MLT 240 Final Exam Study Guide Flashcards by Alex Olsen

List the asexual and sexual spores of fungi and give an example of an organism which exhibits each type.

know asexual

arthospores, blastospores, chlamydospres

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Thick-walled, broad-based yeast

Blastomyces dermatiditis

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Spherules filled with endospores

Coccidioides imitis

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Thick-wall barrel-shaped arthrospores

Coccidioides imits

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Spiny tuberculate macroconidia

Histoplasma capsulatum

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Brown sclerotic bodies

Chromomycosis dermatiaceous fungi

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Thick-walled, spindle-shaped macroconidia

Microsporum canis

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Colony has a red reverse

Trichtophyton rubrum

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Thin-walled, club-shaped macroconidia in clusters

Epidermophyton

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Produces germ tube

Candida albicans

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Causes epidemic scalp ringworm

Trichtophyton tonsurans

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Broad, non-septate hypae in tissue

Mucor/Rhizopus

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Brown, gritty deposits in sputum

Aspergillis

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Multiple buds in tissue

Paracoccidioides

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Causes Phycomycoses

Mucor/Rhizopus

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List the species of rickettsia, their mode of transmission (vectors), and the diseases they cause

know RMSF
deer tick
R. rickettsi

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How do rickettsia differ from chlamydia

no vectors for Chlamydia

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What diseases are caused by chlamydia and how are they spread

psittacosis

aerosol; birds

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Burkitt’s lymphoma

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Infectious mononucleosis

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Large, red intranuclear inclusions

CMV

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Negri bodies

Rabies

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Shingles

Varicella Zoster

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host in which the adult(sexual stage) of the life cycle occurs

definitive host

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host in which the larval(asexual stage) of the life cycle occurs

intermediate host

animals other than man that harbor human parasites; serve as a source of infection

reservoir host

List the four classes of protozoa and their means of motility

sarcodina - pseudopods ciliata - cilia mastigophora - flagella sporozoa - no means of motility

Sluggish random motility

Entamoeba coli

Fine, even peripheral chromatin

Entamoeba histolytica

Oval cyst has large, blot-like karyosome

Endolimax nana

Large glycogen vacuole stains deeply with iodine

Iodamoeba butschlii

Lacks a cyst form

Dientamoeba fragilis Entamoeba gingivalis Trichomonas vaginalis

Troph is bilaterally symmetrical

Giardia lamblia

Pear-shaped troph with jerky motility is found in urine

Trichomonas vaginalis

Cyst is lemon-shaped with “nipple” on end

Chilomastix mesnili

How are most protozoan diseases transmitted

fecal-oral route | infective cyst stage

What morphological form of the blood and tissue flagellates is intracellular? Which species exist in this form in human cells?

Leischmanial form L-D bodies Leischmania sp and Trypansoma cruzii

West African/Gambian sleeping sickness, tsetse fly

Trypansoma gambiense

Kala-azar, LD bodies, sand fly

Leischmania donovani

espundia, sand fly

Leischmania braziliensis

oriental sore, Baghdad/Delhi boil, sand fly

Leischmani tropica

Chaga's disease, kissing bug

Tyrpansoma cruzii

East african/Rhodesian sleeping sickness, tsetse fly

Trypansoma rhodesiense

Phlebotomas

sandflies

Describe the principle and interpretation of the Sabin-Feldman dye test

In a positive test, Toxoplasma gondii will not take up the dye. **In absence of the antibodies it will stain blue**

What is the first intermediate host of all human flukes

snails

Usual parasite of sheep has an extremely large egg

Fasciola hepatica

Largest fluke found in man

Fasciolopsis buski

Ova often confused with Diphyllobothrium latum

Paragonimus westermani

Egg has prominent shoulders and resembles a light bulb

Clonorchis sinensis

“Bladder fluke” associated with bladder cancer

Schistosoma haematobium

Ova can appear in the stool or sputum

Paragonimus wetermani

larval stage of Echinococcus granulosis; tapeworm larvae large bladder filled cyst

hydatid cyst

individual segments of a tapeworm

proglottid

narrowest part of the tapeworm, located just behind the scolex

neck

fleshy extension of scolex

rostellum

head of a tapeworm may have suckers (4), bothria (2) or hooks; organ for attachment

scolex

general term for entire tapeworm

strobila

definitive host: man *intermediate host: freshwater fish diagnostic stage:egg *infective stage: plerocercoid

Diphyllobothrium latum

definitive host: man *intermediate host: cow diagnostic stage: egg *infective stage: cysticercus bovis

Taenia saginata; more branches, no hooks

definitive host: man intermediate host: pig diagnostic stage:egg infective stage: cysticercus cellulosae

Taenia solium; 7-13 branches, hooks(armed)

definitive host: man intermediate host: none diagnostic stage: egg infective stage: fully embryonated egg

Hymenolepsis nana - dwarf tapeworm; polar filaments

definitive host: rat intermediate host: grain beetle, flea diagnostic stage:egg infective stage: cystercoid

Hymenolepsis diminuta

Echinoccus granulosus definitive host: canines intermediate host: sheep diagnostic stage: hydatid cyst which is found in man infective stage: egg

Echinoccus granulosus

How can Taenia saginata and Taenia solium be differentiated?

eggs of each are indistinguishable. Uterus of T. solium has only 7-15 lateral branches. T. saginata has more uterine branches, no hooks on scolex. Man can be infected by T. solium eggs but not by T. saginata eggs

How can Hymeolepis nana and Hymenolepis dimunata be differentiated? Which is the dwarf tapeworm?

H. diminuta eggs are larger and have no polar filaments H. nana

What are spicules?

associated in nematode with ejaculating duct- in males; necessary for reproduction

How does the life cycle of nematodes differ from that of trematodes?

nematodes have a more simple life cycle, 1 host and external environment, *alternate between free living and parasitic* trematodes have at least 1 if not 2 intermediate hosts *parasitic*

definitive host: man intermediate host: none diagnostic stage: egg **infective stage: embryonated egg**

Ascaris lumbricoides -roundworm

definitive host: man intermediate host: none diagnostic stage: egg **infective stage: embryonated egg

Enterobius vermicularis - **pinworm**

definitive host: man intermediate host: none diagnostic stage: egg *infective stage: filariform larvae*

Necator americanus - hookworm

definitive host: man intermediate host: none diagnostic stage: rhadbitiform larvae *infective stage: filariform larvae*

Strongyloides stercoralis - threadworm

definitive host: man *intermediate host: pig* diagnostic stage: encysted larvae *infective stage: encysted larvae in muscle*

Trichinella spiralis - pork tapeworm

``` definitive host: man intermediate host: none diagnostic stage: egg *infective stage: embryonated egg* *polar plugs, barrel shaped* ```

Trichuris trichiuria - whipworm

How can the rhabditiform larvae of hookworm and Strongyloides be differentiated? How are infections due to these organisms usually acquired?

rhabditiform (N. americanus)- long buccal cavity strongyloides-short buccal cavity penetration of skin by filariform larvae

In the life cycle of Strongylodies, what do the terms autoinfection, direct development, and indirect development refer to?

- person infects themselves | - like hookworm rhabditifom directly develops into filariform -rhabditiform develops into a free living adults

What is visceral larval migrans and what is it cause by? | Cutaneous larval migrans (creeping eruptions)?

Toxocara canis **Ancylostoma braziliense**

List several species of protozoa or helminthes which can be diagnosed by observation of a stained blood smear.

plasmodium trypansoma leischmania microfilaria

List several distinctive features of filarial worms.

presence of nuclei (in tail) helps to id some have sheath derived from eggshell have periodicity; female gives birth to live larvae

How do Wuchereria bancrofti and Brugia malaya differ?

both cause elephantiasis and live in lymphatic system. *BRUGIA HAS A MUCH HIGHER NUMBER OF MICROFILARIA IN THE BLOODSTREAM* bancrofti is sheathed and Malaya is not

intermediate host: mosquito specimen needed for diagnosis: blood disease caused: elephantiasis diagnostic stage: microfilaria

Brugia malaya

intermediate host: Cyclops/copepod specimen needed for diagnosis: skin disease caused: dracunculosis diagnostic stage: rhabditiform larvae

**Dracunculus medinnesis-guniea worm**

intermediate host: chrysops fly (deer fly) specimen needed for diagnosis: blood *disease caused: loiasis (severe eye disease)** diagnostic stage: microfilaria

Loa Loa

**intermediate host: simulium fly (black fly) specimen needed for diagnosis: skin*** disease caused: river blindness diagnostic stage:microfilaria

Onchocerca volvulus

intermediate host: mosquito specimen needed for diagnosis: blood disease caused: elephantiasis diagnostic stage:microfilaria

Wuchereria bancrofti

If an ova and parasite exam can not be performed right away, what procedure should be followed?

perform quick macro and micro exam, add preservative and refrigerate within 30 min

What preservative is usually used for the trichrome stain?

PVA

What is the main use of a permanent stained smear?

to see protozoan cyst and trophs

List the two major concentration procedures and the principle of each. What is the specific gravity of the solution employed in the flotation method?

formalin ether- sedimentation zinc sulfate-flotation 1.18

If negative results were obtained using the zinc sulfate method, what would be the best course to follow if the doctor still felt the patient had a parasitic disease?

Repeat using formalin ether

What parasite often causes pneumonitis in children?

Ascaris

In which two parasitic infections is autoinfection most common?

pinworm | strongyloides

List several species of parasites which can be transmitted by contaminated drinking water

E. histolytica, all schistosomes (not HOOKWORMS)

List several environmental or climatic factors which are important in the spread and/or prevention of parasitic infections

temp, sand, soil, controlling insect population, water filtration

*bilhariasis

*Schistosoma sp.

blackwater fever

Plasmodium falciparum

guinea worm

Dracunculus medinensis

thread worm

Strongyloides stercoralis

eye worm

Loa Loa

whip worm

Trichuris trichiura

split ring forms

P. falciparum

oval, irregular cytoplasm (fimbriated)

P. ovale

9 merozoites

P. malariae

rbc's enlarged ,infects retics, Schufners granules

P. vivax

intermediate host: common name: blood fluke infective stage: penetration of hosts skin by circaria

Schistosma sp.

common name: Chinese liver fluke intermediate host: fish infective stage: eating infected fish

Clonorchis sinensis

common name: intestinal fluke intermediate host: water plants infective stage: eating infected water plants (watercress)

Fasciolopsis buski

common name: lung fluke intermediate host: snails infective stage: eating infected freshwater crustaceans

Paragonimus westermani

MLT 240 Final Exam Study Guide Flashcards

(108 cards)