w/ acute episodes
4. blood smears: look for microfilariae |
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Term
| How is onchocerciasis acquired and how can blindness occur? |
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Definition
| Black fly bites. Adult worms (microfilariae migrate thru skin to conjuntiva, cause blindness. |
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Term
| What are the clinical presentations of "guinea worm" (Dracunculiasis)? |
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Definition
| skin ulceration after worm emerges, risk of secondary infection |
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Term
| How do people acquire "guinea worm"? |
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Definition
| Drinking unfiltered water with small crustaceans with the infected larvae |
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